Scippy

SCIP

Solving Constraint Integer Programs

heur_local.h File Reference

Detailed Description

Improvement heuristic for Steiner problems.

Author
Daniel Rehfeldt

This file implements three local search heuristics, namely vertex insertion, key-path exchange and key-vertex elimination, see "Fast Local Search for Steiner Trees in Graphs" by Uchoa and Werneck. Furthermore, it includes several non-published local search heuristics for prize-collecting Steiner problem tree variants.

Definition in file heur_local.h.

#include "scip/scip.h"
#include "grph.h"

Go to the source code of this file.

Functions

SCIP_RETCODE SCIPStpIncludeHeurLocal (SCIP *scip)
 
SCIP_RETCODE SCIPStpHeurLocalRun (SCIP *scip, GRAPH *graph, const SCIP_Real *cost, int *best_result)
 
SCIP_RETCODE SCIPStpHeurLocalExtendPcMw (SCIP *scip, GRAPH *graph, const SCIP_Real *cost, PATH *path, int *stedge, STP_Bool *stvertex, SCIP_Bool *extensions)
 

Function Documentation

◆ SCIPStpIncludeHeurLocal()

◆ SCIPStpHeurLocalRun()

SCIP_RETCODE SCIPStpHeurLocalRun ( SCIP scip,
GRAPH graph,
const SCIP_Real cost,
int *  best_result 
)

perform local heuristics on a given Steiner tree

perform local heuristics on a given Steiner tree todo delete cost parameter

Key-Path Exchange

Parameters
scipSCIP data structure
graphgraph data structure
costarc cost array todo delete this parameter and use graph->cost
best_resultarray indicating whether an arc is part of the solution (CONNECTED/UNKNOWN)

Definition at line 208 of file heur_local.c.

References BMSclearMemoryArray, CONNECT, GRAPH::cost, dfsorder(), shortest_path::dist, EAT_FREE, EAT_LAST, ST_Node::edge, shortest_path::edge, GRAPH::edges, FALSE, FARAWAY, flipedge, GRAPH::grad, graph_edge_add(), graph_free(), graph_init(), graph_knot_add(), graph_path_exec(), graph_path_exit(), graph_path_init(), graph_sol_getObj(), graph_sol_valid(), graph_valid(), graph_voronoi(), graph_voronoiRepair(), graph_voronoiRepairMult(), GRAPH::head, heap_add(), GRAPH::ieat, Int_List_Node::index, GRAPH::inpbeg, Is_pterm, Is_term, GRAPH::knots, lca(), GRAPH::mark, MST_MODE, nnodes, nodeIsCrucial(), NULL, GRAPH::oeat, GRAPH::outbeg, ST_Node::parent, Int_List_Node::parent, GRAPH::path_heap, GRAPH::path_state, GRAPH::prize, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBlockMemory, SCIPallocBufferArray, SCIPdebugMessage, SCIPfreeBlockMemory, SCIPfreeBufferArray, SCIPisGT(), SCIPisLE(), SCIPisLT(), SCIPisNegative(), SCIPisPositive(), SCIPlinkcuttreeCut(), SCIPlinkcuttreeEvert(), SCIPlinkcuttreeFindMax(), SCIPlinkcuttreeFindMinChain(), SCIPlinkcuttreeInit(), SCIPlinkcuttreeLink(), SCIPpairheapDeletemin(), SCIPpairheapFree(), SCIPpairheapInsert(), SCIPpairheapMeldheaps(), SCIPStpHeurLocalExtendPcMw(), SCIPStpHeurTMPrune(), SCIPStpHeurTMPrunePc(), SCIPStpunionfindClear(), SCIPStpunionfindFind(), SCIPStpunionfindFree(), SCIPStpunionfindInit(), SCIPStpunionfindUnion(), GRAPH::source, STP_GSTP, STP_MWCSP, STP_OARSMT, STP_PCSPG, STP_RPCSPG, STP_RSMT, STP_SPG, GRAPH::stp_type, GRAPH::tail, GRAPH::term, GRAPH::terms, TRUE, and UNKNOWN.

Referenced by computeDaSolPcMw(), computeNewSols(), computePertubedSol(), reduce_da(), reduce_daPcMw(), SCIP_DECL_HEUREXEC(), SCIPStpHeurAscendPruneRun(), SCIPStpHeurPruneUpdateSols(), SCIPStpHeurRecRun(), SCIPStpHeurSlackPruneRun(), and selectBranchingVertexBySol().

◆ SCIPStpHeurLocalExtendPcMw()

SCIP_RETCODE SCIPStpHeurLocalExtendPcMw ( SCIP scip,
GRAPH graph,
const SCIP_Real cost,
PATH path,
int *  stedge,
STP_Bool stvertex,
SCIP_Bool extensions 
)

greedy extension local heuristic for (R)PC and MW

Greedy Extension local heuristic for (R)PC and MW

Parameters
scipSCIP data structure
graphgraph data structure
costedge cost array
pathshortest data structure array
stedgeinitialized array to indicate whether an edge is part of the Steiner tree
stvertexuninitialized array to indicate whether a vertex is part of the Steiner tree
extensionspointer to store whether extensions have been made

Definition at line 1693 of file heur_local.c.

References BMSclearMemoryArray, BMScopyMemoryArray, CONNECT, GRAPH::cost, Graph_Node::dist, shortest_path::dist, EAT_LAST, shortest_path::edge, GRAPH::edges, FALSE, GNODECmpByDist(), GRAPH::grad, graph_path_st_pcmw_extend(), graph_pc_2transcheck(), GREEDY_EXTENSIONS, GREEDY_EXTENSIONS_MW, GREEDY_MAXRESTARTS, GRAPH::head, GRAPH::ieat, GRAPH::inpbeg, Is_pterm, Is_term, GRAPH::knots, MAX, nnodes, NULL, Graph_Node::number, GRAPH::prize, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPdebugMessage, SCIPfreeBufferArray, SCIPisLT(), SCIPpqueueCreate(), SCIPpqueueFirst(), SCIPpqueueFree(), SCIPpqueueInsert(), SCIPpqueueNElems(), SCIPpqueueRemove(), SCIPStpHeurTMPrunePc(), GRAPH::source, STP_MWCSP, GRAPH::stp_type, GRAPH::tail, GRAPH::term, TRUE, and UNKNOWN.

Referenced by SCIPStpHeurLocalRun().