use weights to find better sequence with TTG and TTL constraints
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@@ -18,15 +18,24 @@ class Ant:
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self.Configuration = configuration
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self.RunwayManager = RunwayManager(self.Configuration)
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self.InboundSelected = [ False ] * len(self.Configuration.Inbounds)
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self.InboundScore = np.zeros([ len(self.Configuration.Inbounds), 1 ])
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self.PheromoneMatrix = pheromoneTable
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self.SequenceDelay = timedelta(seconds = 0)
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self.Sequence = None
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def qualifyDelay(delay, inbound, runway):
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if 0.0 > delay.total_seconds():
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delay = timedelta(seconds = 0)
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# calculate the heuristic scaling to punish increased delays for single inbounds
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scaledDelay = delay.total_seconds() / inbound.ArrivalCandidates[runway.Name].MaximumTimeToLose.total_seconds()
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return max(1.0 / (99.0 * (scaledDelay ** 2) + 1), 0.01)
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# Implements function (5), but adapted to the following logic:
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# An adaption of the heuristic function is used:
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# - Calculates the unused runway time (time between two consecutive landings)
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# - Calculates a ratio between the inbound delay and the unused runway time
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# - Adds the current overal sequence delay to the heuristic function
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# - Weight the overall ratio based on maximum time to lose to punish high time to lose rates while other flights are gaining time
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def heuristicInformation(self, preceeding : int, current : int):
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rwy, eta, unusedRunwayTime = self.RunwayManager.selectArrivalRunway(self.Configuration.Inbounds[current], True, self.Configuration.EarliestArrivalTime)
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inboundDelay = eta - self.Configuration.Inbounds[current].ArrivalCandidates[rwy.Name].InitialArrivalTime
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@@ -39,7 +48,10 @@ class Ant:
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fraction += self.SequenceDelay.total_seconds()
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fraction /= 60.0
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return self.PheromoneMatrix[preceeding, current] * ((1.0 / (fraction or 1)) ** self.Configuration.Beta)
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# calculate the heuristic scaling to punish increased delays for single inbounds
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weight = Ant.qualifyDelay(inboundDelay, self.Configuration.Inbounds[current], rwy)
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return weight * self.PheromoneMatrix[preceeding, current] * ((1.0 / (fraction or 1)) ** self.Configuration.Beta)
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# Implements functions (3), (6)
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def selectNextLandingIndex(self, preceedingIndex : int):
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@@ -57,13 +69,9 @@ class Ant:
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if False == self.InboundSelected[i]:
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pheromoneScale += self.heuristicInformation(preceedingIndex, i)
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# fallback
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if 0.0 >= pheromoneScale:
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pheromoneScale = 1.0
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for i in range(0, len(self.InboundSelected)):
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if False == self.InboundSelected[i]:
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weights.append(self.heuristicInformation(preceedingIndex, i) / pheromoneScale)
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weights.append(self.heuristicInformation(preceedingIndex, i) / (pheromoneScale or 1))
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total = sum(weights)
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cumdist = list(itertools.accumulate(weights)) + [total]
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@@ -91,17 +99,19 @@ class Ant:
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delay = inbound.PlannedArrivalTime - inbound.InitialArrivalTime
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if 0.0 < delay.total_seconds():
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return delay
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return delay, rwy
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else:
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return timedelta(seconds = 0)
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return timedelta(seconds = 0), rwy
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def findSolution(self, first : int):
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self.Sequence = []
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# select the first inbound
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self.InboundSelected[first] = True
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delay, rwy = self.associateInbound(self.Configuration.Inbounds[first], self.Configuration.EarliestArrivalTime)
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self.InboundScore[0] = Ant.qualifyDelay(delay, self.Configuration.Inbounds[first], rwy)
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self.Sequence.append(first)
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self.SequenceDelay += self.associateInbound(self.Configuration.Inbounds[first], self.Configuration.EarliestArrivalTime)
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self.SequenceDelay += delay
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while 1:
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index = self.selectNextLandingIndex(self.Sequence[-1])
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@@ -109,7 +119,9 @@ class Ant:
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break
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self.InboundSelected[index] = True
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self.SequenceDelay += self.associateInbound(self.Configuration.Inbounds[index], self.Configuration.EarliestArrivalTime)
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delay, rwy = self.associateInbound(self.Configuration.Inbounds[index], self.Configuration.EarliestArrivalTime)
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self.SequenceDelay += delay
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self.InboundScore[len(self.Sequence)] = Ant.qualifyDelay(delay, self.Configuration.Inbounds[index], rwy)
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self.Sequence.append(index)
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# update the local pheromone
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@@ -120,4 +132,7 @@ class Ant:
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# validate that nothing went wrong
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if len(self.Sequence) != len(self.Configuration.Inbounds):
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self.SequenceDelay = None
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self.SequenceScore = None
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self.Sequence = None
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else:
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self.SequenceScore = np.median(self.InboundScore)
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@@ -35,7 +35,8 @@ class Colony:
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# TODO remove this after testing and optimization
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for runway in inbound.ArrivalCandidates:
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inbound.ArrivalCandidates[runway].InitialArrivalTime = tmp
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inbound.ArrivalCandidates[runway].EarliestArrivalTime = tmp
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inbound.ArrivalCandidates[runway].EarliestArrivalTime = tmp - inbound.ArrivalCandidates[runway].MaximumTimeToGain
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inbound.ArrivalCandidates[runway].LatestArrivalTime = tmp + inbound.ArrivalCandidates[runway].MaximumTimeToLose
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tmp += timedelta(seconds = 20)
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Colony.associateInbound(rwyManager, inbound, earliestArrivalTime, False)
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overallDelay += inbound.PlannedArrivalTime - inbound.InitialArrivalTime
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@@ -83,19 +84,26 @@ class Colony:
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ant.findSolution(index)
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# fallback to check if findSolution was successful
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if None == ant.SequenceDelay or None == ant.Sequence:
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if None == ant.SequenceDelay or None == ant.Sequence or None == ant.SequenceScore:
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sys.stderr.write('Invalid ANT run detected!')
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sys.exit(-1)
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candidates.append([ ant.SequenceDelay, ant.Sequence ])
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candidates.append(
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[
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ant.SequenceDelay,
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ant.Sequence,
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ant.SequenceScore,
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ant.SequenceDelay.total_seconds() / ant.SequenceScore
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]
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)
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# find the best solution in all candidates of this generation
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bestCandidate = None
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for candidate in candidates:
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if None == bestCandidate or candidate[0] < bestCandidate[0]:
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if None == bestCandidate or candidate[3] < bestCandidate[3]:
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bestCandidate = candidate
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dTheta = 1.0 / (candidate[0].total_seconds() / 60.0)
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dTheta = 1.0 / ((candidate[0].total_seconds() / 60.0) or 1.0)
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for i in range(1, len(candidate[1])):
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update = (1.0 - self.Configuration.Epsilon) * self.PheromoneMatrix[candidate[1][i - 1], candidate[1][i]] + dTheta
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self.PheromoneMatrix[candidate[1][i - 1], candidate[1][i]] = max(update, self.Configuration.ThetaZero)
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