add Eigen as a dependency

This commit is contained in:
Sven Czarnian
2021-12-16 15:59:56 +01:00
parent a08ac9b244
commit 27b422d806
479 changed files with 167893 additions and 0 deletions

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Claire Maurice
// Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010,2012 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_COMPLEX_EIGEN_SOLVER_H
#define EIGEN_COMPLEX_EIGEN_SOLVER_H
#include "./ComplexSchur.h"
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class ComplexEigenSolver
*
* \brief Computes eigenvalues and eigenvectors of general complex matrices
*
* \tparam _MatrixType the type of the matrix of which we are
* computing the eigendecomposition; this is expected to be an
* instantiation of the Matrix class template.
*
* The eigenvalues and eigenvectors of a matrix \f$ A \f$ are scalars
* \f$ \lambda \f$ and vectors \f$ v \f$ such that \f$ Av = \lambda v
* \f$. If \f$ D \f$ is a diagonal matrix with the eigenvalues on
* the diagonal, and \f$ V \f$ is a matrix with the eigenvectors as
* its columns, then \f$ A V = V D \f$. The matrix \f$ V \f$ is
* almost always invertible, in which case we have \f$ A = V D V^{-1}
* \f$. This is called the eigendecomposition.
*
* The main function in this class is compute(), which computes the
* eigenvalues and eigenvectors of a given function. The
* documentation for that function contains an example showing the
* main features of the class.
*
* \sa class EigenSolver, class SelfAdjointEigenSolver
*/
template<typename _MatrixType> class ComplexEigenSolver
{
public:
/** \brief Synonym for the template parameter \p _MatrixType. */
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
/** \brief Scalar type for matrices of type #MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
/** \brief Complex scalar type for #MatrixType.
*
* This is \c std::complex<Scalar> if #Scalar is real (e.g.,
* \c float or \c double) and just \c Scalar if #Scalar is
* complex.
*/
typedef std::complex<RealScalar> ComplexScalar;
/** \brief Type for vector of eigenvalues as returned by eigenvalues().
*
* This is a column vector with entries of type #ComplexScalar.
* The length of the vector is the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, ColsAtCompileTime, 1, Options&(~RowMajor), MaxColsAtCompileTime, 1> EigenvalueType;
/** \brief Type for matrix of eigenvectors as returned by eigenvectors().
*
* This is a square matrix with entries of type #ComplexScalar.
* The size is the same as the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, RowsAtCompileTime, ColsAtCompileTime, Options, MaxRowsAtCompileTime, MaxColsAtCompileTime> EigenvectorType;
/** \brief Default constructor.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute().
*/
ComplexEigenSolver()
: m_eivec(),
m_eivalues(),
m_schur(),
m_isInitialized(false),
m_eigenvectorsOk(false),
m_matX()
{}
/** \brief Default Constructor with memory preallocation
*
* Like the default constructor but with preallocation of the internal data
* according to the specified problem \a size.
* \sa ComplexEigenSolver()
*/
explicit ComplexEigenSolver(Index size)
: m_eivec(size, size),
m_eivalues(size),
m_schur(size),
m_isInitialized(false),
m_eigenvectorsOk(false),
m_matX(size, size)
{}
/** \brief Constructor; computes eigendecomposition of given matrix.
*
* \param[in] matrix Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are
* computed.
*
* This constructor calls compute() to compute the eigendecomposition.
*/
template<typename InputType>
explicit ComplexEigenSolver(const EigenBase<InputType>& matrix, bool computeEigenvectors = true)
: m_eivec(matrix.rows(),matrix.cols()),
m_eivalues(matrix.cols()),
m_schur(matrix.rows()),
m_isInitialized(false),
m_eigenvectorsOk(false),
m_matX(matrix.rows(),matrix.cols())
{
compute(matrix.derived(), computeEigenvectors);
}
/** \brief Returns the eigenvectors of given matrix.
*
* \returns A const reference to the matrix whose columns are the eigenvectors.
*
* \pre Either the constructor
* ComplexEigenSolver(const MatrixType& matrix, bool) or the member
* function compute(const MatrixType& matrix, bool) has been called before
* to compute the eigendecomposition of a matrix, and
* \p computeEigenvectors was set to true (the default).
*
* This function returns a matrix whose columns are the eigenvectors. Column
* \f$ k \f$ is an eigenvector corresponding to eigenvalue number \f$ k
* \f$ as returned by eigenvalues(). The eigenvectors are normalized to
* have (Euclidean) norm equal to one. The matrix returned by this
* function is the matrix \f$ V \f$ in the eigendecomposition \f$ A = V D
* V^{-1} \f$, if it exists.
*
* Example: \include ComplexEigenSolver_eigenvectors.cpp
* Output: \verbinclude ComplexEigenSolver_eigenvectors.out
*/
const EigenvectorType& eigenvectors() const
{
eigen_assert(m_isInitialized && "ComplexEigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
return m_eivec;
}
/** \brief Returns the eigenvalues of given matrix.
*
* \returns A const reference to the column vector containing the eigenvalues.
*
* \pre Either the constructor
* ComplexEigenSolver(const MatrixType& matrix, bool) or the member
* function compute(const MatrixType& matrix, bool) has been called before
* to compute the eigendecomposition of a matrix.
*
* This function returns a column vector containing the
* eigenvalues. Eigenvalues are repeated according to their
* algebraic multiplicity, so there are as many eigenvalues as
* rows in the matrix. The eigenvalues are not sorted in any particular
* order.
*
* Example: \include ComplexEigenSolver_eigenvalues.cpp
* Output: \verbinclude ComplexEigenSolver_eigenvalues.out
*/
const EigenvalueType& eigenvalues() const
{
eigen_assert(m_isInitialized && "ComplexEigenSolver is not initialized.");
return m_eivalues;
}
/** \brief Computes eigendecomposition of given matrix.
*
* \param[in] matrix Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are
* computed.
* \returns Reference to \c *this
*
* This function computes the eigenvalues of the complex matrix \p matrix.
* The eigenvalues() function can be used to retrieve them. If
* \p computeEigenvectors is true, then the eigenvectors are also computed
* and can be retrieved by calling eigenvectors().
*
* The matrix is first reduced to Schur form using the
* ComplexSchur class. The Schur decomposition is then used to
* compute the eigenvalues and eigenvectors.
*
* The cost of the computation is dominated by the cost of the
* Schur decomposition, which is \f$ O(n^3) \f$ where \f$ n \f$
* is the size of the matrix.
*
* Example: \include ComplexEigenSolver_compute.cpp
* Output: \verbinclude ComplexEigenSolver_compute.out
*/
template<typename InputType>
ComplexEigenSolver& compute(const EigenBase<InputType>& matrix, bool computeEigenvectors = true);
/** \brief Reports whether previous computation was successful.
*
* \returns \c Success if computation was succesful, \c NoConvergence otherwise.
*/
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "ComplexEigenSolver is not initialized.");
return m_schur.info();
}
/** \brief Sets the maximum number of iterations allowed. */
ComplexEigenSolver& setMaxIterations(Index maxIters)
{
m_schur.setMaxIterations(maxIters);
return *this;
}
/** \brief Returns the maximum number of iterations. */
Index getMaxIterations()
{
return m_schur.getMaxIterations();
}
protected:
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
}
EigenvectorType m_eivec;
EigenvalueType m_eivalues;
ComplexSchur<MatrixType> m_schur;
bool m_isInitialized;
bool m_eigenvectorsOk;
EigenvectorType m_matX;
private:
void doComputeEigenvectors(RealScalar matrixnorm);
void sortEigenvalues(bool computeEigenvectors);
};
template<typename MatrixType>
template<typename InputType>
ComplexEigenSolver<MatrixType>&
ComplexEigenSolver<MatrixType>::compute(const EigenBase<InputType>& matrix, bool computeEigenvectors)
{
check_template_parameters();
// this code is inspired from Jampack
eigen_assert(matrix.cols() == matrix.rows());
// Do a complex Schur decomposition, A = U T U^*
// The eigenvalues are on the diagonal of T.
m_schur.compute(matrix.derived(), computeEigenvectors);
if(m_schur.info() == Success)
{
m_eivalues = m_schur.matrixT().diagonal();
if(computeEigenvectors)
doComputeEigenvectors(m_schur.matrixT().norm());
sortEigenvalues(computeEigenvectors);
}
m_isInitialized = true;
m_eigenvectorsOk = computeEigenvectors;
return *this;
}
template<typename MatrixType>
void ComplexEigenSolver<MatrixType>::doComputeEigenvectors(RealScalar matrixnorm)
{
const Index n = m_eivalues.size();
matrixnorm = numext::maxi(matrixnorm,(std::numeric_limits<RealScalar>::min)());
// Compute X such that T = X D X^(-1), where D is the diagonal of T.
// The matrix X is unit triangular.
m_matX = EigenvectorType::Zero(n, n);
for(Index k=n-1 ; k>=0 ; k--)
{
m_matX.coeffRef(k,k) = ComplexScalar(1.0,0.0);
// Compute X(i,k) using the (i,k) entry of the equation X T = D X
for(Index i=k-1 ; i>=0 ; i--)
{
m_matX.coeffRef(i,k) = -m_schur.matrixT().coeff(i,k);
if(k-i-1>0)
m_matX.coeffRef(i,k) -= (m_schur.matrixT().row(i).segment(i+1,k-i-1) * m_matX.col(k).segment(i+1,k-i-1)).value();
ComplexScalar z = m_schur.matrixT().coeff(i,i) - m_schur.matrixT().coeff(k,k);
if(z==ComplexScalar(0))
{
// If the i-th and k-th eigenvalue are equal, then z equals 0.
// Use a small value instead, to prevent division by zero.
numext::real_ref(z) = NumTraits<RealScalar>::epsilon() * matrixnorm;
}
m_matX.coeffRef(i,k) = m_matX.coeff(i,k) / z;
}
}
// Compute V as V = U X; now A = U T U^* = U X D X^(-1) U^* = V D V^(-1)
m_eivec.noalias() = m_schur.matrixU() * m_matX;
// .. and normalize the eigenvectors
for(Index k=0 ; k<n ; k++)
{
m_eivec.col(k).normalize();
}
}
template<typename MatrixType>
void ComplexEigenSolver<MatrixType>::sortEigenvalues(bool computeEigenvectors)
{
const Index n = m_eivalues.size();
for (Index i=0; i<n; i++)
{
Index k;
m_eivalues.cwiseAbs().tail(n-i).minCoeff(&k);
if (k != 0)
{
k += i;
std::swap(m_eivalues[k],m_eivalues[i]);
if(computeEigenvectors)
m_eivec.col(i).swap(m_eivec.col(k));
}
}
}
} // end namespace Eigen
#endif // EIGEN_COMPLEX_EIGEN_SOLVER_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Claire Maurice
// Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010,2012 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_COMPLEX_SCHUR_H
#define EIGEN_COMPLEX_SCHUR_H
#include "./HessenbergDecomposition.h"
namespace Eigen {
namespace internal {
template<typename MatrixType, bool IsComplex> struct complex_schur_reduce_to_hessenberg;
}
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class ComplexSchur
*
* \brief Performs a complex Schur decomposition of a real or complex square matrix
*
* \tparam _MatrixType the type of the matrix of which we are
* computing the Schur decomposition; this is expected to be an
* instantiation of the Matrix class template.
*
* Given a real or complex square matrix A, this class computes the
* Schur decomposition: \f$ A = U T U^*\f$ where U is a unitary
* complex matrix, and T is a complex upper triangular matrix. The
* diagonal of the matrix T corresponds to the eigenvalues of the
* matrix A.
*
* Call the function compute() to compute the Schur decomposition of
* a given matrix. Alternatively, you can use the
* ComplexSchur(const MatrixType&, bool) constructor which computes
* the Schur decomposition at construction time. Once the
* decomposition is computed, you can use the matrixU() and matrixT()
* functions to retrieve the matrices U and V in the decomposition.
*
* \note This code is inspired from Jampack
*
* \sa class RealSchur, class EigenSolver, class ComplexEigenSolver
*/
template<typename _MatrixType> class ComplexSchur
{
public:
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
/** \brief Scalar type for matrices of type \p _MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
/** \brief Complex scalar type for \p _MatrixType.
*
* This is \c std::complex<Scalar> if #Scalar is real (e.g.,
* \c float or \c double) and just \c Scalar if #Scalar is
* complex.
*/
typedef std::complex<RealScalar> ComplexScalar;
/** \brief Type for the matrices in the Schur decomposition.
*
* This is a square matrix with entries of type #ComplexScalar.
* The size is the same as the size of \p _MatrixType.
*/
typedef Matrix<ComplexScalar, RowsAtCompileTime, ColsAtCompileTime, Options, MaxRowsAtCompileTime, MaxColsAtCompileTime> ComplexMatrixType;
/** \brief Default constructor.
*
* \param [in] size Positive integer, size of the matrix whose Schur decomposition will be computed.
*
* The default constructor is useful in cases in which the user
* intends to perform decompositions via compute(). The \p size
* parameter is only used as a hint. It is not an error to give a
* wrong \p size, but it may impair performance.
*
* \sa compute() for an example.
*/
explicit ComplexSchur(Index size = RowsAtCompileTime==Dynamic ? 1 : RowsAtCompileTime)
: m_matT(size,size),
m_matU(size,size),
m_hess(size),
m_isInitialized(false),
m_matUisUptodate(false),
m_maxIters(-1)
{}
/** \brief Constructor; computes Schur decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Schur decomposition is to be computed.
* \param[in] computeU If true, both T and U are computed; if false, only T is computed.
*
* This constructor calls compute() to compute the Schur decomposition.
*
* \sa matrixT() and matrixU() for examples.
*/
template<typename InputType>
explicit ComplexSchur(const EigenBase<InputType>& matrix, bool computeU = true)
: m_matT(matrix.rows(),matrix.cols()),
m_matU(matrix.rows(),matrix.cols()),
m_hess(matrix.rows()),
m_isInitialized(false),
m_matUisUptodate(false),
m_maxIters(-1)
{
compute(matrix.derived(), computeU);
}
/** \brief Returns the unitary matrix in the Schur decomposition.
*
* \returns A const reference to the matrix U.
*
* It is assumed that either the constructor
* ComplexSchur(const MatrixType& matrix, bool computeU) or the
* member function compute(const MatrixType& matrix, bool computeU)
* has been called before to compute the Schur decomposition of a
* matrix, and that \p computeU was set to true (the default
* value).
*
* Example: \include ComplexSchur_matrixU.cpp
* Output: \verbinclude ComplexSchur_matrixU.out
*/
const ComplexMatrixType& matrixU() const
{
eigen_assert(m_isInitialized && "ComplexSchur is not initialized.");
eigen_assert(m_matUisUptodate && "The matrix U has not been computed during the ComplexSchur decomposition.");
return m_matU;
}
/** \brief Returns the triangular matrix in the Schur decomposition.
*
* \returns A const reference to the matrix T.
*
* It is assumed that either the constructor
* ComplexSchur(const MatrixType& matrix, bool computeU) or the
* member function compute(const MatrixType& matrix, bool computeU)
* has been called before to compute the Schur decomposition of a
* matrix.
*
* Note that this function returns a plain square matrix. If you want to reference
* only the upper triangular part, use:
* \code schur.matrixT().triangularView<Upper>() \endcode
*
* Example: \include ComplexSchur_matrixT.cpp
* Output: \verbinclude ComplexSchur_matrixT.out
*/
const ComplexMatrixType& matrixT() const
{
eigen_assert(m_isInitialized && "ComplexSchur is not initialized.");
return m_matT;
}
/** \brief Computes Schur decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Schur decomposition is to be computed.
* \param[in] computeU If true, both T and U are computed; if false, only T is computed.
* \returns Reference to \c *this
*
* The Schur decomposition is computed by first reducing the
* matrix to Hessenberg form using the class
* HessenbergDecomposition. The Hessenberg matrix is then reduced
* to triangular form by performing QR iterations with a single
* shift. The cost of computing the Schur decomposition depends
* on the number of iterations; as a rough guide, it may be taken
* on the number of iterations; as a rough guide, it may be taken
* to be \f$25n^3\f$ complex flops, or \f$10n^3\f$ complex flops
* if \a computeU is false.
*
* Example: \include ComplexSchur_compute.cpp
* Output: \verbinclude ComplexSchur_compute.out
*
* \sa compute(const MatrixType&, bool, Index)
*/
template<typename InputType>
ComplexSchur& compute(const EigenBase<InputType>& matrix, bool computeU = true);
/** \brief Compute Schur decomposition from a given Hessenberg matrix
* \param[in] matrixH Matrix in Hessenberg form H
* \param[in] matrixQ orthogonal matrix Q that transform a matrix A to H : A = Q H Q^T
* \param computeU Computes the matriX U of the Schur vectors
* \return Reference to \c *this
*
* This routine assumes that the matrix is already reduced in Hessenberg form matrixH
* using either the class HessenbergDecomposition or another mean.
* It computes the upper quasi-triangular matrix T of the Schur decomposition of H
* When computeU is true, this routine computes the matrix U such that
* A = U T U^T = (QZ) T (QZ)^T = Q H Q^T where A is the initial matrix
*
* NOTE Q is referenced if computeU is true; so, if the initial orthogonal matrix
* is not available, the user should give an identity matrix (Q.setIdentity())
*
* \sa compute(const MatrixType&, bool)
*/
template<typename HessMatrixType, typename OrthMatrixType>
ComplexSchur& computeFromHessenberg(const HessMatrixType& matrixH, const OrthMatrixType& matrixQ, bool computeU=true);
/** \brief Reports whether previous computation was successful.
*
* \returns \c Success if computation was succesful, \c NoConvergence otherwise.
*/
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "ComplexSchur is not initialized.");
return m_info;
}
/** \brief Sets the maximum number of iterations allowed.
*
* If not specified by the user, the maximum number of iterations is m_maxIterationsPerRow times the size
* of the matrix.
*/
ComplexSchur& setMaxIterations(Index maxIters)
{
m_maxIters = maxIters;
return *this;
}
/** \brief Returns the maximum number of iterations. */
Index getMaxIterations()
{
return m_maxIters;
}
/** \brief Maximum number of iterations per row.
*
* If not otherwise specified, the maximum number of iterations is this number times the size of the
* matrix. It is currently set to 30.
*/
static const int m_maxIterationsPerRow = 30;
protected:
ComplexMatrixType m_matT, m_matU;
HessenbergDecomposition<MatrixType> m_hess;
ComputationInfo m_info;
bool m_isInitialized;
bool m_matUisUptodate;
Index m_maxIters;
private:
bool subdiagonalEntryIsNeglegible(Index i);
ComplexScalar computeShift(Index iu, Index iter);
void reduceToTriangularForm(bool computeU);
friend struct internal::complex_schur_reduce_to_hessenberg<MatrixType, NumTraits<Scalar>::IsComplex>;
};
/** If m_matT(i+1,i) is neglegible in floating point arithmetic
* compared to m_matT(i,i) and m_matT(j,j), then set it to zero and
* return true, else return false. */
template<typename MatrixType>
inline bool ComplexSchur<MatrixType>::subdiagonalEntryIsNeglegible(Index i)
{
RealScalar d = numext::norm1(m_matT.coeff(i,i)) + numext::norm1(m_matT.coeff(i+1,i+1));
RealScalar sd = numext::norm1(m_matT.coeff(i+1,i));
if (internal::isMuchSmallerThan(sd, d, NumTraits<RealScalar>::epsilon()))
{
m_matT.coeffRef(i+1,i) = ComplexScalar(0);
return true;
}
return false;
}
/** Compute the shift in the current QR iteration. */
template<typename MatrixType>
typename ComplexSchur<MatrixType>::ComplexScalar ComplexSchur<MatrixType>::computeShift(Index iu, Index iter)
{
using std::abs;
if (iter == 10 || iter == 20)
{
// exceptional shift, taken from http://www.netlib.org/eispack/comqr.f
return abs(numext::real(m_matT.coeff(iu,iu-1))) + abs(numext::real(m_matT.coeff(iu-1,iu-2)));
}
// compute the shift as one of the eigenvalues of t, the 2x2
// diagonal block on the bottom of the active submatrix
Matrix<ComplexScalar,2,2> t = m_matT.template block<2,2>(iu-1,iu-1);
RealScalar normt = t.cwiseAbs().sum();
t /= normt; // the normalization by sf is to avoid under/overflow
ComplexScalar b = t.coeff(0,1) * t.coeff(1,0);
ComplexScalar c = t.coeff(0,0) - t.coeff(1,1);
ComplexScalar disc = sqrt(c*c + RealScalar(4)*b);
ComplexScalar det = t.coeff(0,0) * t.coeff(1,1) - b;
ComplexScalar trace = t.coeff(0,0) + t.coeff(1,1);
ComplexScalar eival1 = (trace + disc) / RealScalar(2);
ComplexScalar eival2 = (trace - disc) / RealScalar(2);
if(numext::norm1(eival1) > numext::norm1(eival2))
eival2 = det / eival1;
else
eival1 = det / eival2;
// choose the eigenvalue closest to the bottom entry of the diagonal
if(numext::norm1(eival1-t.coeff(1,1)) < numext::norm1(eival2-t.coeff(1,1)))
return normt * eival1;
else
return normt * eival2;
}
template<typename MatrixType>
template<typename InputType>
ComplexSchur<MatrixType>& ComplexSchur<MatrixType>::compute(const EigenBase<InputType>& matrix, bool computeU)
{
m_matUisUptodate = false;
eigen_assert(matrix.cols() == matrix.rows());
if(matrix.cols() == 1)
{
m_matT = matrix.derived().template cast<ComplexScalar>();
if(computeU) m_matU = ComplexMatrixType::Identity(1,1);
m_info = Success;
m_isInitialized = true;
m_matUisUptodate = computeU;
return *this;
}
internal::complex_schur_reduce_to_hessenberg<MatrixType, NumTraits<Scalar>::IsComplex>::run(*this, matrix.derived(), computeU);
computeFromHessenberg(m_matT, m_matU, computeU);
return *this;
}
template<typename MatrixType>
template<typename HessMatrixType, typename OrthMatrixType>
ComplexSchur<MatrixType>& ComplexSchur<MatrixType>::computeFromHessenberg(const HessMatrixType& matrixH, const OrthMatrixType& matrixQ, bool computeU)
{
m_matT = matrixH;
if(computeU)
m_matU = matrixQ;
reduceToTriangularForm(computeU);
return *this;
}
namespace internal {
/* Reduce given matrix to Hessenberg form */
template<typename MatrixType, bool IsComplex>
struct complex_schur_reduce_to_hessenberg
{
// this is the implementation for the case IsComplex = true
static void run(ComplexSchur<MatrixType>& _this, const MatrixType& matrix, bool computeU)
{
_this.m_hess.compute(matrix);
_this.m_matT = _this.m_hess.matrixH();
if(computeU) _this.m_matU = _this.m_hess.matrixQ();
}
};
template<typename MatrixType>
struct complex_schur_reduce_to_hessenberg<MatrixType, false>
{
static void run(ComplexSchur<MatrixType>& _this, const MatrixType& matrix, bool computeU)
{
typedef typename ComplexSchur<MatrixType>::ComplexScalar ComplexScalar;
// Note: m_hess is over RealScalar; m_matT and m_matU is over ComplexScalar
_this.m_hess.compute(matrix);
_this.m_matT = _this.m_hess.matrixH().template cast<ComplexScalar>();
if(computeU)
{
// This may cause an allocation which seems to be avoidable
MatrixType Q = _this.m_hess.matrixQ();
_this.m_matU = Q.template cast<ComplexScalar>();
}
}
};
} // end namespace internal
// Reduce the Hessenberg matrix m_matT to triangular form by QR iteration.
template<typename MatrixType>
void ComplexSchur<MatrixType>::reduceToTriangularForm(bool computeU)
{
Index maxIters = m_maxIters;
if (maxIters == -1)
maxIters = m_maxIterationsPerRow * m_matT.rows();
// The matrix m_matT is divided in three parts.
// Rows 0,...,il-1 are decoupled from the rest because m_matT(il,il-1) is zero.
// Rows il,...,iu is the part we are working on (the active submatrix).
// Rows iu+1,...,end are already brought in triangular form.
Index iu = m_matT.cols() - 1;
Index il;
Index iter = 0; // number of iterations we are working on the (iu,iu) element
Index totalIter = 0; // number of iterations for whole matrix
while(true)
{
// find iu, the bottom row of the active submatrix
while(iu > 0)
{
if(!subdiagonalEntryIsNeglegible(iu-1)) break;
iter = 0;
--iu;
}
// if iu is zero then we are done; the whole matrix is triangularized
if(iu==0) break;
// if we spent too many iterations, we give up
iter++;
totalIter++;
if(totalIter > maxIters) break;
// find il, the top row of the active submatrix
il = iu-1;
while(il > 0 && !subdiagonalEntryIsNeglegible(il-1))
{
--il;
}
/* perform the QR step using Givens rotations. The first rotation
creates a bulge; the (il+2,il) element becomes nonzero. This
bulge is chased down to the bottom of the active submatrix. */
ComplexScalar shift = computeShift(iu, iter);
JacobiRotation<ComplexScalar> rot;
rot.makeGivens(m_matT.coeff(il,il) - shift, m_matT.coeff(il+1,il));
m_matT.rightCols(m_matT.cols()-il).applyOnTheLeft(il, il+1, rot.adjoint());
m_matT.topRows((std::min)(il+2,iu)+1).applyOnTheRight(il, il+1, rot);
if(computeU) m_matU.applyOnTheRight(il, il+1, rot);
for(Index i=il+1 ; i<iu ; i++)
{
rot.makeGivens(m_matT.coeffRef(i,i-1), m_matT.coeffRef(i+1,i-1), &m_matT.coeffRef(i,i-1));
m_matT.coeffRef(i+1,i-1) = ComplexScalar(0);
m_matT.rightCols(m_matT.cols()-i).applyOnTheLeft(i, i+1, rot.adjoint());
m_matT.topRows((std::min)(i+2,iu)+1).applyOnTheRight(i, i+1, rot);
if(computeU) m_matU.applyOnTheRight(i, i+1, rot);
}
}
if(totalIter <= maxIters)
m_info = Success;
else
m_info = NoConvergence;
m_isInitialized = true;
m_matUisUptodate = computeU;
}
} // end namespace Eigen
#endif // EIGEN_COMPLEX_SCHUR_H

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/*
Copyright (c) 2011, Intel Corporation. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its contributors may
be used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
********************************************************************************
* Content : Eigen bindings to LAPACKe
* Complex Schur needed to complex unsymmetrical eigenvalues/eigenvectors.
********************************************************************************
*/
#ifndef EIGEN_COMPLEX_SCHUR_LAPACKE_H
#define EIGEN_COMPLEX_SCHUR_LAPACKE_H
namespace Eigen {
/** \internal Specialization for the data types supported by LAPACKe */
#define EIGEN_LAPACKE_SCHUR_COMPLEX(EIGTYPE, LAPACKE_TYPE, LAPACKE_PREFIX, LAPACKE_PREFIX_U, EIGCOLROW, LAPACKE_COLROW) \
template<> template<typename InputType> inline \
ComplexSchur<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >& \
ComplexSchur<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >::compute(const EigenBase<InputType>& matrix, bool computeU) \
{ \
typedef Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> MatrixType; \
typedef MatrixType::RealScalar RealScalar; \
typedef std::complex<RealScalar> ComplexScalar; \
\
eigen_assert(matrix.cols() == matrix.rows()); \
\
m_matUisUptodate = false; \
if(matrix.cols() == 1) \
{ \
m_matT = matrix.derived().template cast<ComplexScalar>(); \
if(computeU) m_matU = ComplexMatrixType::Identity(1,1); \
m_info = Success; \
m_isInitialized = true; \
m_matUisUptodate = computeU; \
return *this; \
} \
lapack_int n = internal::convert_index<lapack_int>(matrix.cols()), sdim, info; \
lapack_int matrix_order = LAPACKE_COLROW; \
char jobvs, sort='N'; \
LAPACK_##LAPACKE_PREFIX_U##_SELECT1 select = 0; \
jobvs = (computeU) ? 'V' : 'N'; \
m_matU.resize(n, n); \
lapack_int ldvs = internal::convert_index<lapack_int>(m_matU.outerStride()); \
m_matT = matrix; \
lapack_int lda = internal::convert_index<lapack_int>(m_matT.outerStride()); \
Matrix<EIGTYPE, Dynamic, Dynamic> w; \
w.resize(n, 1);\
info = LAPACKE_##LAPACKE_PREFIX##gees( matrix_order, jobvs, sort, select, n, (LAPACKE_TYPE*)m_matT.data(), lda, &sdim, (LAPACKE_TYPE*)w.data(), (LAPACKE_TYPE*)m_matU.data(), ldvs ); \
if(info == 0) \
m_info = Success; \
else \
m_info = NoConvergence; \
\
m_isInitialized = true; \
m_matUisUptodate = computeU; \
return *this; \
\
}
EIGEN_LAPACKE_SCHUR_COMPLEX(dcomplex, lapack_complex_double, z, Z, ColMajor, LAPACK_COL_MAJOR)
EIGEN_LAPACKE_SCHUR_COMPLEX(scomplex, lapack_complex_float, c, C, ColMajor, LAPACK_COL_MAJOR)
EIGEN_LAPACKE_SCHUR_COMPLEX(dcomplex, lapack_complex_double, z, Z, RowMajor, LAPACK_ROW_MAJOR)
EIGEN_LAPACKE_SCHUR_COMPLEX(scomplex, lapack_complex_float, c, C, RowMajor, LAPACK_ROW_MAJOR)
} // end namespace Eigen
#endif // EIGEN_COMPLEX_SCHUR_LAPACKE_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010,2012 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_EIGENSOLVER_H
#define EIGEN_EIGENSOLVER_H
#include "./RealSchur.h"
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class EigenSolver
*
* \brief Computes eigenvalues and eigenvectors of general matrices
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* eigendecomposition; this is expected to be an instantiation of the Matrix
* class template. Currently, only real matrices are supported.
*
* The eigenvalues and eigenvectors of a matrix \f$ A \f$ are scalars
* \f$ \lambda \f$ and vectors \f$ v \f$ such that \f$ Av = \lambda v \f$. If
* \f$ D \f$ is a diagonal matrix with the eigenvalues on the diagonal, and
* \f$ V \f$ is a matrix with the eigenvectors as its columns, then \f$ A V =
* V D \f$. The matrix \f$ V \f$ is almost always invertible, in which case we
* have \f$ A = V D V^{-1} \f$. This is called the eigendecomposition.
*
* The eigenvalues and eigenvectors of a matrix may be complex, even when the
* matrix is real. However, we can choose real matrices \f$ V \f$ and \f$ D
* \f$ satisfying \f$ A V = V D \f$, just like the eigendecomposition, if the
* matrix \f$ D \f$ is not required to be diagonal, but if it is allowed to
* have blocks of the form
* \f[ \begin{bmatrix} u & v \\ -v & u \end{bmatrix} \f]
* (where \f$ u \f$ and \f$ v \f$ are real numbers) on the diagonal. These
* blocks correspond to complex eigenvalue pairs \f$ u \pm iv \f$. We call
* this variant of the eigendecomposition the pseudo-eigendecomposition.
*
* Call the function compute() to compute the eigenvalues and eigenvectors of
* a given matrix. Alternatively, you can use the
* EigenSolver(const MatrixType&, bool) constructor which computes the
* eigenvalues and eigenvectors at construction time. Once the eigenvalue and
* eigenvectors are computed, they can be retrieved with the eigenvalues() and
* eigenvectors() functions. The pseudoEigenvalueMatrix() and
* pseudoEigenvectors() methods allow the construction of the
* pseudo-eigendecomposition.
*
* The documentation for EigenSolver(const MatrixType&, bool) contains an
* example of the typical use of this class.
*
* \note The implementation is adapted from
* <a href="http://math.nist.gov/javanumerics/jama/">JAMA</a> (public domain).
* Their code is based on EISPACK.
*
* \sa MatrixBase::eigenvalues(), class ComplexEigenSolver, class SelfAdjointEigenSolver
*/
template<typename _MatrixType> class EigenSolver
{
public:
/** \brief Synonym for the template parameter \p _MatrixType. */
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
/** \brief Scalar type for matrices of type #MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
/** \brief Complex scalar type for #MatrixType.
*
* This is \c std::complex<Scalar> if #Scalar is real (e.g.,
* \c float or \c double) and just \c Scalar if #Scalar is
* complex.
*/
typedef std::complex<RealScalar> ComplexScalar;
/** \brief Type for vector of eigenvalues as returned by eigenvalues().
*
* This is a column vector with entries of type #ComplexScalar.
* The length of the vector is the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> EigenvalueType;
/** \brief Type for matrix of eigenvectors as returned by eigenvectors().
*
* This is a square matrix with entries of type #ComplexScalar.
* The size is the same as the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, RowsAtCompileTime, ColsAtCompileTime, Options, MaxRowsAtCompileTime, MaxColsAtCompileTime> EigenvectorsType;
/** \brief Default constructor.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via EigenSolver::compute(const MatrixType&, bool).
*
* \sa compute() for an example.
*/
EigenSolver() : m_eivec(), m_eivalues(), m_isInitialized(false), m_realSchur(), m_matT(), m_tmp() {}
/** \brief Default constructor with memory preallocation
*
* Like the default constructor but with preallocation of the internal data
* according to the specified problem \a size.
* \sa EigenSolver()
*/
explicit EigenSolver(Index size)
: m_eivec(size, size),
m_eivalues(size),
m_isInitialized(false),
m_eigenvectorsOk(false),
m_realSchur(size),
m_matT(size, size),
m_tmp(size)
{}
/** \brief Constructor; computes eigendecomposition of given matrix.
*
* \param[in] matrix Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are
* computed.
*
* This constructor calls compute() to compute the eigenvalues
* and eigenvectors.
*
* Example: \include EigenSolver_EigenSolver_MatrixType.cpp
* Output: \verbinclude EigenSolver_EigenSolver_MatrixType.out
*
* \sa compute()
*/
template<typename InputType>
explicit EigenSolver(const EigenBase<InputType>& matrix, bool computeEigenvectors = true)
: m_eivec(matrix.rows(), matrix.cols()),
m_eivalues(matrix.cols()),
m_isInitialized(false),
m_eigenvectorsOk(false),
m_realSchur(matrix.cols()),
m_matT(matrix.rows(), matrix.cols()),
m_tmp(matrix.cols())
{
compute(matrix.derived(), computeEigenvectors);
}
/** \brief Returns the eigenvectors of given matrix.
*
* \returns %Matrix whose columns are the (possibly complex) eigenvectors.
*
* \pre Either the constructor
* EigenSolver(const MatrixType&,bool) or the member function
* compute(const MatrixType&, bool) has been called before, and
* \p computeEigenvectors was set to true (the default).
*
* Column \f$ k \f$ of the returned matrix is an eigenvector corresponding
* to eigenvalue number \f$ k \f$ as returned by eigenvalues(). The
* eigenvectors are normalized to have (Euclidean) norm equal to one. The
* matrix returned by this function is the matrix \f$ V \f$ in the
* eigendecomposition \f$ A = V D V^{-1} \f$, if it exists.
*
* Example: \include EigenSolver_eigenvectors.cpp
* Output: \verbinclude EigenSolver_eigenvectors.out
*
* \sa eigenvalues(), pseudoEigenvectors()
*/
EigenvectorsType eigenvectors() const;
/** \brief Returns the pseudo-eigenvectors of given matrix.
*
* \returns Const reference to matrix whose columns are the pseudo-eigenvectors.
*
* \pre Either the constructor
* EigenSolver(const MatrixType&,bool) or the member function
* compute(const MatrixType&, bool) has been called before, and
* \p computeEigenvectors was set to true (the default).
*
* The real matrix \f$ V \f$ returned by this function and the
* block-diagonal matrix \f$ D \f$ returned by pseudoEigenvalueMatrix()
* satisfy \f$ AV = VD \f$.
*
* Example: \include EigenSolver_pseudoEigenvectors.cpp
* Output: \verbinclude EigenSolver_pseudoEigenvectors.out
*
* \sa pseudoEigenvalueMatrix(), eigenvectors()
*/
const MatrixType& pseudoEigenvectors() const
{
eigen_assert(m_isInitialized && "EigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
return m_eivec;
}
/** \brief Returns the block-diagonal matrix in the pseudo-eigendecomposition.
*
* \returns A block-diagonal matrix.
*
* \pre Either the constructor
* EigenSolver(const MatrixType&,bool) or the member function
* compute(const MatrixType&, bool) has been called before.
*
* The matrix \f$ D \f$ returned by this function is real and
* block-diagonal. The blocks on the diagonal are either 1-by-1 or 2-by-2
* blocks of the form
* \f$ \begin{bmatrix} u & v \\ -v & u \end{bmatrix} \f$.
* These blocks are not sorted in any particular order.
* The matrix \f$ D \f$ and the matrix \f$ V \f$ returned by
* pseudoEigenvectors() satisfy \f$ AV = VD \f$.
*
* \sa pseudoEigenvectors() for an example, eigenvalues()
*/
MatrixType pseudoEigenvalueMatrix() const;
/** \brief Returns the eigenvalues of given matrix.
*
* \returns A const reference to the column vector containing the eigenvalues.
*
* \pre Either the constructor
* EigenSolver(const MatrixType&,bool) or the member function
* compute(const MatrixType&, bool) has been called before.
*
* The eigenvalues are repeated according to their algebraic multiplicity,
* so there are as many eigenvalues as rows in the matrix. The eigenvalues
* are not sorted in any particular order.
*
* Example: \include EigenSolver_eigenvalues.cpp
* Output: \verbinclude EigenSolver_eigenvalues.out
*
* \sa eigenvectors(), pseudoEigenvalueMatrix(),
* MatrixBase::eigenvalues()
*/
const EigenvalueType& eigenvalues() const
{
eigen_assert(m_isInitialized && "EigenSolver is not initialized.");
return m_eivalues;
}
/** \brief Computes eigendecomposition of given matrix.
*
* \param[in] matrix Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are
* computed.
* \returns Reference to \c *this
*
* This function computes the eigenvalues of the real matrix \p matrix.
* The eigenvalues() function can be used to retrieve them. If
* \p computeEigenvectors is true, then the eigenvectors are also computed
* and can be retrieved by calling eigenvectors().
*
* The matrix is first reduced to real Schur form using the RealSchur
* class. The Schur decomposition is then used to compute the eigenvalues
* and eigenvectors.
*
* The cost of the computation is dominated by the cost of the
* Schur decomposition, which is very approximately \f$ 25n^3 \f$
* (where \f$ n \f$ is the size of the matrix) if \p computeEigenvectors
* is true, and \f$ 10n^3 \f$ if \p computeEigenvectors is false.
*
* This method reuses of the allocated data in the EigenSolver object.
*
* Example: \include EigenSolver_compute.cpp
* Output: \verbinclude EigenSolver_compute.out
*/
template<typename InputType>
EigenSolver& compute(const EigenBase<InputType>& matrix, bool computeEigenvectors = true);
/** \returns NumericalIssue if the input contains INF or NaN values or overflow occured. Returns Success otherwise. */
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "EigenSolver is not initialized.");
return m_info;
}
/** \brief Sets the maximum number of iterations allowed. */
EigenSolver& setMaxIterations(Index maxIters)
{
m_realSchur.setMaxIterations(maxIters);
return *this;
}
/** \brief Returns the maximum number of iterations. */
Index getMaxIterations()
{
return m_realSchur.getMaxIterations();
}
private:
void doComputeEigenvectors();
protected:
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
EIGEN_STATIC_ASSERT(!NumTraits<Scalar>::IsComplex, NUMERIC_TYPE_MUST_BE_REAL);
}
MatrixType m_eivec;
EigenvalueType m_eivalues;
bool m_isInitialized;
bool m_eigenvectorsOk;
ComputationInfo m_info;
RealSchur<MatrixType> m_realSchur;
MatrixType m_matT;
typedef Matrix<Scalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> ColumnVectorType;
ColumnVectorType m_tmp;
};
template<typename MatrixType>
MatrixType EigenSolver<MatrixType>::pseudoEigenvalueMatrix() const
{
eigen_assert(m_isInitialized && "EigenSolver is not initialized.");
const RealScalar precision = RealScalar(2)*NumTraits<RealScalar>::epsilon();
Index n = m_eivalues.rows();
MatrixType matD = MatrixType::Zero(n,n);
for (Index i=0; i<n; ++i)
{
if (internal::isMuchSmallerThan(numext::imag(m_eivalues.coeff(i)), numext::real(m_eivalues.coeff(i)), precision))
matD.coeffRef(i,i) = numext::real(m_eivalues.coeff(i));
else
{
matD.template block<2,2>(i,i) << numext::real(m_eivalues.coeff(i)), numext::imag(m_eivalues.coeff(i)),
-numext::imag(m_eivalues.coeff(i)), numext::real(m_eivalues.coeff(i));
++i;
}
}
return matD;
}
template<typename MatrixType>
typename EigenSolver<MatrixType>::EigenvectorsType EigenSolver<MatrixType>::eigenvectors() const
{
eigen_assert(m_isInitialized && "EigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
const RealScalar precision = RealScalar(2)*NumTraits<RealScalar>::epsilon();
Index n = m_eivec.cols();
EigenvectorsType matV(n,n);
for (Index j=0; j<n; ++j)
{
if (internal::isMuchSmallerThan(numext::imag(m_eivalues.coeff(j)), numext::real(m_eivalues.coeff(j)), precision) || j+1==n)
{
// we have a real eigen value
matV.col(j) = m_eivec.col(j).template cast<ComplexScalar>();
matV.col(j).normalize();
}
else
{
// we have a pair of complex eigen values
for (Index i=0; i<n; ++i)
{
matV.coeffRef(i,j) = ComplexScalar(m_eivec.coeff(i,j), m_eivec.coeff(i,j+1));
matV.coeffRef(i,j+1) = ComplexScalar(m_eivec.coeff(i,j), -m_eivec.coeff(i,j+1));
}
matV.col(j).normalize();
matV.col(j+1).normalize();
++j;
}
}
return matV;
}
template<typename MatrixType>
template<typename InputType>
EigenSolver<MatrixType>&
EigenSolver<MatrixType>::compute(const EigenBase<InputType>& matrix, bool computeEigenvectors)
{
check_template_parameters();
using std::sqrt;
using std::abs;
using numext::isfinite;
eigen_assert(matrix.cols() == matrix.rows());
// Reduce to real Schur form.
m_realSchur.compute(matrix.derived(), computeEigenvectors);
m_info = m_realSchur.info();
if (m_info == Success)
{
m_matT = m_realSchur.matrixT();
if (computeEigenvectors)
m_eivec = m_realSchur.matrixU();
// Compute eigenvalues from matT
m_eivalues.resize(matrix.cols());
Index i = 0;
while (i < matrix.cols())
{
if (i == matrix.cols() - 1 || m_matT.coeff(i+1, i) == Scalar(0))
{
m_eivalues.coeffRef(i) = m_matT.coeff(i, i);
if(!(isfinite)(m_eivalues.coeffRef(i)))
{
m_isInitialized = true;
m_eigenvectorsOk = false;
m_info = NumericalIssue;
return *this;
}
++i;
}
else
{
Scalar p = Scalar(0.5) * (m_matT.coeff(i, i) - m_matT.coeff(i+1, i+1));
Scalar z;
// Compute z = sqrt(abs(p * p + m_matT.coeff(i+1, i) * m_matT.coeff(i, i+1)));
// without overflow
{
Scalar t0 = m_matT.coeff(i+1, i);
Scalar t1 = m_matT.coeff(i, i+1);
Scalar maxval = numext::maxi<Scalar>(abs(p),numext::maxi<Scalar>(abs(t0),abs(t1)));
t0 /= maxval;
t1 /= maxval;
Scalar p0 = p/maxval;
z = maxval * sqrt(abs(p0 * p0 + t0 * t1));
}
m_eivalues.coeffRef(i) = ComplexScalar(m_matT.coeff(i+1, i+1) + p, z);
m_eivalues.coeffRef(i+1) = ComplexScalar(m_matT.coeff(i+1, i+1) + p, -z);
if(!((isfinite)(m_eivalues.coeffRef(i)) && (isfinite)(m_eivalues.coeffRef(i+1))))
{
m_isInitialized = true;
m_eigenvectorsOk = false;
m_info = NumericalIssue;
return *this;
}
i += 2;
}
}
// Compute eigenvectors.
if (computeEigenvectors)
doComputeEigenvectors();
}
m_isInitialized = true;
m_eigenvectorsOk = computeEigenvectors;
return *this;
}
template<typename MatrixType>
void EigenSolver<MatrixType>::doComputeEigenvectors()
{
using std::abs;
const Index size = m_eivec.cols();
const Scalar eps = NumTraits<Scalar>::epsilon();
// inefficient! this is already computed in RealSchur
Scalar norm(0);
for (Index j = 0; j < size; ++j)
{
norm += m_matT.row(j).segment((std::max)(j-1,Index(0)), size-(std::max)(j-1,Index(0))).cwiseAbs().sum();
}
// Backsubstitute to find vectors of upper triangular form
if (norm == Scalar(0))
{
return;
}
for (Index n = size-1; n >= 0; n--)
{
Scalar p = m_eivalues.coeff(n).real();
Scalar q = m_eivalues.coeff(n).imag();
// Scalar vector
if (q == Scalar(0))
{
Scalar lastr(0), lastw(0);
Index l = n;
m_matT.coeffRef(n,n) = Scalar(1);
for (Index i = n-1; i >= 0; i--)
{
Scalar w = m_matT.coeff(i,i) - p;
Scalar r = m_matT.row(i).segment(l,n-l+1).dot(m_matT.col(n).segment(l, n-l+1));
if (m_eivalues.coeff(i).imag() < Scalar(0))
{
lastw = w;
lastr = r;
}
else
{
l = i;
if (m_eivalues.coeff(i).imag() == Scalar(0))
{
if (w != Scalar(0))
m_matT.coeffRef(i,n) = -r / w;
else
m_matT.coeffRef(i,n) = -r / (eps * norm);
}
else // Solve real equations
{
Scalar x = m_matT.coeff(i,i+1);
Scalar y = m_matT.coeff(i+1,i);
Scalar denom = (m_eivalues.coeff(i).real() - p) * (m_eivalues.coeff(i).real() - p) + m_eivalues.coeff(i).imag() * m_eivalues.coeff(i).imag();
Scalar t = (x * lastr - lastw * r) / denom;
m_matT.coeffRef(i,n) = t;
if (abs(x) > abs(lastw))
m_matT.coeffRef(i+1,n) = (-r - w * t) / x;
else
m_matT.coeffRef(i+1,n) = (-lastr - y * t) / lastw;
}
// Overflow control
Scalar t = abs(m_matT.coeff(i,n));
if ((eps * t) * t > Scalar(1))
m_matT.col(n).tail(size-i) /= t;
}
}
}
else if (q < Scalar(0) && n > 0) // Complex vector
{
Scalar lastra(0), lastsa(0), lastw(0);
Index l = n-1;
// Last vector component imaginary so matrix is triangular
if (abs(m_matT.coeff(n,n-1)) > abs(m_matT.coeff(n-1,n)))
{
m_matT.coeffRef(n-1,n-1) = q / m_matT.coeff(n,n-1);
m_matT.coeffRef(n-1,n) = -(m_matT.coeff(n,n) - p) / m_matT.coeff(n,n-1);
}
else
{
ComplexScalar cc = ComplexScalar(Scalar(0),-m_matT.coeff(n-1,n)) / ComplexScalar(m_matT.coeff(n-1,n-1)-p,q);
m_matT.coeffRef(n-1,n-1) = numext::real(cc);
m_matT.coeffRef(n-1,n) = numext::imag(cc);
}
m_matT.coeffRef(n,n-1) = Scalar(0);
m_matT.coeffRef(n,n) = Scalar(1);
for (Index i = n-2; i >= 0; i--)
{
Scalar ra = m_matT.row(i).segment(l, n-l+1).dot(m_matT.col(n-1).segment(l, n-l+1));
Scalar sa = m_matT.row(i).segment(l, n-l+1).dot(m_matT.col(n).segment(l, n-l+1));
Scalar w = m_matT.coeff(i,i) - p;
if (m_eivalues.coeff(i).imag() < Scalar(0))
{
lastw = w;
lastra = ra;
lastsa = sa;
}
else
{
l = i;
if (m_eivalues.coeff(i).imag() == RealScalar(0))
{
ComplexScalar cc = ComplexScalar(-ra,-sa) / ComplexScalar(w,q);
m_matT.coeffRef(i,n-1) = numext::real(cc);
m_matT.coeffRef(i,n) = numext::imag(cc);
}
else
{
// Solve complex equations
Scalar x = m_matT.coeff(i,i+1);
Scalar y = m_matT.coeff(i+1,i);
Scalar vr = (m_eivalues.coeff(i).real() - p) * (m_eivalues.coeff(i).real() - p) + m_eivalues.coeff(i).imag() * m_eivalues.coeff(i).imag() - q * q;
Scalar vi = (m_eivalues.coeff(i).real() - p) * Scalar(2) * q;
if ((vr == Scalar(0)) && (vi == Scalar(0)))
vr = eps * norm * (abs(w) + abs(q) + abs(x) + abs(y) + abs(lastw));
ComplexScalar cc = ComplexScalar(x*lastra-lastw*ra+q*sa,x*lastsa-lastw*sa-q*ra) / ComplexScalar(vr,vi);
m_matT.coeffRef(i,n-1) = numext::real(cc);
m_matT.coeffRef(i,n) = numext::imag(cc);
if (abs(x) > (abs(lastw) + abs(q)))
{
m_matT.coeffRef(i+1,n-1) = (-ra - w * m_matT.coeff(i,n-1) + q * m_matT.coeff(i,n)) / x;
m_matT.coeffRef(i+1,n) = (-sa - w * m_matT.coeff(i,n) - q * m_matT.coeff(i,n-1)) / x;
}
else
{
cc = ComplexScalar(-lastra-y*m_matT.coeff(i,n-1),-lastsa-y*m_matT.coeff(i,n)) / ComplexScalar(lastw,q);
m_matT.coeffRef(i+1,n-1) = numext::real(cc);
m_matT.coeffRef(i+1,n) = numext::imag(cc);
}
}
// Overflow control
Scalar t = numext::maxi<Scalar>(abs(m_matT.coeff(i,n-1)),abs(m_matT.coeff(i,n)));
if ((eps * t) * t > Scalar(1))
m_matT.block(i, n-1, size-i, 2) /= t;
}
}
// We handled a pair of complex conjugate eigenvalues, so need to skip them both
n--;
}
else
{
eigen_assert(0 && "Internal bug in EigenSolver (INF or NaN has not been detected)"); // this should not happen
}
}
// Back transformation to get eigenvectors of original matrix
for (Index j = size-1; j >= 0; j--)
{
m_tmp.noalias() = m_eivec.leftCols(j+1) * m_matT.col(j).segment(0, j+1);
m_eivec.col(j) = m_tmp;
}
}
} // end namespace Eigen
#endif // EIGEN_EIGENSOLVER_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012-2016 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010,2012 Jitse Niesen <jitse@maths.leeds.ac.uk>
// Copyright (C) 2016 Tobias Wood <tobias@spinicist.org.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_GENERALIZEDEIGENSOLVER_H
#define EIGEN_GENERALIZEDEIGENSOLVER_H
#include "./RealQZ.h"
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class GeneralizedEigenSolver
*
* \brief Computes the generalized eigenvalues and eigenvectors of a pair of general matrices
*
* \tparam _MatrixType the type of the matrices of which we are computing the
* eigen-decomposition; this is expected to be an instantiation of the Matrix
* class template. Currently, only real matrices are supported.
*
* The generalized eigenvalues and eigenvectors of a matrix pair \f$ A \f$ and \f$ B \f$ are scalars
* \f$ \lambda \f$ and vectors \f$ v \f$ such that \f$ Av = \lambda Bv \f$. If
* \f$ D \f$ is a diagonal matrix with the eigenvalues on the diagonal, and
* \f$ V \f$ is a matrix with the eigenvectors as its columns, then \f$ A V =
* B V D \f$. The matrix \f$ V \f$ is almost always invertible, in which case we
* have \f$ A = B V D V^{-1} \f$. This is called the generalized eigen-decomposition.
*
* The generalized eigenvalues and eigenvectors of a matrix pair may be complex, even when the
* matrices are real. Moreover, the generalized eigenvalue might be infinite if the matrix B is
* singular. To workaround this difficulty, the eigenvalues are provided as a pair of complex \f$ \alpha \f$
* and real \f$ \beta \f$ such that: \f$ \lambda_i = \alpha_i / \beta_i \f$. If \f$ \beta_i \f$ is (nearly) zero,
* then one can consider the well defined left eigenvalue \f$ \mu = \beta_i / \alpha_i\f$ such that:
* \f$ \mu_i A v_i = B v_i \f$, or even \f$ \mu_i u_i^T A = u_i^T B \f$ where \f$ u_i \f$ is
* called the left eigenvector.
*
* Call the function compute() to compute the generalized eigenvalues and eigenvectors of
* a given matrix pair. Alternatively, you can use the
* GeneralizedEigenSolver(const MatrixType&, const MatrixType&, bool) constructor which computes the
* eigenvalues and eigenvectors at construction time. Once the eigenvalue and
* eigenvectors are computed, they can be retrieved with the eigenvalues() and
* eigenvectors() functions.
*
* Here is an usage example of this class:
* Example: \include GeneralizedEigenSolver.cpp
* Output: \verbinclude GeneralizedEigenSolver.out
*
* \sa MatrixBase::eigenvalues(), class ComplexEigenSolver, class SelfAdjointEigenSolver
*/
template<typename _MatrixType> class GeneralizedEigenSolver
{
public:
/** \brief Synonym for the template parameter \p _MatrixType. */
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
/** \brief Scalar type for matrices of type #MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
/** \brief Complex scalar type for #MatrixType.
*
* This is \c std::complex<Scalar> if #Scalar is real (e.g.,
* \c float or \c double) and just \c Scalar if #Scalar is
* complex.
*/
typedef std::complex<RealScalar> ComplexScalar;
/** \brief Type for vector of real scalar values eigenvalues as returned by betas().
*
* This is a column vector with entries of type #Scalar.
* The length of the vector is the size of #MatrixType.
*/
typedef Matrix<Scalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> VectorType;
/** \brief Type for vector of complex scalar values eigenvalues as returned by alphas().
*
* This is a column vector with entries of type #ComplexScalar.
* The length of the vector is the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> ComplexVectorType;
/** \brief Expression type for the eigenvalues as returned by eigenvalues().
*/
typedef CwiseBinaryOp<internal::scalar_quotient_op<ComplexScalar,Scalar>,ComplexVectorType,VectorType> EigenvalueType;
/** \brief Type for matrix of eigenvectors as returned by eigenvectors().
*
* This is a square matrix with entries of type #ComplexScalar.
* The size is the same as the size of #MatrixType.
*/
typedef Matrix<ComplexScalar, RowsAtCompileTime, ColsAtCompileTime, Options, MaxRowsAtCompileTime, MaxColsAtCompileTime> EigenvectorsType;
/** \brief Default constructor.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via EigenSolver::compute(const MatrixType&, bool).
*
* \sa compute() for an example.
*/
GeneralizedEigenSolver()
: m_eivec(),
m_alphas(),
m_betas(),
m_valuesOkay(false),
m_vectorsOkay(false),
m_realQZ()
{}
/** \brief Default constructor with memory preallocation
*
* Like the default constructor but with preallocation of the internal data
* according to the specified problem \a size.
* \sa GeneralizedEigenSolver()
*/
explicit GeneralizedEigenSolver(Index size)
: m_eivec(size, size),
m_alphas(size),
m_betas(size),
m_valuesOkay(false),
m_vectorsOkay(false),
m_realQZ(size),
m_tmp(size)
{}
/** \brief Constructor; computes the generalized eigendecomposition of given matrix pair.
*
* \param[in] A Square matrix whose eigendecomposition is to be computed.
* \param[in] B Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are computed.
*
* This constructor calls compute() to compute the generalized eigenvalues
* and eigenvectors.
*
* \sa compute()
*/
GeneralizedEigenSolver(const MatrixType& A, const MatrixType& B, bool computeEigenvectors = true)
: m_eivec(A.rows(), A.cols()),
m_alphas(A.cols()),
m_betas(A.cols()),
m_valuesOkay(false),
m_vectorsOkay(false),
m_realQZ(A.cols()),
m_tmp(A.cols())
{
compute(A, B, computeEigenvectors);
}
/* \brief Returns the computed generalized eigenvectors.
*
* \returns %Matrix whose columns are the (possibly complex) right eigenvectors.
* i.e. the eigenvectors that solve (A - l*B)x = 0. The ordering matches the eigenvalues.
*
* \pre Either the constructor
* GeneralizedEigenSolver(const MatrixType&,const MatrixType&, bool) or the member function
* compute(const MatrixType&, const MatrixType& bool) has been called before, and
* \p computeEigenvectors was set to true (the default).
*
* \sa eigenvalues()
*/
EigenvectorsType eigenvectors() const {
eigen_assert(m_vectorsOkay && "Eigenvectors for GeneralizedEigenSolver were not calculated.");
return m_eivec;
}
/** \brief Returns an expression of the computed generalized eigenvalues.
*
* \returns An expression of the column vector containing the eigenvalues.
*
* It is a shortcut for \code this->alphas().cwiseQuotient(this->betas()); \endcode
* Not that betas might contain zeros. It is therefore not recommended to use this function,
* but rather directly deal with the alphas and betas vectors.
*
* \pre Either the constructor
* GeneralizedEigenSolver(const MatrixType&,const MatrixType&,bool) or the member function
* compute(const MatrixType&,const MatrixType&,bool) has been called before.
*
* The eigenvalues are repeated according to their algebraic multiplicity,
* so there are as many eigenvalues as rows in the matrix. The eigenvalues
* are not sorted in any particular order.
*
* \sa alphas(), betas(), eigenvectors()
*/
EigenvalueType eigenvalues() const
{
eigen_assert(m_valuesOkay && "GeneralizedEigenSolver is not initialized.");
return EigenvalueType(m_alphas,m_betas);
}
/** \returns A const reference to the vectors containing the alpha values
*
* This vector permits to reconstruct the j-th eigenvalues as alphas(i)/betas(j).
*
* \sa betas(), eigenvalues() */
ComplexVectorType alphas() const
{
eigen_assert(m_valuesOkay && "GeneralizedEigenSolver is not initialized.");
return m_alphas;
}
/** \returns A const reference to the vectors containing the beta values
*
* This vector permits to reconstruct the j-th eigenvalues as alphas(i)/betas(j).
*
* \sa alphas(), eigenvalues() */
VectorType betas() const
{
eigen_assert(m_valuesOkay && "GeneralizedEigenSolver is not initialized.");
return m_betas;
}
/** \brief Computes generalized eigendecomposition of given matrix.
*
* \param[in] A Square matrix whose eigendecomposition is to be computed.
* \param[in] B Square matrix whose eigendecomposition is to be computed.
* \param[in] computeEigenvectors If true, both the eigenvectors and the
* eigenvalues are computed; if false, only the eigenvalues are
* computed.
* \returns Reference to \c *this
*
* This function computes the eigenvalues of the real matrix \p matrix.
* The eigenvalues() function can be used to retrieve them. If
* \p computeEigenvectors is true, then the eigenvectors are also computed
* and can be retrieved by calling eigenvectors().
*
* The matrix is first reduced to real generalized Schur form using the RealQZ
* class. The generalized Schur decomposition is then used to compute the eigenvalues
* and eigenvectors.
*
* The cost of the computation is dominated by the cost of the
* generalized Schur decomposition.
*
* This method reuses of the allocated data in the GeneralizedEigenSolver object.
*/
GeneralizedEigenSolver& compute(const MatrixType& A, const MatrixType& B, bool computeEigenvectors = true);
ComputationInfo info() const
{
eigen_assert(m_valuesOkay && "EigenSolver is not initialized.");
return m_realQZ.info();
}
/** Sets the maximal number of iterations allowed.
*/
GeneralizedEigenSolver& setMaxIterations(Index maxIters)
{
m_realQZ.setMaxIterations(maxIters);
return *this;
}
protected:
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
EIGEN_STATIC_ASSERT(!NumTraits<Scalar>::IsComplex, NUMERIC_TYPE_MUST_BE_REAL);
}
EigenvectorsType m_eivec;
ComplexVectorType m_alphas;
VectorType m_betas;
bool m_valuesOkay, m_vectorsOkay;
RealQZ<MatrixType> m_realQZ;
ComplexVectorType m_tmp;
};
template<typename MatrixType>
GeneralizedEigenSolver<MatrixType>&
GeneralizedEigenSolver<MatrixType>::compute(const MatrixType& A, const MatrixType& B, bool computeEigenvectors)
{
check_template_parameters();
using std::sqrt;
using std::abs;
eigen_assert(A.cols() == A.rows() && B.cols() == A.rows() && B.cols() == B.rows());
Index size = A.cols();
m_valuesOkay = false;
m_vectorsOkay = false;
// Reduce to generalized real Schur form:
// A = Q S Z and B = Q T Z
m_realQZ.compute(A, B, computeEigenvectors);
if (m_realQZ.info() == Success)
{
// Resize storage
m_alphas.resize(size);
m_betas.resize(size);
if (computeEigenvectors)
{
m_eivec.resize(size,size);
m_tmp.resize(size);
}
// Aliases:
Map<VectorType> v(reinterpret_cast<Scalar*>(m_tmp.data()), size);
ComplexVectorType &cv = m_tmp;
const MatrixType &mS = m_realQZ.matrixS();
const MatrixType &mT = m_realQZ.matrixT();
Index i = 0;
while (i < size)
{
if (i == size - 1 || mS.coeff(i+1, i) == Scalar(0))
{
// Real eigenvalue
m_alphas.coeffRef(i) = mS.diagonal().coeff(i);
m_betas.coeffRef(i) = mT.diagonal().coeff(i);
if (computeEigenvectors)
{
v.setConstant(Scalar(0.0));
v.coeffRef(i) = Scalar(1.0);
// For singular eigenvalues do nothing more
if(abs(m_betas.coeffRef(i)) >= (std::numeric_limits<RealScalar>::min)())
{
// Non-singular eigenvalue
const Scalar alpha = real(m_alphas.coeffRef(i));
const Scalar beta = m_betas.coeffRef(i);
for (Index j = i-1; j >= 0; j--)
{
const Index st = j+1;
const Index sz = i-j;
if (j > 0 && mS.coeff(j, j-1) != Scalar(0))
{
// 2x2 block
Matrix<Scalar, 2, 1> rhs = (alpha*mT.template block<2,Dynamic>(j-1,st,2,sz) - beta*mS.template block<2,Dynamic>(j-1,st,2,sz)) .lazyProduct( v.segment(st,sz) );
Matrix<Scalar, 2, 2> lhs = beta * mS.template block<2,2>(j-1,j-1) - alpha * mT.template block<2,2>(j-1,j-1);
v.template segment<2>(j-1) = lhs.partialPivLu().solve(rhs);
j--;
}
else
{
v.coeffRef(j) = -v.segment(st,sz).transpose().cwiseProduct(beta*mS.block(j,st,1,sz) - alpha*mT.block(j,st,1,sz)).sum() / (beta*mS.coeffRef(j,j) - alpha*mT.coeffRef(j,j));
}
}
}
m_eivec.col(i).real().noalias() = m_realQZ.matrixZ().transpose() * v;
m_eivec.col(i).real().normalize();
m_eivec.col(i).imag().setConstant(0);
}
++i;
}
else
{
// We need to extract the generalized eigenvalues of the pair of a general 2x2 block S and a positive diagonal 2x2 block T
// Then taking beta=T_00*T_11, we can avoid any division, and alpha is the eigenvalues of A = (U^-1 * S * U) * diag(T_11,T_00):
// T = [a 0]
// [0 b]
RealScalar a = mT.diagonal().coeff(i),
b = mT.diagonal().coeff(i+1);
const RealScalar beta = m_betas.coeffRef(i) = m_betas.coeffRef(i+1) = a*b;
// ^^ NOTE: using diagonal()(i) instead of coeff(i,i) workarounds a MSVC bug.
Matrix<RealScalar,2,2> S2 = mS.template block<2,2>(i,i) * Matrix<Scalar,2,1>(b,a).asDiagonal();
Scalar p = Scalar(0.5) * (S2.coeff(0,0) - S2.coeff(1,1));
Scalar z = sqrt(abs(p * p + S2.coeff(1,0) * S2.coeff(0,1)));
const ComplexScalar alpha = ComplexScalar(S2.coeff(1,1) + p, (beta > 0) ? z : -z);
m_alphas.coeffRef(i) = conj(alpha);
m_alphas.coeffRef(i+1) = alpha;
if (computeEigenvectors) {
// Compute eigenvector in position (i+1) and then position (i) is just the conjugate
cv.setZero();
cv.coeffRef(i+1) = Scalar(1.0);
// here, the "static_cast" workaound expression template issues.
cv.coeffRef(i) = -(static_cast<Scalar>(beta*mS.coeffRef(i,i+1)) - alpha*mT.coeffRef(i,i+1))
/ (static_cast<Scalar>(beta*mS.coeffRef(i,i)) - alpha*mT.coeffRef(i,i));
for (Index j = i-1; j >= 0; j--)
{
const Index st = j+1;
const Index sz = i+1-j;
if (j > 0 && mS.coeff(j, j-1) != Scalar(0))
{
// 2x2 block
Matrix<ComplexScalar, 2, 1> rhs = (alpha*mT.template block<2,Dynamic>(j-1,st,2,sz) - beta*mS.template block<2,Dynamic>(j-1,st,2,sz)) .lazyProduct( cv.segment(st,sz) );
Matrix<ComplexScalar, 2, 2> lhs = beta * mS.template block<2,2>(j-1,j-1) - alpha * mT.template block<2,2>(j-1,j-1);
cv.template segment<2>(j-1) = lhs.partialPivLu().solve(rhs);
j--;
} else {
cv.coeffRef(j) = cv.segment(st,sz).transpose().cwiseProduct(beta*mS.block(j,st,1,sz) - alpha*mT.block(j,st,1,sz)).sum()
/ (alpha*mT.coeffRef(j,j) - static_cast<Scalar>(beta*mS.coeffRef(j,j)));
}
}
m_eivec.col(i+1).noalias() = (m_realQZ.matrixZ().transpose() * cv);
m_eivec.col(i+1).normalize();
m_eivec.col(i) = m_eivec.col(i+1).conjugate();
}
i += 2;
}
}
m_valuesOkay = true;
m_vectorsOkay = computeEigenvectors;
}
return *this;
}
} // end namespace Eigen
#endif // EIGEN_GENERALIZEDEIGENSOLVER_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_GENERALIZEDSELFADJOINTEIGENSOLVER_H
#define EIGEN_GENERALIZEDSELFADJOINTEIGENSOLVER_H
#include "./Tridiagonalization.h"
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class GeneralizedSelfAdjointEigenSolver
*
* \brief Computes eigenvalues and eigenvectors of the generalized selfadjoint eigen problem
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* eigendecomposition; this is expected to be an instantiation of the Matrix
* class template.
*
* This class solves the generalized eigenvalue problem
* \f$ Av = \lambda Bv \f$. In this case, the matrix \f$ A \f$ should be
* selfadjoint and the matrix \f$ B \f$ should be positive definite.
*
* Only the \b lower \b triangular \b part of the input matrix is referenced.
*
* Call the function compute() to compute the eigenvalues and eigenvectors of
* a given matrix. Alternatively, you can use the
* GeneralizedSelfAdjointEigenSolver(const MatrixType&, const MatrixType&, int)
* constructor which computes the eigenvalues and eigenvectors at construction time.
* Once the eigenvalue and eigenvectors are computed, they can be retrieved with the eigenvalues()
* and eigenvectors() functions.
*
* The documentation for GeneralizedSelfAdjointEigenSolver(const MatrixType&, const MatrixType&, int)
* contains an example of the typical use of this class.
*
* \sa class SelfAdjointEigenSolver, class EigenSolver, class ComplexEigenSolver
*/
template<typename _MatrixType>
class GeneralizedSelfAdjointEigenSolver : public SelfAdjointEigenSolver<_MatrixType>
{
typedef SelfAdjointEigenSolver<_MatrixType> Base;
public:
typedef _MatrixType MatrixType;
/** \brief Default constructor for fixed-size matrices.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). This constructor
* can only be used if \p _MatrixType is a fixed-size matrix; use
* GeneralizedSelfAdjointEigenSolver(Index) for dynamic-size matrices.
*/
GeneralizedSelfAdjointEigenSolver() : Base() {}
/** \brief Constructor, pre-allocates memory for dynamic-size matrices.
*
* \param [in] size Positive integer, size of the matrix whose
* eigenvalues and eigenvectors will be computed.
*
* This constructor is useful for dynamic-size matrices, when the user
* intends to perform decompositions via compute(). The \p size
* parameter is only used as a hint. It is not an error to give a wrong
* \p size, but it may impair performance.
*
* \sa compute() for an example
*/
explicit GeneralizedSelfAdjointEigenSolver(Index size)
: Base(size)
{}
/** \brief Constructor; computes generalized eigendecomposition of given matrix pencil.
*
* \param[in] matA Selfadjoint matrix in matrix pencil.
* Only the lower triangular part of the matrix is referenced.
* \param[in] matB Positive-definite matrix in matrix pencil.
* Only the lower triangular part of the matrix is referenced.
* \param[in] options A or-ed set of flags {#ComputeEigenvectors,#EigenvaluesOnly} | {#Ax_lBx,#ABx_lx,#BAx_lx}.
* Default is #ComputeEigenvectors|#Ax_lBx.
*
* This constructor calls compute(const MatrixType&, const MatrixType&, int)
* to compute the eigenvalues and (if requested) the eigenvectors of the
* generalized eigenproblem \f$ Ax = \lambda B x \f$ with \a matA the
* selfadjoint matrix \f$ A \f$ and \a matB the positive definite matrix
* \f$ B \f$. Each eigenvector \f$ x \f$ satisfies the property
* \f$ x^* B x = 1 \f$. The eigenvectors are computed if
* \a options contains ComputeEigenvectors.
*
* In addition, the two following variants can be solved via \p options:
* - \c ABx_lx: \f$ ABx = \lambda x \f$
* - \c BAx_lx: \f$ BAx = \lambda x \f$
*
* Example: \include SelfAdjointEigenSolver_SelfAdjointEigenSolver_MatrixType2.cpp
* Output: \verbinclude SelfAdjointEigenSolver_SelfAdjointEigenSolver_MatrixType2.out
*
* \sa compute(const MatrixType&, const MatrixType&, int)
*/
GeneralizedSelfAdjointEigenSolver(const MatrixType& matA, const MatrixType& matB,
int options = ComputeEigenvectors|Ax_lBx)
: Base(matA.cols())
{
compute(matA, matB, options);
}
/** \brief Computes generalized eigendecomposition of given matrix pencil.
*
* \param[in] matA Selfadjoint matrix in matrix pencil.
* Only the lower triangular part of the matrix is referenced.
* \param[in] matB Positive-definite matrix in matrix pencil.
* Only the lower triangular part of the matrix is referenced.
* \param[in] options A or-ed set of flags {#ComputeEigenvectors,#EigenvaluesOnly} | {#Ax_lBx,#ABx_lx,#BAx_lx}.
* Default is #ComputeEigenvectors|#Ax_lBx.
*
* \returns Reference to \c *this
*
* Accoring to \p options, this function computes eigenvalues and (if requested)
* the eigenvectors of one of the following three generalized eigenproblems:
* - \c Ax_lBx: \f$ Ax = \lambda B x \f$
* - \c ABx_lx: \f$ ABx = \lambda x \f$
* - \c BAx_lx: \f$ BAx = \lambda x \f$
* with \a matA the selfadjoint matrix \f$ A \f$ and \a matB the positive definite
* matrix \f$ B \f$.
* In addition, each eigenvector \f$ x \f$ satisfies the property \f$ x^* B x = 1 \f$.
*
* The eigenvalues() function can be used to retrieve
* the eigenvalues. If \p options contains ComputeEigenvectors, then the
* eigenvectors are also computed and can be retrieved by calling
* eigenvectors().
*
* The implementation uses LLT to compute the Cholesky decomposition
* \f$ B = LL^* \f$ and computes the classical eigendecomposition
* of the selfadjoint matrix \f$ L^{-1} A (L^*)^{-1} \f$ if \p options contains Ax_lBx
* and of \f$ L^{*} A L \f$ otherwise. This solves the
* generalized eigenproblem, because any solution of the generalized
* eigenproblem \f$ Ax = \lambda B x \f$ corresponds to a solution
* \f$ L^{-1} A (L^*)^{-1} (L^* x) = \lambda (L^* x) \f$ of the
* eigenproblem for \f$ L^{-1} A (L^*)^{-1} \f$. Similar statements
* can be made for the two other variants.
*
* Example: \include SelfAdjointEigenSolver_compute_MatrixType2.cpp
* Output: \verbinclude SelfAdjointEigenSolver_compute_MatrixType2.out
*
* \sa GeneralizedSelfAdjointEigenSolver(const MatrixType&, const MatrixType&, int)
*/
GeneralizedSelfAdjointEigenSolver& compute(const MatrixType& matA, const MatrixType& matB,
int options = ComputeEigenvectors|Ax_lBx);
protected:
};
template<typename MatrixType>
GeneralizedSelfAdjointEigenSolver<MatrixType>& GeneralizedSelfAdjointEigenSolver<MatrixType>::
compute(const MatrixType& matA, const MatrixType& matB, int options)
{
eigen_assert(matA.cols()==matA.rows() && matB.rows()==matA.rows() && matB.cols()==matB.rows());
eigen_assert((options&~(EigVecMask|GenEigMask))==0
&& (options&EigVecMask)!=EigVecMask
&& ((options&GenEigMask)==0 || (options&GenEigMask)==Ax_lBx
|| (options&GenEigMask)==ABx_lx || (options&GenEigMask)==BAx_lx)
&& "invalid option parameter");
bool computeEigVecs = ((options&EigVecMask)==0) || ((options&EigVecMask)==ComputeEigenvectors);
// Compute the cholesky decomposition of matB = L L' = U'U
LLT<MatrixType> cholB(matB);
int type = (options&GenEigMask);
if(type==0)
type = Ax_lBx;
if(type==Ax_lBx)
{
// compute C = inv(L) A inv(L')
MatrixType matC = matA.template selfadjointView<Lower>();
cholB.matrixL().template solveInPlace<OnTheLeft>(matC);
cholB.matrixU().template solveInPlace<OnTheRight>(matC);
Base::compute(matC, computeEigVecs ? ComputeEigenvectors : EigenvaluesOnly );
// transform back the eigen vectors: evecs = inv(U) * evecs
if(computeEigVecs)
cholB.matrixU().solveInPlace(Base::m_eivec);
}
else if(type==ABx_lx)
{
// compute C = L' A L
MatrixType matC = matA.template selfadjointView<Lower>();
matC = matC * cholB.matrixL();
matC = cholB.matrixU() * matC;
Base::compute(matC, computeEigVecs ? ComputeEigenvectors : EigenvaluesOnly);
// transform back the eigen vectors: evecs = inv(U) * evecs
if(computeEigVecs)
cholB.matrixU().solveInPlace(Base::m_eivec);
}
else if(type==BAx_lx)
{
// compute C = L' A L
MatrixType matC = matA.template selfadjointView<Lower>();
matC = matC * cholB.matrixL();
matC = cholB.matrixU() * matC;
Base::compute(matC, computeEigVecs ? ComputeEigenvectors : EigenvaluesOnly);
// transform back the eigen vectors: evecs = L * evecs
if(computeEigVecs)
Base::m_eivec = cholB.matrixL() * Base::m_eivec;
}
return *this;
}
} // end namespace Eigen
#endif // EIGEN_GENERALIZEDSELFADJOINTEIGENSOLVER_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_HESSENBERGDECOMPOSITION_H
#define EIGEN_HESSENBERGDECOMPOSITION_H
namespace Eigen {
namespace internal {
template<typename MatrixType> struct HessenbergDecompositionMatrixHReturnType;
template<typename MatrixType>
struct traits<HessenbergDecompositionMatrixHReturnType<MatrixType> >
{
typedef MatrixType ReturnType;
};
}
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class HessenbergDecomposition
*
* \brief Reduces a square matrix to Hessenberg form by an orthogonal similarity transformation
*
* \tparam _MatrixType the type of the matrix of which we are computing the Hessenberg decomposition
*
* This class performs an Hessenberg decomposition of a matrix \f$ A \f$. In
* the real case, the Hessenberg decomposition consists of an orthogonal
* matrix \f$ Q \f$ and a Hessenberg matrix \f$ H \f$ such that \f$ A = Q H
* Q^T \f$. An orthogonal matrix is a matrix whose inverse equals its
* transpose (\f$ Q^{-1} = Q^T \f$). A Hessenberg matrix has zeros below the
* subdiagonal, so it is almost upper triangular. The Hessenberg decomposition
* of a complex matrix is \f$ A = Q H Q^* \f$ with \f$ Q \f$ unitary (that is,
* \f$ Q^{-1} = Q^* \f$).
*
* Call the function compute() to compute the Hessenberg decomposition of a
* given matrix. Alternatively, you can use the
* HessenbergDecomposition(const MatrixType&) constructor which computes the
* Hessenberg decomposition at construction time. Once the decomposition is
* computed, you can use the matrixH() and matrixQ() functions to construct
* the matrices H and Q in the decomposition.
*
* The documentation for matrixH() contains an example of the typical use of
* this class.
*
* \sa class ComplexSchur, class Tridiagonalization, \ref QR_Module "QR Module"
*/
template<typename _MatrixType> class HessenbergDecomposition
{
public:
/** \brief Synonym for the template parameter \p _MatrixType. */
typedef _MatrixType MatrixType;
enum {
Size = MatrixType::RowsAtCompileTime,
SizeMinusOne = Size == Dynamic ? Dynamic : Size - 1,
Options = MatrixType::Options,
MaxSize = MatrixType::MaxRowsAtCompileTime,
MaxSizeMinusOne = MaxSize == Dynamic ? Dynamic : MaxSize - 1
};
/** \brief Scalar type for matrices of type #MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
/** \brief Type for vector of Householder coefficients.
*
* This is column vector with entries of type #Scalar. The length of the
* vector is one less than the size of #MatrixType, if it is a fixed-side
* type.
*/
typedef Matrix<Scalar, SizeMinusOne, 1, Options & ~RowMajor, MaxSizeMinusOne, 1> CoeffVectorType;
/** \brief Return type of matrixQ() */
typedef HouseholderSequence<MatrixType,typename internal::remove_all<typename CoeffVectorType::ConjugateReturnType>::type> HouseholderSequenceType;
typedef internal::HessenbergDecompositionMatrixHReturnType<MatrixType> MatrixHReturnType;
/** \brief Default constructor; the decomposition will be computed later.
*
* \param [in] size The size of the matrix whose Hessenberg decomposition will be computed.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). The \p size parameter is only
* used as a hint. It is not an error to give a wrong \p size, but it may
* impair performance.
*
* \sa compute() for an example.
*/
explicit HessenbergDecomposition(Index size = Size==Dynamic ? 2 : Size)
: m_matrix(size,size),
m_temp(size),
m_isInitialized(false)
{
if(size>1)
m_hCoeffs.resize(size-1);
}
/** \brief Constructor; computes Hessenberg decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Hessenberg decomposition is to be computed.
*
* This constructor calls compute() to compute the Hessenberg
* decomposition.
*
* \sa matrixH() for an example.
*/
template<typename InputType>
explicit HessenbergDecomposition(const EigenBase<InputType>& matrix)
: m_matrix(matrix.derived()),
m_temp(matrix.rows()),
m_isInitialized(false)
{
if(matrix.rows()<2)
{
m_isInitialized = true;
return;
}
m_hCoeffs.resize(matrix.rows()-1,1);
_compute(m_matrix, m_hCoeffs, m_temp);
m_isInitialized = true;
}
/** \brief Computes Hessenberg decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Hessenberg decomposition is to be computed.
* \returns Reference to \c *this
*
* The Hessenberg decomposition is computed by bringing the columns of the
* matrix successively in the required form using Householder reflections
* (see, e.g., Algorithm 7.4.2 in Golub \& Van Loan, <i>%Matrix
* Computations</i>). The cost is \f$ 10n^3/3 \f$ flops, where \f$ n \f$
* denotes the size of the given matrix.
*
* This method reuses of the allocated data in the HessenbergDecomposition
* object.
*
* Example: \include HessenbergDecomposition_compute.cpp
* Output: \verbinclude HessenbergDecomposition_compute.out
*/
template<typename InputType>
HessenbergDecomposition& compute(const EigenBase<InputType>& matrix)
{
m_matrix = matrix.derived();
if(matrix.rows()<2)
{
m_isInitialized = true;
return *this;
}
m_hCoeffs.resize(matrix.rows()-1,1);
_compute(m_matrix, m_hCoeffs, m_temp);
m_isInitialized = true;
return *this;
}
/** \brief Returns the Householder coefficients.
*
* \returns a const reference to the vector of Householder coefficients
*
* \pre Either the constructor HessenbergDecomposition(const MatrixType&)
* or the member function compute(const MatrixType&) has been called
* before to compute the Hessenberg decomposition of a matrix.
*
* The Householder coefficients allow the reconstruction of the matrix
* \f$ Q \f$ in the Hessenberg decomposition from the packed data.
*
* \sa packedMatrix(), \ref Householder_Module "Householder module"
*/
const CoeffVectorType& householderCoefficients() const
{
eigen_assert(m_isInitialized && "HessenbergDecomposition is not initialized.");
return m_hCoeffs;
}
/** \brief Returns the internal representation of the decomposition
*
* \returns a const reference to a matrix with the internal representation
* of the decomposition.
*
* \pre Either the constructor HessenbergDecomposition(const MatrixType&)
* or the member function compute(const MatrixType&) has been called
* before to compute the Hessenberg decomposition of a matrix.
*
* The returned matrix contains the following information:
* - the upper part and lower sub-diagonal represent the Hessenberg matrix H
* - the rest of the lower part contains the Householder vectors that, combined with
* Householder coefficients returned by householderCoefficients(),
* allows to reconstruct the matrix Q as
* \f$ Q = H_{N-1} \ldots H_1 H_0 \f$.
* Here, the matrices \f$ H_i \f$ are the Householder transformations
* \f$ H_i = (I - h_i v_i v_i^T) \f$
* where \f$ h_i \f$ is the \f$ i \f$th Householder coefficient and
* \f$ v_i \f$ is the Householder vector defined by
* \f$ v_i = [ 0, \ldots, 0, 1, M(i+2,i), \ldots, M(N-1,i) ]^T \f$
* with M the matrix returned by this function.
*
* See LAPACK for further details on this packed storage.
*
* Example: \include HessenbergDecomposition_packedMatrix.cpp
* Output: \verbinclude HessenbergDecomposition_packedMatrix.out
*
* \sa householderCoefficients()
*/
const MatrixType& packedMatrix() const
{
eigen_assert(m_isInitialized && "HessenbergDecomposition is not initialized.");
return m_matrix;
}
/** \brief Reconstructs the orthogonal matrix Q in the decomposition
*
* \returns object representing the matrix Q
*
* \pre Either the constructor HessenbergDecomposition(const MatrixType&)
* or the member function compute(const MatrixType&) has been called
* before to compute the Hessenberg decomposition of a matrix.
*
* This function returns a light-weight object of template class
* HouseholderSequence. You can either apply it directly to a matrix or
* you can convert it to a matrix of type #MatrixType.
*
* \sa matrixH() for an example, class HouseholderSequence
*/
HouseholderSequenceType matrixQ() const
{
eigen_assert(m_isInitialized && "HessenbergDecomposition is not initialized.");
return HouseholderSequenceType(m_matrix, m_hCoeffs.conjugate())
.setLength(m_matrix.rows() - 1)
.setShift(1);
}
/** \brief Constructs the Hessenberg matrix H in the decomposition
*
* \returns expression object representing the matrix H
*
* \pre Either the constructor HessenbergDecomposition(const MatrixType&)
* or the member function compute(const MatrixType&) has been called
* before to compute the Hessenberg decomposition of a matrix.
*
* The object returned by this function constructs the Hessenberg matrix H
* when it is assigned to a matrix or otherwise evaluated. The matrix H is
* constructed from the packed matrix as returned by packedMatrix(): The
* upper part (including the subdiagonal) of the packed matrix contains
* the matrix H. It may sometimes be better to directly use the packed
* matrix instead of constructing the matrix H.
*
* Example: \include HessenbergDecomposition_matrixH.cpp
* Output: \verbinclude HessenbergDecomposition_matrixH.out
*
* \sa matrixQ(), packedMatrix()
*/
MatrixHReturnType matrixH() const
{
eigen_assert(m_isInitialized && "HessenbergDecomposition is not initialized.");
return MatrixHReturnType(*this);
}
private:
typedef Matrix<Scalar, 1, Size, Options | RowMajor, 1, MaxSize> VectorType;
typedef typename NumTraits<Scalar>::Real RealScalar;
static void _compute(MatrixType& matA, CoeffVectorType& hCoeffs, VectorType& temp);
protected:
MatrixType m_matrix;
CoeffVectorType m_hCoeffs;
VectorType m_temp;
bool m_isInitialized;
};
/** \internal
* Performs a tridiagonal decomposition of \a matA in place.
*
* \param matA the input selfadjoint matrix
* \param hCoeffs returned Householder coefficients
*
* The result is written in the lower triangular part of \a matA.
*
* Implemented from Golub's "%Matrix Computations", algorithm 8.3.1.
*
* \sa packedMatrix()
*/
template<typename MatrixType>
void HessenbergDecomposition<MatrixType>::_compute(MatrixType& matA, CoeffVectorType& hCoeffs, VectorType& temp)
{
eigen_assert(matA.rows()==matA.cols());
Index n = matA.rows();
temp.resize(n);
for (Index i = 0; i<n-1; ++i)
{
// let's consider the vector v = i-th column starting at position i+1
Index remainingSize = n-i-1;
RealScalar beta;
Scalar h;
matA.col(i).tail(remainingSize).makeHouseholderInPlace(h, beta);
matA.col(i).coeffRef(i+1) = beta;
hCoeffs.coeffRef(i) = h;
// Apply similarity transformation to remaining columns,
// i.e., compute A = H A H'
// A = H A
matA.bottomRightCorner(remainingSize, remainingSize)
.applyHouseholderOnTheLeft(matA.col(i).tail(remainingSize-1), h, &temp.coeffRef(0));
// A = A H'
matA.rightCols(remainingSize)
.applyHouseholderOnTheRight(matA.col(i).tail(remainingSize-1).conjugate(), numext::conj(h), &temp.coeffRef(0));
}
}
namespace internal {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \brief Expression type for return value of HessenbergDecomposition::matrixH()
*
* \tparam MatrixType type of matrix in the Hessenberg decomposition
*
* Objects of this type represent the Hessenberg matrix in the Hessenberg
* decomposition of some matrix. The object holds a reference to the
* HessenbergDecomposition class until the it is assigned or evaluated for
* some other reason (the reference should remain valid during the life time
* of this object). This class is the return type of
* HessenbergDecomposition::matrixH(); there is probably no other use for this
* class.
*/
template<typename MatrixType> struct HessenbergDecompositionMatrixHReturnType
: public ReturnByValue<HessenbergDecompositionMatrixHReturnType<MatrixType> >
{
public:
/** \brief Constructor.
*
* \param[in] hess Hessenberg decomposition
*/
HessenbergDecompositionMatrixHReturnType(const HessenbergDecomposition<MatrixType>& hess) : m_hess(hess) { }
/** \brief Hessenberg matrix in decomposition.
*
* \param[out] result Hessenberg matrix in decomposition \p hess which
* was passed to the constructor
*/
template <typename ResultType>
inline void evalTo(ResultType& result) const
{
result = m_hess.packedMatrix();
Index n = result.rows();
if (n>2)
result.bottomLeftCorner(n-2, n-2).template triangularView<Lower>().setZero();
}
Index rows() const { return m_hess.packedMatrix().rows(); }
Index cols() const { return m_hess.packedMatrix().cols(); }
protected:
const HessenbergDecomposition<MatrixType>& m_hess;
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_HESSENBERGDECOMPOSITION_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_MATRIXBASEEIGENVALUES_H
#define EIGEN_MATRIXBASEEIGENVALUES_H
namespace Eigen {
namespace internal {
template<typename Derived, bool IsComplex>
struct eigenvalues_selector
{
// this is the implementation for the case IsComplex = true
static inline typename MatrixBase<Derived>::EigenvaluesReturnType const
run(const MatrixBase<Derived>& m)
{
typedef typename Derived::PlainObject PlainObject;
PlainObject m_eval(m);
return ComplexEigenSolver<PlainObject>(m_eval, false).eigenvalues();
}
};
template<typename Derived>
struct eigenvalues_selector<Derived, false>
{
static inline typename MatrixBase<Derived>::EigenvaluesReturnType const
run(const MatrixBase<Derived>& m)
{
typedef typename Derived::PlainObject PlainObject;
PlainObject m_eval(m);
return EigenSolver<PlainObject>(m_eval, false).eigenvalues();
}
};
} // end namespace internal
/** \brief Computes the eigenvalues of a matrix
* \returns Column vector containing the eigenvalues.
*
* \eigenvalues_module
* This function computes the eigenvalues with the help of the EigenSolver
* class (for real matrices) or the ComplexEigenSolver class (for complex
* matrices).
*
* The eigenvalues are repeated according to their algebraic multiplicity,
* so there are as many eigenvalues as rows in the matrix.
*
* The SelfAdjointView class provides a better algorithm for selfadjoint
* matrices.
*
* Example: \include MatrixBase_eigenvalues.cpp
* Output: \verbinclude MatrixBase_eigenvalues.out
*
* \sa EigenSolver::eigenvalues(), ComplexEigenSolver::eigenvalues(),
* SelfAdjointView::eigenvalues()
*/
template<typename Derived>
inline typename MatrixBase<Derived>::EigenvaluesReturnType
MatrixBase<Derived>::eigenvalues() const
{
return internal::eigenvalues_selector<Derived, NumTraits<Scalar>::IsComplex>::run(derived());
}
/** \brief Computes the eigenvalues of a matrix
* \returns Column vector containing the eigenvalues.
*
* \eigenvalues_module
* This function computes the eigenvalues with the help of the
* SelfAdjointEigenSolver class. The eigenvalues are repeated according to
* their algebraic multiplicity, so there are as many eigenvalues as rows in
* the matrix.
*
* Example: \include SelfAdjointView_eigenvalues.cpp
* Output: \verbinclude SelfAdjointView_eigenvalues.out
*
* \sa SelfAdjointEigenSolver::eigenvalues(), MatrixBase::eigenvalues()
*/
template<typename MatrixType, unsigned int UpLo>
inline typename SelfAdjointView<MatrixType, UpLo>::EigenvaluesReturnType
SelfAdjointView<MatrixType, UpLo>::eigenvalues() const
{
PlainObject thisAsMatrix(*this);
return SelfAdjointEigenSolver<PlainObject>(thisAsMatrix, false).eigenvalues();
}
/** \brief Computes the L2 operator norm
* \returns Operator norm of the matrix.
*
* \eigenvalues_module
* This function computes the L2 operator norm of a matrix, which is also
* known as the spectral norm. The norm of a matrix \f$ A \f$ is defined to be
* \f[ \|A\|_2 = \max_x \frac{\|Ax\|_2}{\|x\|_2} \f]
* where the maximum is over all vectors and the norm on the right is the
* Euclidean vector norm. The norm equals the largest singular value, which is
* the square root of the largest eigenvalue of the positive semi-definite
* matrix \f$ A^*A \f$.
*
* The current implementation uses the eigenvalues of \f$ A^*A \f$, as computed
* by SelfAdjointView::eigenvalues(), to compute the operator norm of a
* matrix. The SelfAdjointView class provides a better algorithm for
* selfadjoint matrices.
*
* Example: \include MatrixBase_operatorNorm.cpp
* Output: \verbinclude MatrixBase_operatorNorm.out
*
* \sa SelfAdjointView::eigenvalues(), SelfAdjointView::operatorNorm()
*/
template<typename Derived>
inline typename MatrixBase<Derived>::RealScalar
MatrixBase<Derived>::operatorNorm() const
{
using std::sqrt;
typename Derived::PlainObject m_eval(derived());
// FIXME if it is really guaranteed that the eigenvalues are already sorted,
// then we don't need to compute a maxCoeff() here, comparing the 1st and last ones is enough.
return sqrt((m_eval*m_eval.adjoint())
.eval()
.template selfadjointView<Lower>()
.eigenvalues()
.maxCoeff()
);
}
/** \brief Computes the L2 operator norm
* \returns Operator norm of the matrix.
*
* \eigenvalues_module
* This function computes the L2 operator norm of a self-adjoint matrix. For a
* self-adjoint matrix, the operator norm is the largest eigenvalue.
*
* The current implementation uses the eigenvalues of the matrix, as computed
* by eigenvalues(), to compute the operator norm of the matrix.
*
* Example: \include SelfAdjointView_operatorNorm.cpp
* Output: \verbinclude SelfAdjointView_operatorNorm.out
*
* \sa eigenvalues(), MatrixBase::operatorNorm()
*/
template<typename MatrixType, unsigned int UpLo>
inline typename SelfAdjointView<MatrixType, UpLo>::RealScalar
SelfAdjointView<MatrixType, UpLo>::operatorNorm() const
{
return eigenvalues().cwiseAbs().maxCoeff();
}
} // end namespace Eigen
#endif

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Alexey Korepanov <kaikaikai@yandex.ru>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_REAL_QZ_H
#define EIGEN_REAL_QZ_H
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class RealQZ
*
* \brief Performs a real QZ decomposition of a pair of square matrices
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* real QZ decomposition; this is expected to be an instantiation of the
* Matrix class template.
*
* Given a real square matrices A and B, this class computes the real QZ
* decomposition: \f$ A = Q S Z \f$, \f$ B = Q T Z \f$ where Q and Z are
* real orthogonal matrixes, T is upper-triangular matrix, and S is upper
* quasi-triangular matrix. An orthogonal matrix is a matrix whose
* inverse is equal to its transpose, \f$ U^{-1} = U^T \f$. A quasi-triangular
* matrix is a block-triangular matrix whose diagonal consists of 1-by-1
* blocks and 2-by-2 blocks where further reduction is impossible due to
* complex eigenvalues.
*
* The eigenvalues of the pencil \f$ A - z B \f$ can be obtained from
* 1x1 and 2x2 blocks on the diagonals of S and T.
*
* Call the function compute() to compute the real QZ decomposition of a
* given pair of matrices. Alternatively, you can use the
* RealQZ(const MatrixType& B, const MatrixType& B, bool computeQZ)
* constructor which computes the real QZ decomposition at construction
* time. Once the decomposition is computed, you can use the matrixS(),
* matrixT(), matrixQ() and matrixZ() functions to retrieve the matrices
* S, T, Q and Z in the decomposition. If computeQZ==false, some time
* is saved by not computing matrices Q and Z.
*
* Example: \include RealQZ_compute.cpp
* Output: \include RealQZ_compute.out
*
* \note The implementation is based on the algorithm in "Matrix Computations"
* by Gene H. Golub and Charles F. Van Loan, and a paper "An algorithm for
* generalized eigenvalue problems" by C.B.Moler and G.W.Stewart.
*
* \sa class RealSchur, class ComplexSchur, class EigenSolver, class ComplexEigenSolver
*/
template<typename _MatrixType> class RealQZ
{
public:
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
typedef typename MatrixType::Scalar Scalar;
typedef std::complex<typename NumTraits<Scalar>::Real> ComplexScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
typedef Matrix<ComplexScalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> EigenvalueType;
typedef Matrix<Scalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> ColumnVectorType;
/** \brief Default constructor.
*
* \param [in] size Positive integer, size of the matrix whose QZ decomposition will be computed.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). The \p size parameter is only
* used as a hint. It is not an error to give a wrong \p size, but it may
* impair performance.
*
* \sa compute() for an example.
*/
explicit RealQZ(Index size = RowsAtCompileTime==Dynamic ? 1 : RowsAtCompileTime) :
m_S(size, size),
m_T(size, size),
m_Q(size, size),
m_Z(size, size),
m_workspace(size*2),
m_maxIters(400),
m_isInitialized(false)
{ }
/** \brief Constructor; computes real QZ decomposition of given matrices
*
* \param[in] A Matrix A.
* \param[in] B Matrix B.
* \param[in] computeQZ If false, A and Z are not computed.
*
* This constructor calls compute() to compute the QZ decomposition.
*/
RealQZ(const MatrixType& A, const MatrixType& B, bool computeQZ = true) :
m_S(A.rows(),A.cols()),
m_T(A.rows(),A.cols()),
m_Q(A.rows(),A.cols()),
m_Z(A.rows(),A.cols()),
m_workspace(A.rows()*2),
m_maxIters(400),
m_isInitialized(false) {
compute(A, B, computeQZ);
}
/** \brief Returns matrix Q in the QZ decomposition.
*
* \returns A const reference to the matrix Q.
*/
const MatrixType& matrixQ() const {
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
eigen_assert(m_computeQZ && "The matrices Q and Z have not been computed during the QZ decomposition.");
return m_Q;
}
/** \brief Returns matrix Z in the QZ decomposition.
*
* \returns A const reference to the matrix Z.
*/
const MatrixType& matrixZ() const {
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
eigen_assert(m_computeQZ && "The matrices Q and Z have not been computed during the QZ decomposition.");
return m_Z;
}
/** \brief Returns matrix S in the QZ decomposition.
*
* \returns A const reference to the matrix S.
*/
const MatrixType& matrixS() const {
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
return m_S;
}
/** \brief Returns matrix S in the QZ decomposition.
*
* \returns A const reference to the matrix S.
*/
const MatrixType& matrixT() const {
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
return m_T;
}
/** \brief Computes QZ decomposition of given matrix.
*
* \param[in] A Matrix A.
* \param[in] B Matrix B.
* \param[in] computeQZ If false, A and Z are not computed.
* \returns Reference to \c *this
*/
RealQZ& compute(const MatrixType& A, const MatrixType& B, bool computeQZ = true);
/** \brief Reports whether previous computation was successful.
*
* \returns \c Success if computation was succesful, \c NoConvergence otherwise.
*/
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
return m_info;
}
/** \brief Returns number of performed QR-like iterations.
*/
Index iterations() const
{
eigen_assert(m_isInitialized && "RealQZ is not initialized.");
return m_global_iter;
}
/** Sets the maximal number of iterations allowed to converge to one eigenvalue
* or decouple the problem.
*/
RealQZ& setMaxIterations(Index maxIters)
{
m_maxIters = maxIters;
return *this;
}
private:
MatrixType m_S, m_T, m_Q, m_Z;
Matrix<Scalar,Dynamic,1> m_workspace;
ComputationInfo m_info;
Index m_maxIters;
bool m_isInitialized;
bool m_computeQZ;
Scalar m_normOfT, m_normOfS;
Index m_global_iter;
typedef Matrix<Scalar,3,1> Vector3s;
typedef Matrix<Scalar,2,1> Vector2s;
typedef Matrix<Scalar,2,2> Matrix2s;
typedef JacobiRotation<Scalar> JRs;
void hessenbergTriangular();
void computeNorms();
Index findSmallSubdiagEntry(Index iu);
Index findSmallDiagEntry(Index f, Index l);
void splitOffTwoRows(Index i);
void pushDownZero(Index z, Index f, Index l);
void step(Index f, Index l, Index iter);
}; // RealQZ
/** \internal Reduces S and T to upper Hessenberg - triangular form */
template<typename MatrixType>
void RealQZ<MatrixType>::hessenbergTriangular()
{
const Index dim = m_S.cols();
// perform QR decomposition of T, overwrite T with R, save Q
HouseholderQR<MatrixType> qrT(m_T);
m_T = qrT.matrixQR();
m_T.template triangularView<StrictlyLower>().setZero();
m_Q = qrT.householderQ();
// overwrite S with Q* S
m_S.applyOnTheLeft(m_Q.adjoint());
// init Z as Identity
if (m_computeQZ)
m_Z = MatrixType::Identity(dim,dim);
// reduce S to upper Hessenberg with Givens rotations
for (Index j=0; j<=dim-3; j++) {
for (Index i=dim-1; i>=j+2; i--) {
JRs G;
// kill S(i,j)
if(m_S.coeff(i,j) != 0)
{
G.makeGivens(m_S.coeff(i-1,j), m_S.coeff(i,j), &m_S.coeffRef(i-1, j));
m_S.coeffRef(i,j) = Scalar(0.0);
m_S.rightCols(dim-j-1).applyOnTheLeft(i-1,i,G.adjoint());
m_T.rightCols(dim-i+1).applyOnTheLeft(i-1,i,G.adjoint());
// update Q
if (m_computeQZ)
m_Q.applyOnTheRight(i-1,i,G);
}
// kill T(i,i-1)
if(m_T.coeff(i,i-1)!=Scalar(0))
{
G.makeGivens(m_T.coeff(i,i), m_T.coeff(i,i-1), &m_T.coeffRef(i,i));
m_T.coeffRef(i,i-1) = Scalar(0.0);
m_S.applyOnTheRight(i,i-1,G);
m_T.topRows(i).applyOnTheRight(i,i-1,G);
// update Z
if (m_computeQZ)
m_Z.applyOnTheLeft(i,i-1,G.adjoint());
}
}
}
}
/** \internal Computes vector L1 norms of S and T when in Hessenberg-Triangular form already */
template<typename MatrixType>
inline void RealQZ<MatrixType>::computeNorms()
{
const Index size = m_S.cols();
m_normOfS = Scalar(0.0);
m_normOfT = Scalar(0.0);
for (Index j = 0; j < size; ++j)
{
m_normOfS += m_S.col(j).segment(0, (std::min)(size,j+2)).cwiseAbs().sum();
m_normOfT += m_T.row(j).segment(j, size - j).cwiseAbs().sum();
}
}
/** \internal Look for single small sub-diagonal element S(res, res-1) and return res (or 0) */
template<typename MatrixType>
inline Index RealQZ<MatrixType>::findSmallSubdiagEntry(Index iu)
{
using std::abs;
Index res = iu;
while (res > 0)
{
Scalar s = abs(m_S.coeff(res-1,res-1)) + abs(m_S.coeff(res,res));
if (s == Scalar(0.0))
s = m_normOfS;
if (abs(m_S.coeff(res,res-1)) < NumTraits<Scalar>::epsilon() * s)
break;
res--;
}
return res;
}
/** \internal Look for single small diagonal element T(res, res) for res between f and l, and return res (or f-1) */
template<typename MatrixType>
inline Index RealQZ<MatrixType>::findSmallDiagEntry(Index f, Index l)
{
using std::abs;
Index res = l;
while (res >= f) {
if (abs(m_T.coeff(res,res)) <= NumTraits<Scalar>::epsilon() * m_normOfT)
break;
res--;
}
return res;
}
/** \internal decouple 2x2 diagonal block in rows i, i+1 if eigenvalues are real */
template<typename MatrixType>
inline void RealQZ<MatrixType>::splitOffTwoRows(Index i)
{
using std::abs;
using std::sqrt;
const Index dim=m_S.cols();
if (abs(m_S.coeff(i+1,i))==Scalar(0))
return;
Index j = findSmallDiagEntry(i,i+1);
if (j==i-1)
{
// block of (S T^{-1})
Matrix2s STi = m_T.template block<2,2>(i,i).template triangularView<Upper>().
template solve<OnTheRight>(m_S.template block<2,2>(i,i));
Scalar p = Scalar(0.5)*(STi(0,0)-STi(1,1));
Scalar q = p*p + STi(1,0)*STi(0,1);
if (q>=0) {
Scalar z = sqrt(q);
// one QR-like iteration for ABi - lambda I
// is enough - when we know exact eigenvalue in advance,
// convergence is immediate
JRs G;
if (p>=0)
G.makeGivens(p + z, STi(1,0));
else
G.makeGivens(p - z, STi(1,0));
m_S.rightCols(dim-i).applyOnTheLeft(i,i+1,G.adjoint());
m_T.rightCols(dim-i).applyOnTheLeft(i,i+1,G.adjoint());
// update Q
if (m_computeQZ)
m_Q.applyOnTheRight(i,i+1,G);
G.makeGivens(m_T.coeff(i+1,i+1), m_T.coeff(i+1,i));
m_S.topRows(i+2).applyOnTheRight(i+1,i,G);
m_T.topRows(i+2).applyOnTheRight(i+1,i,G);
// update Z
if (m_computeQZ)
m_Z.applyOnTheLeft(i+1,i,G.adjoint());
m_S.coeffRef(i+1,i) = Scalar(0.0);
m_T.coeffRef(i+1,i) = Scalar(0.0);
}
}
else
{
pushDownZero(j,i,i+1);
}
}
/** \internal use zero in T(z,z) to zero S(l,l-1), working in block f..l */
template<typename MatrixType>
inline void RealQZ<MatrixType>::pushDownZero(Index z, Index f, Index l)
{
JRs G;
const Index dim = m_S.cols();
for (Index zz=z; zz<l; zz++)
{
// push 0 down
Index firstColS = zz>f ? (zz-1) : zz;
G.makeGivens(m_T.coeff(zz, zz+1), m_T.coeff(zz+1, zz+1));
m_S.rightCols(dim-firstColS).applyOnTheLeft(zz,zz+1,G.adjoint());
m_T.rightCols(dim-zz).applyOnTheLeft(zz,zz+1,G.adjoint());
m_T.coeffRef(zz+1,zz+1) = Scalar(0.0);
// update Q
if (m_computeQZ)
m_Q.applyOnTheRight(zz,zz+1,G);
// kill S(zz+1, zz-1)
if (zz>f)
{
G.makeGivens(m_S.coeff(zz+1, zz), m_S.coeff(zz+1,zz-1));
m_S.topRows(zz+2).applyOnTheRight(zz, zz-1,G);
m_T.topRows(zz+1).applyOnTheRight(zz, zz-1,G);
m_S.coeffRef(zz+1,zz-1) = Scalar(0.0);
// update Z
if (m_computeQZ)
m_Z.applyOnTheLeft(zz,zz-1,G.adjoint());
}
}
// finally kill S(l,l-1)
G.makeGivens(m_S.coeff(l,l), m_S.coeff(l,l-1));
m_S.applyOnTheRight(l,l-1,G);
m_T.applyOnTheRight(l,l-1,G);
m_S.coeffRef(l,l-1)=Scalar(0.0);
// update Z
if (m_computeQZ)
m_Z.applyOnTheLeft(l,l-1,G.adjoint());
}
/** \internal QR-like iterative step for block f..l */
template<typename MatrixType>
inline void RealQZ<MatrixType>::step(Index f, Index l, Index iter)
{
using std::abs;
const Index dim = m_S.cols();
// x, y, z
Scalar x, y, z;
if (iter==10)
{
// Wilkinson ad hoc shift
const Scalar
a11=m_S.coeff(f+0,f+0), a12=m_S.coeff(f+0,f+1),
a21=m_S.coeff(f+1,f+0), a22=m_S.coeff(f+1,f+1), a32=m_S.coeff(f+2,f+1),
b12=m_T.coeff(f+0,f+1),
b11i=Scalar(1.0)/m_T.coeff(f+0,f+0),
b22i=Scalar(1.0)/m_T.coeff(f+1,f+1),
a87=m_S.coeff(l-1,l-2),
a98=m_S.coeff(l-0,l-1),
b77i=Scalar(1.0)/m_T.coeff(l-2,l-2),
b88i=Scalar(1.0)/m_T.coeff(l-1,l-1);
Scalar ss = abs(a87*b77i) + abs(a98*b88i),
lpl = Scalar(1.5)*ss,
ll = ss*ss;
x = ll + a11*a11*b11i*b11i - lpl*a11*b11i + a12*a21*b11i*b22i
- a11*a21*b12*b11i*b11i*b22i;
y = a11*a21*b11i*b11i - lpl*a21*b11i + a21*a22*b11i*b22i
- a21*a21*b12*b11i*b11i*b22i;
z = a21*a32*b11i*b22i;
}
else if (iter==16)
{
// another exceptional shift
x = m_S.coeff(f,f)/m_T.coeff(f,f)-m_S.coeff(l,l)/m_T.coeff(l,l) + m_S.coeff(l,l-1)*m_T.coeff(l-1,l) /
(m_T.coeff(l-1,l-1)*m_T.coeff(l,l));
y = m_S.coeff(f+1,f)/m_T.coeff(f,f);
z = 0;
}
else if (iter>23 && !(iter%8))
{
// extremely exceptional shift
x = internal::random<Scalar>(-1.0,1.0);
y = internal::random<Scalar>(-1.0,1.0);
z = internal::random<Scalar>(-1.0,1.0);
}
else
{
// Compute the shifts: (x,y,z,0...) = (AB^-1 - l1 I) (AB^-1 - l2 I) e1
// where l1 and l2 are the eigenvalues of the 2x2 matrix C = U V^-1 where
// U and V are 2x2 bottom right sub matrices of A and B. Thus:
// = AB^-1AB^-1 + l1 l2 I - (l1+l2)(AB^-1)
// = AB^-1AB^-1 + det(M) - tr(M)(AB^-1)
// Since we are only interested in having x, y, z with a correct ratio, we have:
const Scalar
a11 = m_S.coeff(f,f), a12 = m_S.coeff(f,f+1),
a21 = m_S.coeff(f+1,f), a22 = m_S.coeff(f+1,f+1),
a32 = m_S.coeff(f+2,f+1),
a88 = m_S.coeff(l-1,l-1), a89 = m_S.coeff(l-1,l),
a98 = m_S.coeff(l,l-1), a99 = m_S.coeff(l,l),
b11 = m_T.coeff(f,f), b12 = m_T.coeff(f,f+1),
b22 = m_T.coeff(f+1,f+1),
b88 = m_T.coeff(l-1,l-1), b89 = m_T.coeff(l-1,l),
b99 = m_T.coeff(l,l);
x = ( (a88/b88 - a11/b11)*(a99/b99 - a11/b11) - (a89/b99)*(a98/b88) + (a98/b88)*(b89/b99)*(a11/b11) ) * (b11/a21)
+ a12/b22 - (a11/b11)*(b12/b22);
y = (a22/b22-a11/b11) - (a21/b11)*(b12/b22) - (a88/b88-a11/b11) - (a99/b99-a11/b11) + (a98/b88)*(b89/b99);
z = a32/b22;
}
JRs G;
for (Index k=f; k<=l-2; k++)
{
// variables for Householder reflections
Vector2s essential2;
Scalar tau, beta;
Vector3s hr(x,y,z);
// Q_k to annihilate S(k+1,k-1) and S(k+2,k-1)
hr.makeHouseholderInPlace(tau, beta);
essential2 = hr.template bottomRows<2>();
Index fc=(std::max)(k-1,Index(0)); // first col to update
m_S.template middleRows<3>(k).rightCols(dim-fc).applyHouseholderOnTheLeft(essential2, tau, m_workspace.data());
m_T.template middleRows<3>(k).rightCols(dim-fc).applyHouseholderOnTheLeft(essential2, tau, m_workspace.data());
if (m_computeQZ)
m_Q.template middleCols<3>(k).applyHouseholderOnTheRight(essential2, tau, m_workspace.data());
if (k>f)
m_S.coeffRef(k+2,k-1) = m_S.coeffRef(k+1,k-1) = Scalar(0.0);
// Z_{k1} to annihilate T(k+2,k+1) and T(k+2,k)
hr << m_T.coeff(k+2,k+2),m_T.coeff(k+2,k),m_T.coeff(k+2,k+1);
hr.makeHouseholderInPlace(tau, beta);
essential2 = hr.template bottomRows<2>();
{
Index lr = (std::min)(k+4,dim); // last row to update
Map<Matrix<Scalar,Dynamic,1> > tmp(m_workspace.data(),lr);
// S
tmp = m_S.template middleCols<2>(k).topRows(lr) * essential2;
tmp += m_S.col(k+2).head(lr);
m_S.col(k+2).head(lr) -= tau*tmp;
m_S.template middleCols<2>(k).topRows(lr) -= (tau*tmp) * essential2.adjoint();
// T
tmp = m_T.template middleCols<2>(k).topRows(lr) * essential2;
tmp += m_T.col(k+2).head(lr);
m_T.col(k+2).head(lr) -= tau*tmp;
m_T.template middleCols<2>(k).topRows(lr) -= (tau*tmp) * essential2.adjoint();
}
if (m_computeQZ)
{
// Z
Map<Matrix<Scalar,1,Dynamic> > tmp(m_workspace.data(),dim);
tmp = essential2.adjoint()*(m_Z.template middleRows<2>(k));
tmp += m_Z.row(k+2);
m_Z.row(k+2) -= tau*tmp;
m_Z.template middleRows<2>(k) -= essential2 * (tau*tmp);
}
m_T.coeffRef(k+2,k) = m_T.coeffRef(k+2,k+1) = Scalar(0.0);
// Z_{k2} to annihilate T(k+1,k)
G.makeGivens(m_T.coeff(k+1,k+1), m_T.coeff(k+1,k));
m_S.applyOnTheRight(k+1,k,G);
m_T.applyOnTheRight(k+1,k,G);
// update Z
if (m_computeQZ)
m_Z.applyOnTheLeft(k+1,k,G.adjoint());
m_T.coeffRef(k+1,k) = Scalar(0.0);
// update x,y,z
x = m_S.coeff(k+1,k);
y = m_S.coeff(k+2,k);
if (k < l-2)
z = m_S.coeff(k+3,k);
} // loop over k
// Q_{n-1} to annihilate y = S(l,l-2)
G.makeGivens(x,y);
m_S.applyOnTheLeft(l-1,l,G.adjoint());
m_T.applyOnTheLeft(l-1,l,G.adjoint());
if (m_computeQZ)
m_Q.applyOnTheRight(l-1,l,G);
m_S.coeffRef(l,l-2) = Scalar(0.0);
// Z_{n-1} to annihilate T(l,l-1)
G.makeGivens(m_T.coeff(l,l),m_T.coeff(l,l-1));
m_S.applyOnTheRight(l,l-1,G);
m_T.applyOnTheRight(l,l-1,G);
if (m_computeQZ)
m_Z.applyOnTheLeft(l,l-1,G.adjoint());
m_T.coeffRef(l,l-1) = Scalar(0.0);
}
template<typename MatrixType>
RealQZ<MatrixType>& RealQZ<MatrixType>::compute(const MatrixType& A_in, const MatrixType& B_in, bool computeQZ)
{
const Index dim = A_in.cols();
eigen_assert (A_in.rows()==dim && A_in.cols()==dim
&& B_in.rows()==dim && B_in.cols()==dim
&& "Need square matrices of the same dimension");
m_isInitialized = true;
m_computeQZ = computeQZ;
m_S = A_in; m_T = B_in;
m_workspace.resize(dim*2);
m_global_iter = 0;
// entrance point: hessenberg triangular decomposition
hessenbergTriangular();
// compute L1 vector norms of T, S into m_normOfS, m_normOfT
computeNorms();
Index l = dim-1,
f,
local_iter = 0;
while (l>0 && local_iter<m_maxIters)
{
f = findSmallSubdiagEntry(l);
// now rows and columns f..l (including) decouple from the rest of the problem
if (f>0) m_S.coeffRef(f,f-1) = Scalar(0.0);
if (f == l) // One root found
{
l--;
local_iter = 0;
}
else if (f == l-1) // Two roots found
{
splitOffTwoRows(f);
l -= 2;
local_iter = 0;
}
else // No convergence yet
{
// if there's zero on diagonal of T, we can isolate an eigenvalue with Givens rotations
Index z = findSmallDiagEntry(f,l);
if (z>=f)
{
// zero found
pushDownZero(z,f,l);
}
else
{
// We are sure now that S.block(f,f, l-f+1,l-f+1) is underuced upper-Hessenberg
// and T.block(f,f, l-f+1,l-f+1) is invertible uper-triangular, which allows to
// apply a QR-like iteration to rows and columns f..l.
step(f,l, local_iter);
local_iter++;
m_global_iter++;
}
}
}
// check if we converged before reaching iterations limit
m_info = (local_iter<m_maxIters) ? Success : NoConvergence;
// For each non triangular 2x2 diagonal block of S,
// reduce the respective 2x2 diagonal block of T to positive diagonal form using 2x2 SVD.
// This step is not mandatory for QZ, but it does help further extraction of eigenvalues/eigenvectors,
// and is in par with Lapack/Matlab QZ.
if(m_info==Success)
{
for(Index i=0; i<dim-1; ++i)
{
if(m_S.coeff(i+1, i) != Scalar(0))
{
JacobiRotation<Scalar> j_left, j_right;
internal::real_2x2_jacobi_svd(m_T, i, i+1, &j_left, &j_right);
// Apply resulting Jacobi rotations
m_S.applyOnTheLeft(i,i+1,j_left);
m_S.applyOnTheRight(i,i+1,j_right);
m_T.applyOnTheLeft(i,i+1,j_left);
m_T.applyOnTheRight(i,i+1,j_right);
m_T(i+1,i) = m_T(i,i+1) = Scalar(0);
if(m_computeQZ) {
m_Q.applyOnTheRight(i,i+1,j_left.transpose());
m_Z.applyOnTheLeft(i,i+1,j_right.transpose());
}
i++;
}
}
}
return *this;
} // end compute
} // end namespace Eigen
#endif //EIGEN_REAL_QZ

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@@ -0,0 +1,546 @@
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010,2012 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_REAL_SCHUR_H
#define EIGEN_REAL_SCHUR_H
#include "./HessenbergDecomposition.h"
namespace Eigen {
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class RealSchur
*
* \brief Performs a real Schur decomposition of a square matrix
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* real Schur decomposition; this is expected to be an instantiation of the
* Matrix class template.
*
* Given a real square matrix A, this class computes the real Schur
* decomposition: \f$ A = U T U^T \f$ where U is a real orthogonal matrix and
* T is a real quasi-triangular matrix. An orthogonal matrix is a matrix whose
* inverse is equal to its transpose, \f$ U^{-1} = U^T \f$. A quasi-triangular
* matrix is a block-triangular matrix whose diagonal consists of 1-by-1
* blocks and 2-by-2 blocks with complex eigenvalues. The eigenvalues of the
* blocks on the diagonal of T are the same as the eigenvalues of the matrix
* A, and thus the real Schur decomposition is used in EigenSolver to compute
* the eigendecomposition of a matrix.
*
* Call the function compute() to compute the real Schur decomposition of a
* given matrix. Alternatively, you can use the RealSchur(const MatrixType&, bool)
* constructor which computes the real Schur decomposition at construction
* time. Once the decomposition is computed, you can use the matrixU() and
* matrixT() functions to retrieve the matrices U and T in the decomposition.
*
* The documentation of RealSchur(const MatrixType&, bool) contains an example
* of the typical use of this class.
*
* \note The implementation is adapted from
* <a href="http://math.nist.gov/javanumerics/jama/">JAMA</a> (public domain).
* Their code is based on EISPACK.
*
* \sa class ComplexSchur, class EigenSolver, class ComplexEigenSolver
*/
template<typename _MatrixType> class RealSchur
{
public:
typedef _MatrixType MatrixType;
enum {
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
typedef typename MatrixType::Scalar Scalar;
typedef std::complex<typename NumTraits<Scalar>::Real> ComplexScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
typedef Matrix<ComplexScalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> EigenvalueType;
typedef Matrix<Scalar, ColsAtCompileTime, 1, Options & ~RowMajor, MaxColsAtCompileTime, 1> ColumnVectorType;
/** \brief Default constructor.
*
* \param [in] size Positive integer, size of the matrix whose Schur decomposition will be computed.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). The \p size parameter is only
* used as a hint. It is not an error to give a wrong \p size, but it may
* impair performance.
*
* \sa compute() for an example.
*/
explicit RealSchur(Index size = RowsAtCompileTime==Dynamic ? 1 : RowsAtCompileTime)
: m_matT(size, size),
m_matU(size, size),
m_workspaceVector(size),
m_hess(size),
m_isInitialized(false),
m_matUisUptodate(false),
m_maxIters(-1)
{ }
/** \brief Constructor; computes real Schur decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Schur decomposition is to be computed.
* \param[in] computeU If true, both T and U are computed; if false, only T is computed.
*
* This constructor calls compute() to compute the Schur decomposition.
*
* Example: \include RealSchur_RealSchur_MatrixType.cpp
* Output: \verbinclude RealSchur_RealSchur_MatrixType.out
*/
template<typename InputType>
explicit RealSchur(const EigenBase<InputType>& matrix, bool computeU = true)
: m_matT(matrix.rows(),matrix.cols()),
m_matU(matrix.rows(),matrix.cols()),
m_workspaceVector(matrix.rows()),
m_hess(matrix.rows()),
m_isInitialized(false),
m_matUisUptodate(false),
m_maxIters(-1)
{
compute(matrix.derived(), computeU);
}
/** \brief Returns the orthogonal matrix in the Schur decomposition.
*
* \returns A const reference to the matrix U.
*
* \pre Either the constructor RealSchur(const MatrixType&, bool) or the
* member function compute(const MatrixType&, bool) has been called before
* to compute the Schur decomposition of a matrix, and \p computeU was set
* to true (the default value).
*
* \sa RealSchur(const MatrixType&, bool) for an example
*/
const MatrixType& matrixU() const
{
eigen_assert(m_isInitialized && "RealSchur is not initialized.");
eigen_assert(m_matUisUptodate && "The matrix U has not been computed during the RealSchur decomposition.");
return m_matU;
}
/** \brief Returns the quasi-triangular matrix in the Schur decomposition.
*
* \returns A const reference to the matrix T.
*
* \pre Either the constructor RealSchur(const MatrixType&, bool) or the
* member function compute(const MatrixType&, bool) has been called before
* to compute the Schur decomposition of a matrix.
*
* \sa RealSchur(const MatrixType&, bool) for an example
*/
const MatrixType& matrixT() const
{
eigen_assert(m_isInitialized && "RealSchur is not initialized.");
return m_matT;
}
/** \brief Computes Schur decomposition of given matrix.
*
* \param[in] matrix Square matrix whose Schur decomposition is to be computed.
* \param[in] computeU If true, both T and U are computed; if false, only T is computed.
* \returns Reference to \c *this
*
* The Schur decomposition is computed by first reducing the matrix to
* Hessenberg form using the class HessenbergDecomposition. The Hessenberg
* matrix is then reduced to triangular form by performing Francis QR
* iterations with implicit double shift. The cost of computing the Schur
* decomposition depends on the number of iterations; as a rough guide, it
* may be taken to be \f$25n^3\f$ flops if \a computeU is true and
* \f$10n^3\f$ flops if \a computeU is false.
*
* Example: \include RealSchur_compute.cpp
* Output: \verbinclude RealSchur_compute.out
*
* \sa compute(const MatrixType&, bool, Index)
*/
template<typename InputType>
RealSchur& compute(const EigenBase<InputType>& matrix, bool computeU = true);
/** \brief Computes Schur decomposition of a Hessenberg matrix H = Z T Z^T
* \param[in] matrixH Matrix in Hessenberg form H
* \param[in] matrixQ orthogonal matrix Q that transform a matrix A to H : A = Q H Q^T
* \param computeU Computes the matriX U of the Schur vectors
* \return Reference to \c *this
*
* This routine assumes that the matrix is already reduced in Hessenberg form matrixH
* using either the class HessenbergDecomposition or another mean.
* It computes the upper quasi-triangular matrix T of the Schur decomposition of H
* When computeU is true, this routine computes the matrix U such that
* A = U T U^T = (QZ) T (QZ)^T = Q H Q^T where A is the initial matrix
*
* NOTE Q is referenced if computeU is true; so, if the initial orthogonal matrix
* is not available, the user should give an identity matrix (Q.setIdentity())
*
* \sa compute(const MatrixType&, bool)
*/
template<typename HessMatrixType, typename OrthMatrixType>
RealSchur& computeFromHessenberg(const HessMatrixType& matrixH, const OrthMatrixType& matrixQ, bool computeU);
/** \brief Reports whether previous computation was successful.
*
* \returns \c Success if computation was succesful, \c NoConvergence otherwise.
*/
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "RealSchur is not initialized.");
return m_info;
}
/** \brief Sets the maximum number of iterations allowed.
*
* If not specified by the user, the maximum number of iterations is m_maxIterationsPerRow times the size
* of the matrix.
*/
RealSchur& setMaxIterations(Index maxIters)
{
m_maxIters = maxIters;
return *this;
}
/** \brief Returns the maximum number of iterations. */
Index getMaxIterations()
{
return m_maxIters;
}
/** \brief Maximum number of iterations per row.
*
* If not otherwise specified, the maximum number of iterations is this number times the size of the
* matrix. It is currently set to 40.
*/
static const int m_maxIterationsPerRow = 40;
private:
MatrixType m_matT;
MatrixType m_matU;
ColumnVectorType m_workspaceVector;
HessenbergDecomposition<MatrixType> m_hess;
ComputationInfo m_info;
bool m_isInitialized;
bool m_matUisUptodate;
Index m_maxIters;
typedef Matrix<Scalar,3,1> Vector3s;
Scalar computeNormOfT();
Index findSmallSubdiagEntry(Index iu);
void splitOffTwoRows(Index iu, bool computeU, const Scalar& exshift);
void computeShift(Index iu, Index iter, Scalar& exshift, Vector3s& shiftInfo);
void initFrancisQRStep(Index il, Index iu, const Vector3s& shiftInfo, Index& im, Vector3s& firstHouseholderVector);
void performFrancisQRStep(Index il, Index im, Index iu, bool computeU, const Vector3s& firstHouseholderVector, Scalar* workspace);
};
template<typename MatrixType>
template<typename InputType>
RealSchur<MatrixType>& RealSchur<MatrixType>::compute(const EigenBase<InputType>& matrix, bool computeU)
{
const Scalar considerAsZero = (std::numeric_limits<Scalar>::min)();
eigen_assert(matrix.cols() == matrix.rows());
Index maxIters = m_maxIters;
if (maxIters == -1)
maxIters = m_maxIterationsPerRow * matrix.rows();
Scalar scale = matrix.derived().cwiseAbs().maxCoeff();
if(scale<considerAsZero)
{
m_matT.setZero(matrix.rows(),matrix.cols());
if(computeU)
m_matU.setIdentity(matrix.rows(),matrix.cols());
m_info = Success;
m_isInitialized = true;
m_matUisUptodate = computeU;
return *this;
}
// Step 1. Reduce to Hessenberg form
m_hess.compute(matrix.derived()/scale);
// Step 2. Reduce to real Schur form
computeFromHessenberg(m_hess.matrixH(), m_hess.matrixQ(), computeU);
m_matT *= scale;
return *this;
}
template<typename MatrixType>
template<typename HessMatrixType, typename OrthMatrixType>
RealSchur<MatrixType>& RealSchur<MatrixType>::computeFromHessenberg(const HessMatrixType& matrixH, const OrthMatrixType& matrixQ, bool computeU)
{
using std::abs;
m_matT = matrixH;
if(computeU)
m_matU = matrixQ;
Index maxIters = m_maxIters;
if (maxIters == -1)
maxIters = m_maxIterationsPerRow * matrixH.rows();
m_workspaceVector.resize(m_matT.cols());
Scalar* workspace = &m_workspaceVector.coeffRef(0);
// The matrix m_matT is divided in three parts.
// Rows 0,...,il-1 are decoupled from the rest because m_matT(il,il-1) is zero.
// Rows il,...,iu is the part we are working on (the active window).
// Rows iu+1,...,end are already brought in triangular form.
Index iu = m_matT.cols() - 1;
Index iter = 0; // iteration count for current eigenvalue
Index totalIter = 0; // iteration count for whole matrix
Scalar exshift(0); // sum of exceptional shifts
Scalar norm = computeNormOfT();
if(norm!=Scalar(0))
{
while (iu >= 0)
{
Index il = findSmallSubdiagEntry(iu);
// Check for convergence
if (il == iu) // One root found
{
m_matT.coeffRef(iu,iu) = m_matT.coeff(iu,iu) + exshift;
if (iu > 0)
m_matT.coeffRef(iu, iu-1) = Scalar(0);
iu--;
iter = 0;
}
else if (il == iu-1) // Two roots found
{
splitOffTwoRows(iu, computeU, exshift);
iu -= 2;
iter = 0;
}
else // No convergence yet
{
// The firstHouseholderVector vector has to be initialized to something to get rid of a silly GCC warning (-O1 -Wall -DNDEBUG )
Vector3s firstHouseholderVector = Vector3s::Zero(), shiftInfo;
computeShift(iu, iter, exshift, shiftInfo);
iter = iter + 1;
totalIter = totalIter + 1;
if (totalIter > maxIters) break;
Index im;
initFrancisQRStep(il, iu, shiftInfo, im, firstHouseholderVector);
performFrancisQRStep(il, im, iu, computeU, firstHouseholderVector, workspace);
}
}
}
if(totalIter <= maxIters)
m_info = Success;
else
m_info = NoConvergence;
m_isInitialized = true;
m_matUisUptodate = computeU;
return *this;
}
/** \internal Computes and returns vector L1 norm of T */
template<typename MatrixType>
inline typename MatrixType::Scalar RealSchur<MatrixType>::computeNormOfT()
{
const Index size = m_matT.cols();
// FIXME to be efficient the following would requires a triangular reduxion code
// Scalar norm = m_matT.upper().cwiseAbs().sum()
// + m_matT.bottomLeftCorner(size-1,size-1).diagonal().cwiseAbs().sum();
Scalar norm(0);
for (Index j = 0; j < size; ++j)
norm += m_matT.col(j).segment(0, (std::min)(size,j+2)).cwiseAbs().sum();
return norm;
}
/** \internal Look for single small sub-diagonal element and returns its index */
template<typename MatrixType>
inline Index RealSchur<MatrixType>::findSmallSubdiagEntry(Index iu)
{
using std::abs;
Index res = iu;
while (res > 0)
{
Scalar s = abs(m_matT.coeff(res-1,res-1)) + abs(m_matT.coeff(res,res));
if (abs(m_matT.coeff(res,res-1)) <= NumTraits<Scalar>::epsilon() * s)
break;
res--;
}
return res;
}
/** \internal Update T given that rows iu-1 and iu decouple from the rest. */
template<typename MatrixType>
inline void RealSchur<MatrixType>::splitOffTwoRows(Index iu, bool computeU, const Scalar& exshift)
{
using std::sqrt;
using std::abs;
const Index size = m_matT.cols();
// The eigenvalues of the 2x2 matrix [a b; c d] are
// trace +/- sqrt(discr/4) where discr = tr^2 - 4*det, tr = a + d, det = ad - bc
Scalar p = Scalar(0.5) * (m_matT.coeff(iu-1,iu-1) - m_matT.coeff(iu,iu));
Scalar q = p * p + m_matT.coeff(iu,iu-1) * m_matT.coeff(iu-1,iu); // q = tr^2 / 4 - det = discr/4
m_matT.coeffRef(iu,iu) += exshift;
m_matT.coeffRef(iu-1,iu-1) += exshift;
if (q >= Scalar(0)) // Two real eigenvalues
{
Scalar z = sqrt(abs(q));
JacobiRotation<Scalar> rot;
if (p >= Scalar(0))
rot.makeGivens(p + z, m_matT.coeff(iu, iu-1));
else
rot.makeGivens(p - z, m_matT.coeff(iu, iu-1));
m_matT.rightCols(size-iu+1).applyOnTheLeft(iu-1, iu, rot.adjoint());
m_matT.topRows(iu+1).applyOnTheRight(iu-1, iu, rot);
m_matT.coeffRef(iu, iu-1) = Scalar(0);
if (computeU)
m_matU.applyOnTheRight(iu-1, iu, rot);
}
if (iu > 1)
m_matT.coeffRef(iu-1, iu-2) = Scalar(0);
}
/** \internal Form shift in shiftInfo, and update exshift if an exceptional shift is performed. */
template<typename MatrixType>
inline void RealSchur<MatrixType>::computeShift(Index iu, Index iter, Scalar& exshift, Vector3s& shiftInfo)
{
using std::sqrt;
using std::abs;
shiftInfo.coeffRef(0) = m_matT.coeff(iu,iu);
shiftInfo.coeffRef(1) = m_matT.coeff(iu-1,iu-1);
shiftInfo.coeffRef(2) = m_matT.coeff(iu,iu-1) * m_matT.coeff(iu-1,iu);
// Wilkinson's original ad hoc shift
if (iter == 10)
{
exshift += shiftInfo.coeff(0);
for (Index i = 0; i <= iu; ++i)
m_matT.coeffRef(i,i) -= shiftInfo.coeff(0);
Scalar s = abs(m_matT.coeff(iu,iu-1)) + abs(m_matT.coeff(iu-1,iu-2));
shiftInfo.coeffRef(0) = Scalar(0.75) * s;
shiftInfo.coeffRef(1) = Scalar(0.75) * s;
shiftInfo.coeffRef(2) = Scalar(-0.4375) * s * s;
}
// MATLAB's new ad hoc shift
if (iter == 30)
{
Scalar s = (shiftInfo.coeff(1) - shiftInfo.coeff(0)) / Scalar(2.0);
s = s * s + shiftInfo.coeff(2);
if (s > Scalar(0))
{
s = sqrt(s);
if (shiftInfo.coeff(1) < shiftInfo.coeff(0))
s = -s;
s = s + (shiftInfo.coeff(1) - shiftInfo.coeff(0)) / Scalar(2.0);
s = shiftInfo.coeff(0) - shiftInfo.coeff(2) / s;
exshift += s;
for (Index i = 0; i <= iu; ++i)
m_matT.coeffRef(i,i) -= s;
shiftInfo.setConstant(Scalar(0.964));
}
}
}
/** \internal Compute index im at which Francis QR step starts and the first Householder vector. */
template<typename MatrixType>
inline void RealSchur<MatrixType>::initFrancisQRStep(Index il, Index iu, const Vector3s& shiftInfo, Index& im, Vector3s& firstHouseholderVector)
{
using std::abs;
Vector3s& v = firstHouseholderVector; // alias to save typing
for (im = iu-2; im >= il; --im)
{
const Scalar Tmm = m_matT.coeff(im,im);
const Scalar r = shiftInfo.coeff(0) - Tmm;
const Scalar s = shiftInfo.coeff(1) - Tmm;
v.coeffRef(0) = (r * s - shiftInfo.coeff(2)) / m_matT.coeff(im+1,im) + m_matT.coeff(im,im+1);
v.coeffRef(1) = m_matT.coeff(im+1,im+1) - Tmm - r - s;
v.coeffRef(2) = m_matT.coeff(im+2,im+1);
if (im == il) {
break;
}
const Scalar lhs = m_matT.coeff(im,im-1) * (abs(v.coeff(1)) + abs(v.coeff(2)));
const Scalar rhs = v.coeff(0) * (abs(m_matT.coeff(im-1,im-1)) + abs(Tmm) + abs(m_matT.coeff(im+1,im+1)));
if (abs(lhs) < NumTraits<Scalar>::epsilon() * rhs)
break;
}
}
/** \internal Perform a Francis QR step involving rows il:iu and columns im:iu. */
template<typename MatrixType>
inline void RealSchur<MatrixType>::performFrancisQRStep(Index il, Index im, Index iu, bool computeU, const Vector3s& firstHouseholderVector, Scalar* workspace)
{
eigen_assert(im >= il);
eigen_assert(im <= iu-2);
const Index size = m_matT.cols();
for (Index k = im; k <= iu-2; ++k)
{
bool firstIteration = (k == im);
Vector3s v;
if (firstIteration)
v = firstHouseholderVector;
else
v = m_matT.template block<3,1>(k,k-1);
Scalar tau, beta;
Matrix<Scalar, 2, 1> ess;
v.makeHouseholder(ess, tau, beta);
if (beta != Scalar(0)) // if v is not zero
{
if (firstIteration && k > il)
m_matT.coeffRef(k,k-1) = -m_matT.coeff(k,k-1);
else if (!firstIteration)
m_matT.coeffRef(k,k-1) = beta;
// These Householder transformations form the O(n^3) part of the algorithm
m_matT.block(k, k, 3, size-k).applyHouseholderOnTheLeft(ess, tau, workspace);
m_matT.block(0, k, (std::min)(iu,k+3) + 1, 3).applyHouseholderOnTheRight(ess, tau, workspace);
if (computeU)
m_matU.block(0, k, size, 3).applyHouseholderOnTheRight(ess, tau, workspace);
}
}
Matrix<Scalar, 2, 1> v = m_matT.template block<2,1>(iu-1, iu-2);
Scalar tau, beta;
Matrix<Scalar, 1, 1> ess;
v.makeHouseholder(ess, tau, beta);
if (beta != Scalar(0)) // if v is not zero
{
m_matT.coeffRef(iu-1, iu-2) = beta;
m_matT.block(iu-1, iu-1, 2, size-iu+1).applyHouseholderOnTheLeft(ess, tau, workspace);
m_matT.block(0, iu-1, iu+1, 2).applyHouseholderOnTheRight(ess, tau, workspace);
if (computeU)
m_matU.block(0, iu-1, size, 2).applyHouseholderOnTheRight(ess, tau, workspace);
}
// clean up pollution due to round-off errors
for (Index i = im+2; i <= iu; ++i)
{
m_matT.coeffRef(i,i-2) = Scalar(0);
if (i > im+2)
m_matT.coeffRef(i,i-3) = Scalar(0);
}
}
} // end namespace Eigen
#endif // EIGEN_REAL_SCHUR_H

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/*
Copyright (c) 2011, Intel Corporation. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its contributors may
be used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
********************************************************************************
* Content : Eigen bindings to LAPACKe
* Real Schur needed to real unsymmetrical eigenvalues/eigenvectors.
********************************************************************************
*/
#ifndef EIGEN_REAL_SCHUR_LAPACKE_H
#define EIGEN_REAL_SCHUR_LAPACKE_H
namespace Eigen {
/** \internal Specialization for the data types supported by LAPACKe */
#define EIGEN_LAPACKE_SCHUR_REAL(EIGTYPE, LAPACKE_TYPE, LAPACKE_PREFIX, LAPACKE_PREFIX_U, EIGCOLROW, LAPACKE_COLROW) \
template<> template<typename InputType> inline \
RealSchur<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >& \
RealSchur<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >::compute(const EigenBase<InputType>& matrix, bool computeU) \
{ \
eigen_assert(matrix.cols() == matrix.rows()); \
\
lapack_int n = internal::convert_index<lapack_int>(matrix.cols()), sdim, info; \
lapack_int matrix_order = LAPACKE_COLROW; \
char jobvs, sort='N'; \
LAPACK_##LAPACKE_PREFIX_U##_SELECT2 select = 0; \
jobvs = (computeU) ? 'V' : 'N'; \
m_matU.resize(n, n); \
lapack_int ldvs = internal::convert_index<lapack_int>(m_matU.outerStride()); \
m_matT = matrix; \
lapack_int lda = internal::convert_index<lapack_int>(m_matT.outerStride()); \
Matrix<EIGTYPE, Dynamic, Dynamic> wr, wi; \
wr.resize(n, 1); wi.resize(n, 1); \
info = LAPACKE_##LAPACKE_PREFIX##gees( matrix_order, jobvs, sort, select, n, (LAPACKE_TYPE*)m_matT.data(), lda, &sdim, (LAPACKE_TYPE*)wr.data(), (LAPACKE_TYPE*)wi.data(), (LAPACKE_TYPE*)m_matU.data(), ldvs ); \
if(info == 0) \
m_info = Success; \
else \
m_info = NoConvergence; \
\
m_isInitialized = true; \
m_matUisUptodate = computeU; \
return *this; \
\
}
EIGEN_LAPACKE_SCHUR_REAL(double, double, d, D, ColMajor, LAPACK_COL_MAJOR)
EIGEN_LAPACKE_SCHUR_REAL(float, float, s, S, ColMajor, LAPACK_COL_MAJOR)
EIGEN_LAPACKE_SCHUR_REAL(double, double, d, D, RowMajor, LAPACK_ROW_MAJOR)
EIGEN_LAPACKE_SCHUR_REAL(float, float, s, S, RowMajor, LAPACK_ROW_MAJOR)
} // end namespace Eigen
#endif // EIGEN_REAL_SCHUR_LAPACKE_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_SELFADJOINTEIGENSOLVER_H
#define EIGEN_SELFADJOINTEIGENSOLVER_H
#include "./Tridiagonalization.h"
namespace Eigen {
template<typename _MatrixType>
class GeneralizedSelfAdjointEigenSolver;
namespace internal {
template<typename SolverType,int Size,bool IsComplex> struct direct_selfadjoint_eigenvalues;
template<typename MatrixType, typename DiagType, typename SubDiagType>
ComputationInfo computeFromTridiagonal_impl(DiagType& diag, SubDiagType& subdiag, const Index maxIterations, bool computeEigenvectors, MatrixType& eivec);
}
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class SelfAdjointEigenSolver
*
* \brief Computes eigenvalues and eigenvectors of selfadjoint matrices
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* eigendecomposition; this is expected to be an instantiation of the Matrix
* class template.
*
* A matrix \f$ A \f$ is selfadjoint if it equals its adjoint. For real
* matrices, this means that the matrix is symmetric: it equals its
* transpose. This class computes the eigenvalues and eigenvectors of a
* selfadjoint matrix. These are the scalars \f$ \lambda \f$ and vectors
* \f$ v \f$ such that \f$ Av = \lambda v \f$. The eigenvalues of a
* selfadjoint matrix are always real. If \f$ D \f$ is a diagonal matrix with
* the eigenvalues on the diagonal, and \f$ V \f$ is a matrix with the
* eigenvectors as its columns, then \f$ A = V D V^{-1} \f$ (for selfadjoint
* matrices, the matrix \f$ V \f$ is always invertible). This is called the
* eigendecomposition.
*
* The algorithm exploits the fact that the matrix is selfadjoint, making it
* faster and more accurate than the general purpose eigenvalue algorithms
* implemented in EigenSolver and ComplexEigenSolver.
*
* Only the \b lower \b triangular \b part of the input matrix is referenced.
*
* Call the function compute() to compute the eigenvalues and eigenvectors of
* a given matrix. Alternatively, you can use the
* SelfAdjointEigenSolver(const MatrixType&, int) constructor which computes
* the eigenvalues and eigenvectors at construction time. Once the eigenvalue
* and eigenvectors are computed, they can be retrieved with the eigenvalues()
* and eigenvectors() functions.
*
* The documentation for SelfAdjointEigenSolver(const MatrixType&, int)
* contains an example of the typical use of this class.
*
* To solve the \em generalized eigenvalue problem \f$ Av = \lambda Bv \f$ and
* the likes, see the class GeneralizedSelfAdjointEigenSolver.
*
* \sa MatrixBase::eigenvalues(), class EigenSolver, class ComplexEigenSolver
*/
template<typename _MatrixType> class SelfAdjointEigenSolver
{
public:
typedef _MatrixType MatrixType;
enum {
Size = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
Options = MatrixType::Options,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
};
/** \brief Scalar type for matrices of type \p _MatrixType. */
typedef typename MatrixType::Scalar Scalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
typedef Matrix<Scalar,Size,Size,ColMajor,MaxColsAtCompileTime,MaxColsAtCompileTime> EigenvectorsType;
/** \brief Real scalar type for \p _MatrixType.
*
* This is just \c Scalar if #Scalar is real (e.g., \c float or
* \c double), and the type of the real part of \c Scalar if #Scalar is
* complex.
*/
typedef typename NumTraits<Scalar>::Real RealScalar;
friend struct internal::direct_selfadjoint_eigenvalues<SelfAdjointEigenSolver,Size,NumTraits<Scalar>::IsComplex>;
/** \brief Type for vector of eigenvalues as returned by eigenvalues().
*
* This is a column vector with entries of type #RealScalar.
* The length of the vector is the size of \p _MatrixType.
*/
typedef typename internal::plain_col_type<MatrixType, RealScalar>::type RealVectorType;
typedef Tridiagonalization<MatrixType> TridiagonalizationType;
typedef typename TridiagonalizationType::SubDiagonalType SubDiagonalType;
/** \brief Default constructor for fixed-size matrices.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). This constructor
* can only be used if \p _MatrixType is a fixed-size matrix; use
* SelfAdjointEigenSolver(Index) for dynamic-size matrices.
*
* Example: \include SelfAdjointEigenSolver_SelfAdjointEigenSolver.cpp
* Output: \verbinclude SelfAdjointEigenSolver_SelfAdjointEigenSolver.out
*/
EIGEN_DEVICE_FUNC
SelfAdjointEigenSolver()
: m_eivec(),
m_eivalues(),
m_subdiag(),
m_isInitialized(false)
{ }
/** \brief Constructor, pre-allocates memory for dynamic-size matrices.
*
* \param [in] size Positive integer, size of the matrix whose
* eigenvalues and eigenvectors will be computed.
*
* This constructor is useful for dynamic-size matrices, when the user
* intends to perform decompositions via compute(). The \p size
* parameter is only used as a hint. It is not an error to give a wrong
* \p size, but it may impair performance.
*
* \sa compute() for an example
*/
EIGEN_DEVICE_FUNC
explicit SelfAdjointEigenSolver(Index size)
: m_eivec(size, size),
m_eivalues(size),
m_subdiag(size > 1 ? size - 1 : 1),
m_isInitialized(false)
{}
/** \brief Constructor; computes eigendecomposition of given matrix.
*
* \param[in] matrix Selfadjoint matrix whose eigendecomposition is to
* be computed. Only the lower triangular part of the matrix is referenced.
* \param[in] options Can be #ComputeEigenvectors (default) or #EigenvaluesOnly.
*
* This constructor calls compute(const MatrixType&, int) to compute the
* eigenvalues of the matrix \p matrix. The eigenvectors are computed if
* \p options equals #ComputeEigenvectors.
*
* Example: \include SelfAdjointEigenSolver_SelfAdjointEigenSolver_MatrixType.cpp
* Output: \verbinclude SelfAdjointEigenSolver_SelfAdjointEigenSolver_MatrixType.out
*
* \sa compute(const MatrixType&, int)
*/
template<typename InputType>
EIGEN_DEVICE_FUNC
explicit SelfAdjointEigenSolver(const EigenBase<InputType>& matrix, int options = ComputeEigenvectors)
: m_eivec(matrix.rows(), matrix.cols()),
m_eivalues(matrix.cols()),
m_subdiag(matrix.rows() > 1 ? matrix.rows() - 1 : 1),
m_isInitialized(false)
{
compute(matrix.derived(), options);
}
/** \brief Computes eigendecomposition of given matrix.
*
* \param[in] matrix Selfadjoint matrix whose eigendecomposition is to
* be computed. Only the lower triangular part of the matrix is referenced.
* \param[in] options Can be #ComputeEigenvectors (default) or #EigenvaluesOnly.
* \returns Reference to \c *this
*
* This function computes the eigenvalues of \p matrix. The eigenvalues()
* function can be used to retrieve them. If \p options equals #ComputeEigenvectors,
* then the eigenvectors are also computed and can be retrieved by
* calling eigenvectors().
*
* This implementation uses a symmetric QR algorithm. The matrix is first
* reduced to tridiagonal form using the Tridiagonalization class. The
* tridiagonal matrix is then brought to diagonal form with implicit
* symmetric QR steps with Wilkinson shift. Details can be found in
* Section 8.3 of Golub \& Van Loan, <i>%Matrix Computations</i>.
*
* The cost of the computation is about \f$ 9n^3 \f$ if the eigenvectors
* are required and \f$ 4n^3/3 \f$ if they are not required.
*
* This method reuses the memory in the SelfAdjointEigenSolver object that
* was allocated when the object was constructed, if the size of the
* matrix does not change.
*
* Example: \include SelfAdjointEigenSolver_compute_MatrixType.cpp
* Output: \verbinclude SelfAdjointEigenSolver_compute_MatrixType.out
*
* \sa SelfAdjointEigenSolver(const MatrixType&, int)
*/
template<typename InputType>
EIGEN_DEVICE_FUNC
SelfAdjointEigenSolver& compute(const EigenBase<InputType>& matrix, int options = ComputeEigenvectors);
/** \brief Computes eigendecomposition of given matrix using a closed-form algorithm
*
* This is a variant of compute(const MatrixType&, int options) which
* directly solves the underlying polynomial equation.
*
* Currently only 2x2 and 3x3 matrices for which the sizes are known at compile time are supported (e.g., Matrix3d).
*
* This method is usually significantly faster than the QR iterative algorithm
* but it might also be less accurate. It is also worth noting that
* for 3x3 matrices it involves trigonometric operations which are
* not necessarily available for all scalar types.
*
* For the 3x3 case, we observed the following worst case relative error regarding the eigenvalues:
* - double: 1e-8
* - float: 1e-3
*
* \sa compute(const MatrixType&, int options)
*/
EIGEN_DEVICE_FUNC
SelfAdjointEigenSolver& computeDirect(const MatrixType& matrix, int options = ComputeEigenvectors);
/**
*\brief Computes the eigen decomposition from a tridiagonal symmetric matrix
*
* \param[in] diag The vector containing the diagonal of the matrix.
* \param[in] subdiag The subdiagonal of the matrix.
* \param[in] options Can be #ComputeEigenvectors (default) or #EigenvaluesOnly.
* \returns Reference to \c *this
*
* This function assumes that the matrix has been reduced to tridiagonal form.
*
* \sa compute(const MatrixType&, int) for more information
*/
SelfAdjointEigenSolver& computeFromTridiagonal(const RealVectorType& diag, const SubDiagonalType& subdiag , int options=ComputeEigenvectors);
/** \brief Returns the eigenvectors of given matrix.
*
* \returns A const reference to the matrix whose columns are the eigenvectors.
*
* \pre The eigenvectors have been computed before.
*
* Column \f$ k \f$ of the returned matrix is an eigenvector corresponding
* to eigenvalue number \f$ k \f$ as returned by eigenvalues(). The
* eigenvectors are normalized to have (Euclidean) norm equal to one. If
* this object was used to solve the eigenproblem for the selfadjoint
* matrix \f$ A \f$, then the matrix returned by this function is the
* matrix \f$ V \f$ in the eigendecomposition \f$ A = V D V^{-1} \f$.
*
* Example: \include SelfAdjointEigenSolver_eigenvectors.cpp
* Output: \verbinclude SelfAdjointEigenSolver_eigenvectors.out
*
* \sa eigenvalues()
*/
EIGEN_DEVICE_FUNC
const EigenvectorsType& eigenvectors() const
{
eigen_assert(m_isInitialized && "SelfAdjointEigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
return m_eivec;
}
/** \brief Returns the eigenvalues of given matrix.
*
* \returns A const reference to the column vector containing the eigenvalues.
*
* \pre The eigenvalues have been computed before.
*
* The eigenvalues are repeated according to their algebraic multiplicity,
* so there are as many eigenvalues as rows in the matrix. The eigenvalues
* are sorted in increasing order.
*
* Example: \include SelfAdjointEigenSolver_eigenvalues.cpp
* Output: \verbinclude SelfAdjointEigenSolver_eigenvalues.out
*
* \sa eigenvectors(), MatrixBase::eigenvalues()
*/
EIGEN_DEVICE_FUNC
const RealVectorType& eigenvalues() const
{
eigen_assert(m_isInitialized && "SelfAdjointEigenSolver is not initialized.");
return m_eivalues;
}
/** \brief Computes the positive-definite square root of the matrix.
*
* \returns the positive-definite square root of the matrix
*
* \pre The eigenvalues and eigenvectors of a positive-definite matrix
* have been computed before.
*
* The square root of a positive-definite matrix \f$ A \f$ is the
* positive-definite matrix whose square equals \f$ A \f$. This function
* uses the eigendecomposition \f$ A = V D V^{-1} \f$ to compute the
* square root as \f$ A^{1/2} = V D^{1/2} V^{-1} \f$.
*
* Example: \include SelfAdjointEigenSolver_operatorSqrt.cpp
* Output: \verbinclude SelfAdjointEigenSolver_operatorSqrt.out
*
* \sa operatorInverseSqrt(), <a href="unsupported/group__MatrixFunctions__Module.html">MatrixFunctions Module</a>
*/
EIGEN_DEVICE_FUNC
MatrixType operatorSqrt() const
{
eigen_assert(m_isInitialized && "SelfAdjointEigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
return m_eivec * m_eivalues.cwiseSqrt().asDiagonal() * m_eivec.adjoint();
}
/** \brief Computes the inverse square root of the matrix.
*
* \returns the inverse positive-definite square root of the matrix
*
* \pre The eigenvalues and eigenvectors of a positive-definite matrix
* have been computed before.
*
* This function uses the eigendecomposition \f$ A = V D V^{-1} \f$ to
* compute the inverse square root as \f$ V D^{-1/2} V^{-1} \f$. This is
* cheaper than first computing the square root with operatorSqrt() and
* then its inverse with MatrixBase::inverse().
*
* Example: \include SelfAdjointEigenSolver_operatorInverseSqrt.cpp
* Output: \verbinclude SelfAdjointEigenSolver_operatorInverseSqrt.out
*
* \sa operatorSqrt(), MatrixBase::inverse(), <a href="unsupported/group__MatrixFunctions__Module.html">MatrixFunctions Module</a>
*/
EIGEN_DEVICE_FUNC
MatrixType operatorInverseSqrt() const
{
eigen_assert(m_isInitialized && "SelfAdjointEigenSolver is not initialized.");
eigen_assert(m_eigenvectorsOk && "The eigenvectors have not been computed together with the eigenvalues.");
return m_eivec * m_eivalues.cwiseInverse().cwiseSqrt().asDiagonal() * m_eivec.adjoint();
}
/** \brief Reports whether previous computation was successful.
*
* \returns \c Success if computation was succesful, \c NoConvergence otherwise.
*/
EIGEN_DEVICE_FUNC
ComputationInfo info() const
{
eigen_assert(m_isInitialized && "SelfAdjointEigenSolver is not initialized.");
return m_info;
}
/** \brief Maximum number of iterations.
*
* The algorithm terminates if it does not converge within m_maxIterations * n iterations, where n
* denotes the size of the matrix. This value is currently set to 30 (copied from LAPACK).
*/
static const int m_maxIterations = 30;
protected:
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
}
EigenvectorsType m_eivec;
RealVectorType m_eivalues;
typename TridiagonalizationType::SubDiagonalType m_subdiag;
ComputationInfo m_info;
bool m_isInitialized;
bool m_eigenvectorsOk;
};
namespace internal {
/** \internal
*
* \eigenvalues_module \ingroup Eigenvalues_Module
*
* Performs a QR step on a tridiagonal symmetric matrix represented as a
* pair of two vectors \a diag and \a subdiag.
*
* \param diag the diagonal part of the input selfadjoint tridiagonal matrix
* \param subdiag the sub-diagonal part of the input selfadjoint tridiagonal matrix
* \param start starting index of the submatrix to work on
* \param end last+1 index of the submatrix to work on
* \param matrixQ pointer to the column-major matrix holding the eigenvectors, can be 0
* \param n size of the input matrix
*
* For compilation efficiency reasons, this procedure does not use eigen expression
* for its arguments.
*
* Implemented from Golub's "Matrix Computations", algorithm 8.3.2:
* "implicit symmetric QR step with Wilkinson shift"
*/
template<int StorageOrder,typename RealScalar, typename Scalar, typename Index>
EIGEN_DEVICE_FUNC
static void tridiagonal_qr_step(RealScalar* diag, RealScalar* subdiag, Index start, Index end, Scalar* matrixQ, Index n);
}
template<typename MatrixType>
template<typename InputType>
EIGEN_DEVICE_FUNC
SelfAdjointEigenSolver<MatrixType>& SelfAdjointEigenSolver<MatrixType>
::compute(const EigenBase<InputType>& a_matrix, int options)
{
check_template_parameters();
const InputType &matrix(a_matrix.derived());
using std::abs;
eigen_assert(matrix.cols() == matrix.rows());
eigen_assert((options&~(EigVecMask|GenEigMask))==0
&& (options&EigVecMask)!=EigVecMask
&& "invalid option parameter");
bool computeEigenvectors = (options&ComputeEigenvectors)==ComputeEigenvectors;
Index n = matrix.cols();
m_eivalues.resize(n,1);
if(n==1)
{
m_eivec = matrix;
m_eivalues.coeffRef(0,0) = numext::real(m_eivec.coeff(0,0));
if(computeEigenvectors)
m_eivec.setOnes(n,n);
m_info = Success;
m_isInitialized = true;
m_eigenvectorsOk = computeEigenvectors;
return *this;
}
// declare some aliases
RealVectorType& diag = m_eivalues;
EigenvectorsType& mat = m_eivec;
// map the matrix coefficients to [-1:1] to avoid over- and underflow.
mat = matrix.template triangularView<Lower>();
RealScalar scale = mat.cwiseAbs().maxCoeff();
if(scale==RealScalar(0)) scale = RealScalar(1);
mat.template triangularView<Lower>() /= scale;
m_subdiag.resize(n-1);
internal::tridiagonalization_inplace(mat, diag, m_subdiag, computeEigenvectors);
m_info = internal::computeFromTridiagonal_impl(diag, m_subdiag, m_maxIterations, computeEigenvectors, m_eivec);
// scale back the eigen values
m_eivalues *= scale;
m_isInitialized = true;
m_eigenvectorsOk = computeEigenvectors;
return *this;
}
template<typename MatrixType>
SelfAdjointEigenSolver<MatrixType>& SelfAdjointEigenSolver<MatrixType>
::computeFromTridiagonal(const RealVectorType& diag, const SubDiagonalType& subdiag , int options)
{
//TODO : Add an option to scale the values beforehand
bool computeEigenvectors = (options&ComputeEigenvectors)==ComputeEigenvectors;
m_eivalues = diag;
m_subdiag = subdiag;
if (computeEigenvectors)
{
m_eivec.setIdentity(diag.size(), diag.size());
}
m_info = internal::computeFromTridiagonal_impl(m_eivalues, m_subdiag, m_maxIterations, computeEigenvectors, m_eivec);
m_isInitialized = true;
m_eigenvectorsOk = computeEigenvectors;
return *this;
}
namespace internal {
/**
* \internal
* \brief Compute the eigendecomposition from a tridiagonal matrix
*
* \param[in,out] diag : On input, the diagonal of the matrix, on output the eigenvalues
* \param[in,out] subdiag : The subdiagonal part of the matrix (entries are modified during the decomposition)
* \param[in] maxIterations : the maximum number of iterations
* \param[in] computeEigenvectors : whether the eigenvectors have to be computed or not
* \param[out] eivec : The matrix to store the eigenvectors if computeEigenvectors==true. Must be allocated on input.
* \returns \c Success or \c NoConvergence
*/
template<typename MatrixType, typename DiagType, typename SubDiagType>
ComputationInfo computeFromTridiagonal_impl(DiagType& diag, SubDiagType& subdiag, const Index maxIterations, bool computeEigenvectors, MatrixType& eivec)
{
using std::abs;
ComputationInfo info;
typedef typename MatrixType::Scalar Scalar;
Index n = diag.size();
Index end = n-1;
Index start = 0;
Index iter = 0; // total number of iterations
typedef typename DiagType::RealScalar RealScalar;
const RealScalar considerAsZero = (std::numeric_limits<RealScalar>::min)();
const RealScalar precision = RealScalar(2)*NumTraits<RealScalar>::epsilon();
while (end>0)
{
for (Index i = start; i<end; ++i)
if (internal::isMuchSmallerThan(abs(subdiag[i]),(abs(diag[i])+abs(diag[i+1])),precision) || abs(subdiag[i]) <= considerAsZero)
subdiag[i] = 0;
// find the largest unreduced block
while (end>0 && subdiag[end-1]==RealScalar(0))
{
end--;
}
if (end<=0)
break;
// if we spent too many iterations, we give up
iter++;
if(iter > maxIterations * n) break;
start = end - 1;
while (start>0 && subdiag[start-1]!=0)
start--;
internal::tridiagonal_qr_step<MatrixType::Flags&RowMajorBit ? RowMajor : ColMajor>(diag.data(), subdiag.data(), start, end, computeEigenvectors ? eivec.data() : (Scalar*)0, n);
}
if (iter <= maxIterations * n)
info = Success;
else
info = NoConvergence;
// Sort eigenvalues and corresponding vectors.
// TODO make the sort optional ?
// TODO use a better sort algorithm !!
if (info == Success)
{
for (Index i = 0; i < n-1; ++i)
{
Index k;
diag.segment(i,n-i).minCoeff(&k);
if (k > 0)
{
std::swap(diag[i], diag[k+i]);
if(computeEigenvectors)
eivec.col(i).swap(eivec.col(k+i));
}
}
}
return info;
}
template<typename SolverType,int Size,bool IsComplex> struct direct_selfadjoint_eigenvalues
{
EIGEN_DEVICE_FUNC
static inline void run(SolverType& eig, const typename SolverType::MatrixType& A, int options)
{ eig.compute(A,options); }
};
template<typename SolverType> struct direct_selfadjoint_eigenvalues<SolverType,3,false>
{
typedef typename SolverType::MatrixType MatrixType;
typedef typename SolverType::RealVectorType VectorType;
typedef typename SolverType::Scalar Scalar;
typedef typename SolverType::EigenvectorsType EigenvectorsType;
/** \internal
* Computes the roots of the characteristic polynomial of \a m.
* For numerical stability m.trace() should be near zero and to avoid over- or underflow m should be normalized.
*/
EIGEN_DEVICE_FUNC
static inline void computeRoots(const MatrixType& m, VectorType& roots)
{
EIGEN_USING_STD_MATH(sqrt)
EIGEN_USING_STD_MATH(atan2)
EIGEN_USING_STD_MATH(cos)
EIGEN_USING_STD_MATH(sin)
const Scalar s_inv3 = Scalar(1)/Scalar(3);
const Scalar s_sqrt3 = sqrt(Scalar(3));
// The characteristic equation is x^3 - c2*x^2 + c1*x - c0 = 0. The
// eigenvalues are the roots to this equation, all guaranteed to be
// real-valued, because the matrix is symmetric.
Scalar c0 = m(0,0)*m(1,1)*m(2,2) + Scalar(2)*m(1,0)*m(2,0)*m(2,1) - m(0,0)*m(2,1)*m(2,1) - m(1,1)*m(2,0)*m(2,0) - m(2,2)*m(1,0)*m(1,0);
Scalar c1 = m(0,0)*m(1,1) - m(1,0)*m(1,0) + m(0,0)*m(2,2) - m(2,0)*m(2,0) + m(1,1)*m(2,2) - m(2,1)*m(2,1);
Scalar c2 = m(0,0) + m(1,1) + m(2,2);
// Construct the parameters used in classifying the roots of the equation
// and in solving the equation for the roots in closed form.
Scalar c2_over_3 = c2*s_inv3;
Scalar a_over_3 = (c2*c2_over_3 - c1)*s_inv3;
a_over_3 = numext::maxi(a_over_3, Scalar(0));
Scalar half_b = Scalar(0.5)*(c0 + c2_over_3*(Scalar(2)*c2_over_3*c2_over_3 - c1));
Scalar q = a_over_3*a_over_3*a_over_3 - half_b*half_b;
q = numext::maxi(q, Scalar(0));
// Compute the eigenvalues by solving for the roots of the polynomial.
Scalar rho = sqrt(a_over_3);
Scalar theta = atan2(sqrt(q),half_b)*s_inv3; // since sqrt(q) > 0, atan2 is in [0, pi] and theta is in [0, pi/3]
Scalar cos_theta = cos(theta);
Scalar sin_theta = sin(theta);
// roots are already sorted, since cos is monotonically decreasing on [0, pi]
roots(0) = c2_over_3 - rho*(cos_theta + s_sqrt3*sin_theta); // == 2*rho*cos(theta+2pi/3)
roots(1) = c2_over_3 - rho*(cos_theta - s_sqrt3*sin_theta); // == 2*rho*cos(theta+ pi/3)
roots(2) = c2_over_3 + Scalar(2)*rho*cos_theta;
}
EIGEN_DEVICE_FUNC
static inline bool extract_kernel(MatrixType& mat, Ref<VectorType> res, Ref<VectorType> representative)
{
using std::abs;
Index i0;
// Find non-zero column i0 (by construction, there must exist a non zero coefficient on the diagonal):
mat.diagonal().cwiseAbs().maxCoeff(&i0);
// mat.col(i0) is a good candidate for an orthogonal vector to the current eigenvector,
// so let's save it:
representative = mat.col(i0);
Scalar n0, n1;
VectorType c0, c1;
n0 = (c0 = representative.cross(mat.col((i0+1)%3))).squaredNorm();
n1 = (c1 = representative.cross(mat.col((i0+2)%3))).squaredNorm();
if(n0>n1) res = c0/std::sqrt(n0);
else res = c1/std::sqrt(n1);
return true;
}
EIGEN_DEVICE_FUNC
static inline void run(SolverType& solver, const MatrixType& mat, int options)
{
eigen_assert(mat.cols() == 3 && mat.cols() == mat.rows());
eigen_assert((options&~(EigVecMask|GenEigMask))==0
&& (options&EigVecMask)!=EigVecMask
&& "invalid option parameter");
bool computeEigenvectors = (options&ComputeEigenvectors)==ComputeEigenvectors;
EigenvectorsType& eivecs = solver.m_eivec;
VectorType& eivals = solver.m_eivalues;
// Shift the matrix to the mean eigenvalue and map the matrix coefficients to [-1:1] to avoid over- and underflow.
Scalar shift = mat.trace() / Scalar(3);
// TODO Avoid this copy. Currently it is necessary to suppress bogus values when determining maxCoeff and for computing the eigenvectors later
MatrixType scaledMat = mat.template selfadjointView<Lower>();
scaledMat.diagonal().array() -= shift;
Scalar scale = scaledMat.cwiseAbs().maxCoeff();
if(scale > 0) scaledMat /= scale; // TODO for scale==0 we could save the remaining operations
// compute the eigenvalues
computeRoots(scaledMat,eivals);
// compute the eigenvectors
if(computeEigenvectors)
{
if((eivals(2)-eivals(0))<=Eigen::NumTraits<Scalar>::epsilon())
{
// All three eigenvalues are numerically the same
eivecs.setIdentity();
}
else
{
MatrixType tmp;
tmp = scaledMat;
// Compute the eigenvector of the most distinct eigenvalue
Scalar d0 = eivals(2) - eivals(1);
Scalar d1 = eivals(1) - eivals(0);
Index k(0), l(2);
if(d0 > d1)
{
numext::swap(k,l);
d0 = d1;
}
// Compute the eigenvector of index k
{
tmp.diagonal().array () -= eivals(k);
// By construction, 'tmp' is of rank 2, and its kernel corresponds to the respective eigenvector.
extract_kernel(tmp, eivecs.col(k), eivecs.col(l));
}
// Compute eigenvector of index l
if(d0<=2*Eigen::NumTraits<Scalar>::epsilon()*d1)
{
// If d0 is too small, then the two other eigenvalues are numerically the same,
// and thus we only have to ortho-normalize the near orthogonal vector we saved above.
eivecs.col(l) -= eivecs.col(k).dot(eivecs.col(l))*eivecs.col(l);
eivecs.col(l).normalize();
}
else
{
tmp = scaledMat;
tmp.diagonal().array () -= eivals(l);
VectorType dummy;
extract_kernel(tmp, eivecs.col(l), dummy);
}
// Compute last eigenvector from the other two
eivecs.col(1) = eivecs.col(2).cross(eivecs.col(0)).normalized();
}
}
// Rescale back to the original size.
eivals *= scale;
eivals.array() += shift;
solver.m_info = Success;
solver.m_isInitialized = true;
solver.m_eigenvectorsOk = computeEigenvectors;
}
};
// 2x2 direct eigenvalues decomposition, code from Hauke Heibel
template<typename SolverType>
struct direct_selfadjoint_eigenvalues<SolverType,2,false>
{
typedef typename SolverType::MatrixType MatrixType;
typedef typename SolverType::RealVectorType VectorType;
typedef typename SolverType::Scalar Scalar;
typedef typename SolverType::EigenvectorsType EigenvectorsType;
EIGEN_DEVICE_FUNC
static inline void computeRoots(const MatrixType& m, VectorType& roots)
{
using std::sqrt;
const Scalar t0 = Scalar(0.5) * sqrt( numext::abs2(m(0,0)-m(1,1)) + Scalar(4)*numext::abs2(m(1,0)));
const Scalar t1 = Scalar(0.5) * (m(0,0) + m(1,1));
roots(0) = t1 - t0;
roots(1) = t1 + t0;
}
EIGEN_DEVICE_FUNC
static inline void run(SolverType& solver, const MatrixType& mat, int options)
{
EIGEN_USING_STD_MATH(sqrt);
EIGEN_USING_STD_MATH(abs);
eigen_assert(mat.cols() == 2 && mat.cols() == mat.rows());
eigen_assert((options&~(EigVecMask|GenEigMask))==0
&& (options&EigVecMask)!=EigVecMask
&& "invalid option parameter");
bool computeEigenvectors = (options&ComputeEigenvectors)==ComputeEigenvectors;
EigenvectorsType& eivecs = solver.m_eivec;
VectorType& eivals = solver.m_eivalues;
// Shift the matrix to the mean eigenvalue and map the matrix coefficients to [-1:1] to avoid over- and underflow.
Scalar shift = mat.trace() / Scalar(2);
MatrixType scaledMat = mat;
scaledMat.coeffRef(0,1) = mat.coeff(1,0);
scaledMat.diagonal().array() -= shift;
Scalar scale = scaledMat.cwiseAbs().maxCoeff();
if(scale > Scalar(0))
scaledMat /= scale;
// Compute the eigenvalues
computeRoots(scaledMat,eivals);
// compute the eigen vectors
if(computeEigenvectors)
{
if((eivals(1)-eivals(0))<=abs(eivals(1))*Eigen::NumTraits<Scalar>::epsilon())
{
eivecs.setIdentity();
}
else
{
scaledMat.diagonal().array () -= eivals(1);
Scalar a2 = numext::abs2(scaledMat(0,0));
Scalar c2 = numext::abs2(scaledMat(1,1));
Scalar b2 = numext::abs2(scaledMat(1,0));
if(a2>c2)
{
eivecs.col(1) << -scaledMat(1,0), scaledMat(0,0);
eivecs.col(1) /= sqrt(a2+b2);
}
else
{
eivecs.col(1) << -scaledMat(1,1), scaledMat(1,0);
eivecs.col(1) /= sqrt(c2+b2);
}
eivecs.col(0) << eivecs.col(1).unitOrthogonal();
}
}
// Rescale back to the original size.
eivals *= scale;
eivals.array() += shift;
solver.m_info = Success;
solver.m_isInitialized = true;
solver.m_eigenvectorsOk = computeEigenvectors;
}
};
}
template<typename MatrixType>
EIGEN_DEVICE_FUNC
SelfAdjointEigenSolver<MatrixType>& SelfAdjointEigenSolver<MatrixType>
::computeDirect(const MatrixType& matrix, int options)
{
internal::direct_selfadjoint_eigenvalues<SelfAdjointEigenSolver,Size,NumTraits<Scalar>::IsComplex>::run(*this,matrix,options);
return *this;
}
namespace internal {
template<int StorageOrder,typename RealScalar, typename Scalar, typename Index>
EIGEN_DEVICE_FUNC
static void tridiagonal_qr_step(RealScalar* diag, RealScalar* subdiag, Index start, Index end, Scalar* matrixQ, Index n)
{
using std::abs;
RealScalar td = (diag[end-1] - diag[end])*RealScalar(0.5);
RealScalar e = subdiag[end-1];
// Note that thanks to scaling, e^2 or td^2 cannot overflow, however they can still
// underflow thus leading to inf/NaN values when using the following commented code:
// RealScalar e2 = numext::abs2(subdiag[end-1]);
// RealScalar mu = diag[end] - e2 / (td + (td>0 ? 1 : -1) * sqrt(td*td + e2));
// This explain the following, somewhat more complicated, version:
RealScalar mu = diag[end];
if(td==RealScalar(0))
mu -= abs(e);
else
{
RealScalar e2 = numext::abs2(subdiag[end-1]);
RealScalar h = numext::hypot(td,e);
if(e2==RealScalar(0)) mu -= (e / (td + (td>RealScalar(0) ? RealScalar(1) : RealScalar(-1)))) * (e / h);
else mu -= e2 / (td + (td>RealScalar(0) ? h : -h));
}
RealScalar x = diag[start] - mu;
RealScalar z = subdiag[start];
for (Index k = start; k < end; ++k)
{
JacobiRotation<RealScalar> rot;
rot.makeGivens(x, z);
// do T = G' T G
RealScalar sdk = rot.s() * diag[k] + rot.c() * subdiag[k];
RealScalar dkp1 = rot.s() * subdiag[k] + rot.c() * diag[k+1];
diag[k] = rot.c() * (rot.c() * diag[k] - rot.s() * subdiag[k]) - rot.s() * (rot.c() * subdiag[k] - rot.s() * diag[k+1]);
diag[k+1] = rot.s() * sdk + rot.c() * dkp1;
subdiag[k] = rot.c() * sdk - rot.s() * dkp1;
if (k > start)
subdiag[k - 1] = rot.c() * subdiag[k-1] - rot.s() * z;
x = subdiag[k];
if (k < end - 1)
{
z = -rot.s() * subdiag[k+1];
subdiag[k + 1] = rot.c() * subdiag[k+1];
}
// apply the givens rotation to the unit matrix Q = Q * G
if (matrixQ)
{
// FIXME if StorageOrder == RowMajor this operation is not very efficient
Map<Matrix<Scalar,Dynamic,Dynamic,StorageOrder> > q(matrixQ,n,n);
q.applyOnTheRight(k,k+1,rot);
}
}
}
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_SELFADJOINTEIGENSOLVER_H

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/*
Copyright (c) 2011, Intel Corporation. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its contributors may
be used to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
********************************************************************************
* Content : Eigen bindings to LAPACKe
* Self-adjoint eigenvalues/eigenvectors.
********************************************************************************
*/
#ifndef EIGEN_SAEIGENSOLVER_LAPACKE_H
#define EIGEN_SAEIGENSOLVER_LAPACKE_H
namespace Eigen {
/** \internal Specialization for the data types supported by LAPACKe */
#define EIGEN_LAPACKE_EIG_SELFADJ_2(EIGTYPE, LAPACKE_TYPE, LAPACKE_RTYPE, LAPACKE_NAME, EIGCOLROW ) \
template<> template<typename InputType> inline \
SelfAdjointEigenSolver<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >& \
SelfAdjointEigenSolver<Matrix<EIGTYPE, Dynamic, Dynamic, EIGCOLROW> >::compute(const EigenBase<InputType>& matrix, int options) \
{ \
eigen_assert(matrix.cols() == matrix.rows()); \
eigen_assert((options&~(EigVecMask|GenEigMask))==0 \
&& (options&EigVecMask)!=EigVecMask \
&& "invalid option parameter"); \
bool computeEigenvectors = (options&ComputeEigenvectors)==ComputeEigenvectors; \
lapack_int n = internal::convert_index<lapack_int>(matrix.cols()), lda, info; \
m_eivalues.resize(n,1); \
m_subdiag.resize(n-1); \
m_eivec = matrix; \
\
if(n==1) \
{ \
m_eivalues.coeffRef(0,0) = numext::real(m_eivec.coeff(0,0)); \
if(computeEigenvectors) m_eivec.setOnes(n,n); \
m_info = Success; \
m_isInitialized = true; \
m_eigenvectorsOk = computeEigenvectors; \
return *this; \
} \
\
lda = internal::convert_index<lapack_int>(m_eivec.outerStride()); \
char jobz, uplo='L'/*, range='A'*/; \
jobz = computeEigenvectors ? 'V' : 'N'; \
\
info = LAPACKE_##LAPACKE_NAME( LAPACK_COL_MAJOR, jobz, uplo, n, (LAPACKE_TYPE*)m_eivec.data(), lda, (LAPACKE_RTYPE*)m_eivalues.data() ); \
m_info = (info==0) ? Success : NoConvergence; \
m_isInitialized = true; \
m_eigenvectorsOk = computeEigenvectors; \
return *this; \
}
#define EIGEN_LAPACKE_EIG_SELFADJ(EIGTYPE, LAPACKE_TYPE, LAPACKE_RTYPE, LAPACKE_NAME ) \
EIGEN_LAPACKE_EIG_SELFADJ_2(EIGTYPE, LAPACKE_TYPE, LAPACKE_RTYPE, LAPACKE_NAME, ColMajor ) \
EIGEN_LAPACKE_EIG_SELFADJ_2(EIGTYPE, LAPACKE_TYPE, LAPACKE_RTYPE, LAPACKE_NAME, RowMajor )
EIGEN_LAPACKE_EIG_SELFADJ(double, double, double, dsyev)
EIGEN_LAPACKE_EIG_SELFADJ(float, float, float, ssyev)
EIGEN_LAPACKE_EIG_SELFADJ(dcomplex, lapack_complex_double, double, zheev)
EIGEN_LAPACKE_EIG_SELFADJ(scomplex, lapack_complex_float, float, cheev)
} // end namespace Eigen
#endif // EIGEN_SAEIGENSOLVER_H

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_TRIDIAGONALIZATION_H
#define EIGEN_TRIDIAGONALIZATION_H
namespace Eigen {
namespace internal {
template<typename MatrixType> struct TridiagonalizationMatrixTReturnType;
template<typename MatrixType>
struct traits<TridiagonalizationMatrixTReturnType<MatrixType> >
: public traits<typename MatrixType::PlainObject>
{
typedef typename MatrixType::PlainObject ReturnType; // FIXME shall it be a BandMatrix?
enum { Flags = 0 };
};
template<typename MatrixType, typename CoeffVectorType>
void tridiagonalization_inplace(MatrixType& matA, CoeffVectorType& hCoeffs);
}
/** \eigenvalues_module \ingroup Eigenvalues_Module
*
*
* \class Tridiagonalization
*
* \brief Tridiagonal decomposition of a selfadjoint matrix
*
* \tparam _MatrixType the type of the matrix of which we are computing the
* tridiagonal decomposition; this is expected to be an instantiation of the
* Matrix class template.
*
* This class performs a tridiagonal decomposition of a selfadjoint matrix \f$ A \f$ such that:
* \f$ A = Q T Q^* \f$ where \f$ Q \f$ is unitary and \f$ T \f$ a real symmetric tridiagonal matrix.
*
* A tridiagonal matrix is a matrix which has nonzero elements only on the
* main diagonal and the first diagonal below and above it. The Hessenberg
* decomposition of a selfadjoint matrix is in fact a tridiagonal
* decomposition. This class is used in SelfAdjointEigenSolver to compute the
* eigenvalues and eigenvectors of a selfadjoint matrix.
*
* Call the function compute() to compute the tridiagonal decomposition of a
* given matrix. Alternatively, you can use the Tridiagonalization(const MatrixType&)
* constructor which computes the tridiagonal Schur decomposition at
* construction time. Once the decomposition is computed, you can use the
* matrixQ() and matrixT() functions to retrieve the matrices Q and T in the
* decomposition.
*
* The documentation of Tridiagonalization(const MatrixType&) contains an
* example of the typical use of this class.
*
* \sa class HessenbergDecomposition, class SelfAdjointEigenSolver
*/
template<typename _MatrixType> class Tridiagonalization
{
public:
/** \brief Synonym for the template parameter \p _MatrixType. */
typedef _MatrixType MatrixType;
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
enum {
Size = MatrixType::RowsAtCompileTime,
SizeMinusOne = Size == Dynamic ? Dynamic : (Size > 1 ? Size - 1 : 1),
Options = MatrixType::Options,
MaxSize = MatrixType::MaxRowsAtCompileTime,
MaxSizeMinusOne = MaxSize == Dynamic ? Dynamic : (MaxSize > 1 ? MaxSize - 1 : 1)
};
typedef Matrix<Scalar, SizeMinusOne, 1, Options & ~RowMajor, MaxSizeMinusOne, 1> CoeffVectorType;
typedef typename internal::plain_col_type<MatrixType, RealScalar>::type DiagonalType;
typedef Matrix<RealScalar, SizeMinusOne, 1, Options & ~RowMajor, MaxSizeMinusOne, 1> SubDiagonalType;
typedef typename internal::remove_all<typename MatrixType::RealReturnType>::type MatrixTypeRealView;
typedef internal::TridiagonalizationMatrixTReturnType<MatrixTypeRealView> MatrixTReturnType;
typedef typename internal::conditional<NumTraits<Scalar>::IsComplex,
typename internal::add_const_on_value_type<typename Diagonal<const MatrixType>::RealReturnType>::type,
const Diagonal<const MatrixType>
>::type DiagonalReturnType;
typedef typename internal::conditional<NumTraits<Scalar>::IsComplex,
typename internal::add_const_on_value_type<typename Diagonal<const MatrixType, -1>::RealReturnType>::type,
const Diagonal<const MatrixType, -1>
>::type SubDiagonalReturnType;
/** \brief Return type of matrixQ() */
typedef HouseholderSequence<MatrixType,typename internal::remove_all<typename CoeffVectorType::ConjugateReturnType>::type> HouseholderSequenceType;
/** \brief Default constructor.
*
* \param [in] size Positive integer, size of the matrix whose tridiagonal
* decomposition will be computed.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via compute(). The \p size parameter is only
* used as a hint. It is not an error to give a wrong \p size, but it may
* impair performance.
*
* \sa compute() for an example.
*/
explicit Tridiagonalization(Index size = Size==Dynamic ? 2 : Size)
: m_matrix(size,size),
m_hCoeffs(size > 1 ? size-1 : 1),
m_isInitialized(false)
{}
/** \brief Constructor; computes tridiagonal decomposition of given matrix.
*
* \param[in] matrix Selfadjoint matrix whose tridiagonal decomposition
* is to be computed.
*
* This constructor calls compute() to compute the tridiagonal decomposition.
*
* Example: \include Tridiagonalization_Tridiagonalization_MatrixType.cpp
* Output: \verbinclude Tridiagonalization_Tridiagonalization_MatrixType.out
*/
template<typename InputType>
explicit Tridiagonalization(const EigenBase<InputType>& matrix)
: m_matrix(matrix.derived()),
m_hCoeffs(matrix.cols() > 1 ? matrix.cols()-1 : 1),
m_isInitialized(false)
{
internal::tridiagonalization_inplace(m_matrix, m_hCoeffs);
m_isInitialized = true;
}
/** \brief Computes tridiagonal decomposition of given matrix.
*
* \param[in] matrix Selfadjoint matrix whose tridiagonal decomposition
* is to be computed.
* \returns Reference to \c *this
*
* The tridiagonal decomposition is computed by bringing the columns of
* the matrix successively in the required form using Householder
* reflections. The cost is \f$ 4n^3/3 \f$ flops, where \f$ n \f$ denotes
* the size of the given matrix.
*
* This method reuses of the allocated data in the Tridiagonalization
* object, if the size of the matrix does not change.
*
* Example: \include Tridiagonalization_compute.cpp
* Output: \verbinclude Tridiagonalization_compute.out
*/
template<typename InputType>
Tridiagonalization& compute(const EigenBase<InputType>& matrix)
{
m_matrix = matrix.derived();
m_hCoeffs.resize(matrix.rows()-1, 1);
internal::tridiagonalization_inplace(m_matrix, m_hCoeffs);
m_isInitialized = true;
return *this;
}
/** \brief Returns the Householder coefficients.
*
* \returns a const reference to the vector of Householder coefficients
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* The Householder coefficients allow the reconstruction of the matrix
* \f$ Q \f$ in the tridiagonal decomposition from the packed data.
*
* Example: \include Tridiagonalization_householderCoefficients.cpp
* Output: \verbinclude Tridiagonalization_householderCoefficients.out
*
* \sa packedMatrix(), \ref Householder_Module "Householder module"
*/
inline CoeffVectorType householderCoefficients() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return m_hCoeffs;
}
/** \brief Returns the internal representation of the decomposition
*
* \returns a const reference to a matrix with the internal representation
* of the decomposition.
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* The returned matrix contains the following information:
* - the strict upper triangular part is equal to the input matrix A.
* - the diagonal and lower sub-diagonal represent the real tridiagonal
* symmetric matrix T.
* - the rest of the lower part contains the Householder vectors that,
* combined with Householder coefficients returned by
* householderCoefficients(), allows to reconstruct the matrix Q as
* \f$ Q = H_{N-1} \ldots H_1 H_0 \f$.
* Here, the matrices \f$ H_i \f$ are the Householder transformations
* \f$ H_i = (I - h_i v_i v_i^T) \f$
* where \f$ h_i \f$ is the \f$ i \f$th Householder coefficient and
* \f$ v_i \f$ is the Householder vector defined by
* \f$ v_i = [ 0, \ldots, 0, 1, M(i+2,i), \ldots, M(N-1,i) ]^T \f$
* with M the matrix returned by this function.
*
* See LAPACK for further details on this packed storage.
*
* Example: \include Tridiagonalization_packedMatrix.cpp
* Output: \verbinclude Tridiagonalization_packedMatrix.out
*
* \sa householderCoefficients()
*/
inline const MatrixType& packedMatrix() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return m_matrix;
}
/** \brief Returns the unitary matrix Q in the decomposition
*
* \returns object representing the matrix Q
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* This function returns a light-weight object of template class
* HouseholderSequence. You can either apply it directly to a matrix or
* you can convert it to a matrix of type #MatrixType.
*
* \sa Tridiagonalization(const MatrixType&) for an example,
* matrixT(), class HouseholderSequence
*/
HouseholderSequenceType matrixQ() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return HouseholderSequenceType(m_matrix, m_hCoeffs.conjugate())
.setLength(m_matrix.rows() - 1)
.setShift(1);
}
/** \brief Returns an expression of the tridiagonal matrix T in the decomposition
*
* \returns expression object representing the matrix T
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* Currently, this function can be used to extract the matrix T from internal
* data and copy it to a dense matrix object. In most cases, it may be
* sufficient to directly use the packed matrix or the vector expressions
* returned by diagonal() and subDiagonal() instead of creating a new
* dense copy matrix with this function.
*
* \sa Tridiagonalization(const MatrixType&) for an example,
* matrixQ(), packedMatrix(), diagonal(), subDiagonal()
*/
MatrixTReturnType matrixT() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return MatrixTReturnType(m_matrix.real());
}
/** \brief Returns the diagonal of the tridiagonal matrix T in the decomposition.
*
* \returns expression representing the diagonal of T
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* Example: \include Tridiagonalization_diagonal.cpp
* Output: \verbinclude Tridiagonalization_diagonal.out
*
* \sa matrixT(), subDiagonal()
*/
DiagonalReturnType diagonal() const;
/** \brief Returns the subdiagonal of the tridiagonal matrix T in the decomposition.
*
* \returns expression representing the subdiagonal of T
*
* \pre Either the constructor Tridiagonalization(const MatrixType&) or
* the member function compute(const MatrixType&) has been called before
* to compute the tridiagonal decomposition of a matrix.
*
* \sa diagonal() for an example, matrixT()
*/
SubDiagonalReturnType subDiagonal() const;
protected:
MatrixType m_matrix;
CoeffVectorType m_hCoeffs;
bool m_isInitialized;
};
template<typename MatrixType>
typename Tridiagonalization<MatrixType>::DiagonalReturnType
Tridiagonalization<MatrixType>::diagonal() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return m_matrix.diagonal().real();
}
template<typename MatrixType>
typename Tridiagonalization<MatrixType>::SubDiagonalReturnType
Tridiagonalization<MatrixType>::subDiagonal() const
{
eigen_assert(m_isInitialized && "Tridiagonalization is not initialized.");
return m_matrix.template diagonal<-1>().real();
}
namespace internal {
/** \internal
* Performs a tridiagonal decomposition of the selfadjoint matrix \a matA in-place.
*
* \param[in,out] matA On input the selfadjoint matrix. Only the \b lower triangular part is referenced.
* On output, the strict upper part is left unchanged, and the lower triangular part
* represents the T and Q matrices in packed format has detailed below.
* \param[out] hCoeffs returned Householder coefficients (see below)
*
* On output, the tridiagonal selfadjoint matrix T is stored in the diagonal
* and lower sub-diagonal of the matrix \a matA.
* The unitary matrix Q is represented in a compact way as a product of
* Householder reflectors \f$ H_i \f$ such that:
* \f$ Q = H_{N-1} \ldots H_1 H_0 \f$.
* The Householder reflectors are defined as
* \f$ H_i = (I - h_i v_i v_i^T) \f$
* where \f$ h_i = hCoeffs[i]\f$ is the \f$ i \f$th Householder coefficient and
* \f$ v_i \f$ is the Householder vector defined by
* \f$ v_i = [ 0, \ldots, 0, 1, matA(i+2,i), \ldots, matA(N-1,i) ]^T \f$.
*
* Implemented from Golub's "Matrix Computations", algorithm 8.3.1.
*
* \sa Tridiagonalization::packedMatrix()
*/
template<typename MatrixType, typename CoeffVectorType>
void tridiagonalization_inplace(MatrixType& matA, CoeffVectorType& hCoeffs)
{
using numext::conj;
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::RealScalar RealScalar;
Index n = matA.rows();
eigen_assert(n==matA.cols());
eigen_assert(n==hCoeffs.size()+1 || n==1);
for (Index i = 0; i<n-1; ++i)
{
Index remainingSize = n-i-1;
RealScalar beta;
Scalar h;
matA.col(i).tail(remainingSize).makeHouseholderInPlace(h, beta);
// Apply similarity transformation to remaining columns,
// i.e., A = H A H' where H = I - h v v' and v = matA.col(i).tail(n-i-1)
matA.col(i).coeffRef(i+1) = 1;
hCoeffs.tail(n-i-1).noalias() = (matA.bottomRightCorner(remainingSize,remainingSize).template selfadjointView<Lower>()
* (conj(h) * matA.col(i).tail(remainingSize)));
hCoeffs.tail(n-i-1) += (conj(h)*RealScalar(-0.5)*(hCoeffs.tail(remainingSize).dot(matA.col(i).tail(remainingSize)))) * matA.col(i).tail(n-i-1);
matA.bottomRightCorner(remainingSize, remainingSize).template selfadjointView<Lower>()
.rankUpdate(matA.col(i).tail(remainingSize), hCoeffs.tail(remainingSize), Scalar(-1));
matA.col(i).coeffRef(i+1) = beta;
hCoeffs.coeffRef(i) = h;
}
}
// forward declaration, implementation at the end of this file
template<typename MatrixType,
int Size=MatrixType::ColsAtCompileTime,
bool IsComplex=NumTraits<typename MatrixType::Scalar>::IsComplex>
struct tridiagonalization_inplace_selector;
/** \brief Performs a full tridiagonalization in place
*
* \param[in,out] mat On input, the selfadjoint matrix whose tridiagonal
* decomposition is to be computed. Only the lower triangular part referenced.
* The rest is left unchanged. On output, the orthogonal matrix Q
* in the decomposition if \p extractQ is true.
* \param[out] diag The diagonal of the tridiagonal matrix T in the
* decomposition.
* \param[out] subdiag The subdiagonal of the tridiagonal matrix T in
* the decomposition.
* \param[in] extractQ If true, the orthogonal matrix Q in the
* decomposition is computed and stored in \p mat.
*
* Computes the tridiagonal decomposition of the selfadjoint matrix \p mat in place
* such that \f$ mat = Q T Q^* \f$ where \f$ Q \f$ is unitary and \f$ T \f$ a real
* symmetric tridiagonal matrix.
*
* The tridiagonal matrix T is passed to the output parameters \p diag and \p subdiag. If
* \p extractQ is true, then the orthogonal matrix Q is passed to \p mat. Otherwise the lower
* part of the matrix \p mat is destroyed.
*
* The vectors \p diag and \p subdiag are not resized. The function
* assumes that they are already of the correct size. The length of the
* vector \p diag should equal the number of rows in \p mat, and the
* length of the vector \p subdiag should be one left.
*
* This implementation contains an optimized path for 3-by-3 matrices
* which is especially useful for plane fitting.
*
* \note Currently, it requires two temporary vectors to hold the intermediate
* Householder coefficients, and to reconstruct the matrix Q from the Householder
* reflectors.
*
* Example (this uses the same matrix as the example in
* Tridiagonalization::Tridiagonalization(const MatrixType&)):
* \include Tridiagonalization_decomposeInPlace.cpp
* Output: \verbinclude Tridiagonalization_decomposeInPlace.out
*
* \sa class Tridiagonalization
*/
template<typename MatrixType, typename DiagonalType, typename SubDiagonalType>
void tridiagonalization_inplace(MatrixType& mat, DiagonalType& diag, SubDiagonalType& subdiag, bool extractQ)
{
eigen_assert(mat.cols()==mat.rows() && diag.size()==mat.rows() && subdiag.size()==mat.rows()-1);
tridiagonalization_inplace_selector<MatrixType>::run(mat, diag, subdiag, extractQ);
}
/** \internal
* General full tridiagonalization
*/
template<typename MatrixType, int Size, bool IsComplex>
struct tridiagonalization_inplace_selector
{
typedef typename Tridiagonalization<MatrixType>::CoeffVectorType CoeffVectorType;
typedef typename Tridiagonalization<MatrixType>::HouseholderSequenceType HouseholderSequenceType;
template<typename DiagonalType, typename SubDiagonalType>
static void run(MatrixType& mat, DiagonalType& diag, SubDiagonalType& subdiag, bool extractQ)
{
CoeffVectorType hCoeffs(mat.cols()-1);
tridiagonalization_inplace(mat,hCoeffs);
diag = mat.diagonal().real();
subdiag = mat.template diagonal<-1>().real();
if(extractQ)
mat = HouseholderSequenceType(mat, hCoeffs.conjugate())
.setLength(mat.rows() - 1)
.setShift(1);
}
};
/** \internal
* Specialization for 3x3 real matrices.
* Especially useful for plane fitting.
*/
template<typename MatrixType>
struct tridiagonalization_inplace_selector<MatrixType,3,false>
{
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::RealScalar RealScalar;
template<typename DiagonalType, typename SubDiagonalType>
static void run(MatrixType& mat, DiagonalType& diag, SubDiagonalType& subdiag, bool extractQ)
{
using std::sqrt;
const RealScalar tol = (std::numeric_limits<RealScalar>::min)();
diag[0] = mat(0,0);
RealScalar v1norm2 = numext::abs2(mat(2,0));
if(v1norm2 <= tol)
{
diag[1] = mat(1,1);
diag[2] = mat(2,2);
subdiag[0] = mat(1,0);
subdiag[1] = mat(2,1);
if (extractQ)
mat.setIdentity();
}
else
{
RealScalar beta = sqrt(numext::abs2(mat(1,0)) + v1norm2);
RealScalar invBeta = RealScalar(1)/beta;
Scalar m01 = mat(1,0) * invBeta;
Scalar m02 = mat(2,0) * invBeta;
Scalar q = RealScalar(2)*m01*mat(2,1) + m02*(mat(2,2) - mat(1,1));
diag[1] = mat(1,1) + m02*q;
diag[2] = mat(2,2) - m02*q;
subdiag[0] = beta;
subdiag[1] = mat(2,1) - m01 * q;
if (extractQ)
{
mat << 1, 0, 0,
0, m01, m02,
0, m02, -m01;
}
}
}
};
/** \internal
* Trivial specialization for 1x1 matrices
*/
template<typename MatrixType, bool IsComplex>
struct tridiagonalization_inplace_selector<MatrixType,1,IsComplex>
{
typedef typename MatrixType::Scalar Scalar;
template<typename DiagonalType, typename SubDiagonalType>
static void run(MatrixType& mat, DiagonalType& diag, SubDiagonalType&, bool extractQ)
{
diag(0,0) = numext::real(mat(0,0));
if(extractQ)
mat(0,0) = Scalar(1);
}
};
/** \internal
* \eigenvalues_module \ingroup Eigenvalues_Module
*
* \brief Expression type for return value of Tridiagonalization::matrixT()
*
* \tparam MatrixType type of underlying dense matrix
*/
template<typename MatrixType> struct TridiagonalizationMatrixTReturnType
: public ReturnByValue<TridiagonalizationMatrixTReturnType<MatrixType> >
{
public:
/** \brief Constructor.
*
* \param[in] mat The underlying dense matrix
*/
TridiagonalizationMatrixTReturnType(const MatrixType& mat) : m_matrix(mat) { }
template <typename ResultType>
inline void evalTo(ResultType& result) const
{
result.setZero();
result.template diagonal<1>() = m_matrix.template diagonal<-1>().conjugate();
result.diagonal() = m_matrix.diagonal();
result.template diagonal<-1>() = m_matrix.template diagonal<-1>();
}
Index rows() const { return m_matrix.rows(); }
Index cols() const { return m_matrix.cols(); }
protected:
typename MatrixType::Nested m_matrix;
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_TRIDIAGONALIZATION_H