Package org.goplanit.assignment.ltm.sltm

Class PasManager

  • public class PasManager
extends Object
    Container class for tracking all unique PASs indexed by their last (merge) vertex
    Author:
    markr

    • Constructor Detail

      • PasManager

        public PasManager()
        Constructor

    • Method Detail

      • createSubpathArrayFrom

        public static EdgeSegment[] createSubpathArrayFrom​(DirectedVertex start,
                                                   DirectedVertex end,
                                                   ShortestPathResult pathTree,
                                                   int arrayLength,
                                                   boolean truncateArray)
        Extract a subpath in the form of a raw edge segment array from start to end vertex based on the shortest path result provided. Since the path tree is in reverse direction, the array is filled from the back, i.e.,if there is spare capacity the front of the array would be empty.
        Parameters:
        start - start vertex upstream
        end - end vertex downstream
        pathTree - to extract path from, tree is in upstream direction
        arrayLength - to use for the to be created array which should be at least as long as the path that is to be extracted
        truncateArray - flag indicating to truncate the subpath array in case the front of the array is not fully used due to the existence of spare capacity
        Returns:
        created array, null if no path could be found

      • createSubpathArrayFrom

        public static EdgeSegment[] createSubpathArrayFrom​(DirectedVertex start,
                                                   DirectedVertex end,
                                                   Map<DirectedVertex,​EdgeSegment> pathTree,
                                                   int arrayLength,
                                                   boolean truncateArray)
        Extract a subpath in the form of a raw edge segment array from start to end vertex based on a map representing a tree with succeeding edge segments for each vertex
        Parameters:
        start - start vertex upstream
        end - end vertex downstream
        pathTree - to extract path from, tree is in downstream direction
        arrayLength - to use for the to be created array which should be at least as long as the path that is to be extracted
        truncateArray - flag indicating to truncate the subpath array in case the back of the array is not fully used due to the existence of spare capacity
        Returns:
        created array, null if no path could be found

      • createNewPas

        public Pas createNewPas​(Bush originBush,
                        EdgeSegment[] s1,
                        EdgeSegment[] s2)
        create a new PAS for the given cheap and expensive paired alternative segments (subpaths) and register the origin bush on it that was responsible for creating it
        Parameters:
        originBush - responsible for triggering the creation of this PAS
        s1 - cheap alternative segment
        s2 - expensive alternative segment
        Returns:
        createdPas

      • removePas

        public void removePas​(Pas pas)
        Remove the PAS from the manager
        Parameters:
        pas - to remove

      • getPassByMergeVertex

        public Collection<Pas> getPassByMergeVertex​(DirectedVertex mergeVertex)
        Collect all PASs that share the same merge (end) vertex
        Parameters:
        mergeVertex - to collect for
        Returns:
        found PAS matches

      • findFirstSuitableExistingPas

        public Pas findFirstSuitableExistingPas​(Bush originBush,
                                        DirectedVertex mergeVertex,
                                        double[] flowAcceptanceFactors,
                                        double reducedCost)
        find the first PAS which has the given merge vertex as end vertex and which if we would extend the bush with its least cost alternative would improve to the point it is considered effective enough compared to the upper bound (reduced cost) improvement provided as well as that the bush has sufficient flow on the high cost alternative of the PAS such that it can improve sufficiently by shifting flow towards the new low cost segment. If this all holds the PAS is selected and returned. We select the first PAS we can find that matches this criteria.
        Parameters:
        originBush - to find suitable PAS for
        mergeVertex - to use
        flowAcceptanceFactors - to use (required to assess flow effectiveness in capacitated context)
        reducedCost - the upper bound on the improvement that is known for this merge vertex
        Returns:
        pas found, null if no suitable candidates exist

      • updateCosts

        public void updateCosts​(double[] linkSegmentCosts)
        Update costs on all registered PASs
        Parameters:
        linkSegmentCosts - to use

      • updateCosts

        public void updateCosts​(Collection<Pas> pass,
                        double[] linkSegmentCosts)
        Update cost for a selection of PASs only
        Parameters:
        pass - collection of specific PASs to update
        linkSegmentCosts - to use

      • getPassSortedByReducedCost

        public PriorityQueue<Pas> getPassSortedByReducedCost()
        Construct a priority queue based on the PASs reduced cost, i.e., difference between their high and low cost segments in descending order.
        Returns:
        sorted PAS queue

      • forEachPas

        public void forEachPas​(Consumer<Pas> pasConsumer)
        Loop over all Pass
        Parameters:
        pasConsumer - to apply