Parameters
Table below list the VRPSolver parameters available to the user. In addition the user may provide the following information to improve the solver performance.
- Designation of the first main resource which will be used for the bi-directional labelling.
- Priorities for branching strategies.
- Distance matrix between elementarity sets for defining initial $ng$-sets and for local search heuristic separation of $l$-row rank-1 cuts with $l\geq 5$.
| Parameter | Description | Default value |
|---|---|---|
| GlobalTimeLimit | User time limit for the execution | 21474836 seconds |
| MaxNbOfBBtreeNodeTreated | Max number of nodes in the b&b tree | 100000 |
| RCSPstopCutGenTimeThresholdInPricing | Time threshold for the labeling algorithm | 10 seconds |
| RCSPhardTimeThresholdInPricing | Time threshold for the labeling algorithm | 20 seconds |
| RCSPnumberOfBucketsPerVertex | Calculation of step size for buckets | 25 |
| RCSPdynamicBucketSteps | Calculation of step size for buckets | 1 (on) |
| RCSPuseBidirectionalSearch | Bi-directional search | 2 |
| RCSPapplyReducedCostFixing | Bucket arc elimination | 1 (on) |
| RCSPmaxNumOfColsPerExactIteration | Max. # of generated columns per iteration | 150 |
| RCSPmaxNumOfColsPerIteration | Max. # of generated columns per iteration | 30 |
| StabilizationMinPhaseOfStage | Minimum stage for stabilization | 0 (everywhere) |
| RCSPmaxNumOfLabelsInEnumeration | Max. # of labels in the enumeration | 1000000 |
| RCSPmaxNumOfEnumeratedSolutions | Max. # of paths in the enumeration | 1000000 |
| RCSPmaxNumOfEnumSolutionsForMIP | Max. total # of enumerated paths for MIP | 10000 |
| RCSPmaxNumOfEnumSolsForEndOfNodeMIP | Max. total # of enumerated paths for MIP at the end of a node | 10000 |
| RCSPinitNGneighbourhoodSize | Initial size of ng-sets | 8 |
| RCSPmaxNGneighbourhoodSize | Maximum size of ng-sets | 8 |
| RCSPrankOneCutsMaxNumPerRound | Limited-memory rank-1 cuts parameter 1 | 100 |
| RCSPrankOneCutsMaxNumRows | Limited-memory rank-1 cuts parameter 2 | 5 |
| RCSPrankOneCutsMemoryType | Limited-memory rank-1 cuts parameter 3 | 2 |
| RCSPallowRoutesWithSameVerticesSet | Avoid inserting routes with the same set of vertices from the same pricing into the Master LP. | true (on) |
| RCSPredCostFixingFalseGap | Edge and path elimination based on a false gap FG=(UB-LB)/RCSPredCostFixingFalseGap | 0 (off) |
| RCSPmaxNumOfLabelsInHeurEnumeration | Max. number of labels in the heuristic enumeration. | – (MaxTimeForRestrictedMasterIpHeur must be active) |
| CutTailingOffThreshold | Cut generation tailing-off parameter 1 | 0.02 (2%) |
| CutTailingOffCounterThreshold | Cut generation tailing-off parameter 2 | 3 |
| SafeDualBoundScaleFactor | Numerically safe dual bound multiplier | -1 (off) |
| StrongBranchingPhaseOneCandidatesNumber | Strong branching parameter for phase 1 | 100 |
| StrongBranchingPhaseOneTreeSizeEstimRatio | Strong branching parameter for phase 1 | 0.3 |
| StrongBranchingPhaseTwoCandidatesNumber | Strong branching parameter for phase 2 | 3 |
| StrongBranchingPhaseTwoTreeSizeEstimRatio | Strong branching parameter for phase 2 | 0.1 |
| MaxTimeForRestrictedMasterIpHeur | Restricted master heuristic | -1 (off) |
| DivingHeurUseDepthLimit | Diving heuristic (with LDS) | -1 (off) |
| MaxLDSdepth | Diving heuristic (with LDS) | 0 |
| MaxLDSbreadth | Diving heuristic (with LDS) | 0 |
| CallFrequencyOfRestrictedMasterIpHeur | Frequency (in terms of nodes) in which the restricted master heuristic is invoked (it is first called at the root node) | – (MaxTimeForRestrictedMasterIpHeur must be active) |
| MIPemphasisInRestrictedMasterIpHeur | Set the MIP solver to concentrate on improving primal bound at the expense of improving lower bound. | – (MaxTimeForRestrictedMasterIpHeur must be active) |
| MaxNumEnumSolsInRestrictedMasterIpHeur | Max. number of enumerated solutions in the restricted master heuristic. | – (MaxTimeForRestrictedMasterIpHeur must be active) |