Scippy

SCIP

Solving Constraint Integer Programs

heur_local.c File Reference

Detailed Description

Improvement heuristic for Steiner problems.

Author
Daniel Rehfeldt

This file implements several local heuristics, including vertex insertion, key-path exchange and key-vertex elimination, ("Fast Local Search for Steiner Trees in Graphs" by Uchoa and Werneck). Other heuristics are for PCSTP and MWCSP.

A list of all interface methods can be found in heur_local.h.

Definition in file heur_local.c.

#include <assert.h>
#include <string.h>
#include "heur_local.h"
#include "heur_tm.h"
#include "probdata_stp.h"

Go to the source code of this file.

Macros

#define HEUR_NAME   "local"
 
#define HEUR_DESC   "improvement heuristic for STP"
 
#define HEUR_DISPCHAR   '-'
 
#define HEUR_PRIORITY   100
 
#define HEUR_FREQ   1
 
#define HEUR_FREQOFS   0
 
#define HEUR_MAXDEPTH   -1
 
#define HEUR_TIMING   (SCIP_HEURTIMING_BEFORENODE | SCIP_HEURTIMING_DURINGLPLOOP | SCIP_HEURTIMING_AFTERLPLOOP | SCIP_HEURTIMING_AFTERNODE)
 
#define HEUR_USESSUBSCIP   FALSE
 
#define DEFAULT_DURINGROOT   TRUE
 
#define DEFAULT_MAXFREQLOC   FALSE
 
#define DEFAULT_MAXNBESTSOLS   25
 
#define DEFAULT_NBESTSOLS   10
 
#define DEFAULT_MINNBESTSOLS   6
 
#define LOCAL_MAXRESTARTS   5
 
#define GREEDY_MAXRESTARTS   3
 
#define GREEDY_EXTENSIONS_MW   6
 
#define GREEDY_EXTENSIONS   5
 

Functions

static void dfsorder (const GRAPH *graph, const int *edges, const int *node, int *counter, int *dfst)
 
static SCIP_RETCODE lca (SCIP *scip, const GRAPH *graph, int u, UF *uf, STP_Bool *nodesmark, int *steineredges, IDX **lcalists, PHNODE **boundpaths, int *heapsize, int *vbase)
 
static STP_Bool nodeIsCrucial (const GRAPH *graph, int *steineredges, int node)
 
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)
 
static SCIP_DECL_HEURCOPY (heurCopyLocal)
 
static SCIP_DECL_HEURFREE (heurFreeLocal)
 
static SCIP_DECL_HEURINITSOL (heurInitsolLocal)
 
static SCIP_DECL_HEUREXITSOL (heurExitsolLocal)
 
static SCIP_DECL_HEUREXEC (heurExecLocal)
 
SCIP_RETCODE SCIPStpIncludeHeurLocal (SCIP *scip)
 

Macro Definition Documentation

◆ HEUR_NAME

◆ HEUR_DESC

#define HEUR_DESC   "improvement heuristic for STP"

Definition at line 42 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   '-'

Definition at line 43 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   100

Definition at line 44 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_FREQ

#define HEUR_FREQ   1

Definition at line 45 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   0

Definition at line 46 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 47 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ HEUR_TIMING

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 50 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ DEFAULT_DURINGROOT

#define DEFAULT_DURINGROOT   TRUE

Definition at line 52 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ DEFAULT_MAXFREQLOC

#define DEFAULT_MAXFREQLOC   FALSE

Definition at line 53 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ DEFAULT_MAXNBESTSOLS

#define DEFAULT_MAXNBESTSOLS   25

Definition at line 54 of file heur_local.c.

Referenced by SCIPStpIncludeHeurLocal().

◆ DEFAULT_NBESTSOLS

#define DEFAULT_NBESTSOLS   10

Definition at line 55 of file heur_local.c.

Referenced by SCIP_DECL_HEURINITSOL().

◆ DEFAULT_MINNBESTSOLS

#define DEFAULT_MINNBESTSOLS   6

Definition at line 56 of file heur_local.c.

Referenced by SCIP_DECL_HEUREXEC().

◆ LOCAL_MAXRESTARTS

#define LOCAL_MAXRESTARTS   5

Definition at line 57 of file heur_local.c.

◆ GREEDY_MAXRESTARTS

#define GREEDY_MAXRESTARTS   3

Max number of restarts for greedy PC/MW heuristic if improving solution has been found.

Definition at line 59 of file heur_local.c.

Referenced by SCIPStpHeurLocalExtendPcMw().

◆ GREEDY_EXTENSIONS_MW

#define GREEDY_EXTENSIONS_MW   6

Number of extensions for greedy MW heuristic. MUST BE HIGHER THAN GREEDY_EXTENSIONS

Definition at line 60 of file heur_local.c.

Referenced by SCIPStpHeurLocalExtendPcMw().

◆ GREEDY_EXTENSIONS

#define GREEDY_EXTENSIONS   5

Number of extensions for greedy PC heuristic.

Definition at line 61 of file heur_local.c.

Referenced by SCIPStpHeurLocalExtendPcMw().

Function Documentation

◆ dfsorder()

static void dfsorder ( const GRAPH graph,
const int *  edges,
const int *  node,
int *  counter,
int *  dfst 
)
static

recursive methode for a DFS ordering of graph 'g'

Definition at line 86 of file heur_local.c.

References GRAPH::head, GRAPH::oeat, and GRAPH::outbeg.

Referenced by SCIPStpHeurLocalRun().

◆ lca()

static SCIP_RETCODE lca ( SCIP scip,
const GRAPH graph,
int  u,
UF uf,
STP_Bool nodesmark,
int *  steineredges,
IDX **  lcalists,
PHNODE **  boundpaths,
int *  heapsize,
int *  vbase 
)
static

computes lowest common ancestors for all pairs {vbase(v), vbase(u)} such that {u,w} is a boundary edge, first call should be with u := root

Definition at line 113 of file heur_local.c.

References EAT_LAST, FALSE, GRAPH::head, Int_List_Node::index, GRAPH::oeat, GRAPH::outbeg, UnionFind_Structure::parent, Int_List_Node::parent, SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemory, SCIPfreeBufferArray, SCIPpairheapBuffarr(), SCIPStpunionfindFind(), SCIPStpunionfindUnion(), and TRUE.

Referenced by SCIPStpHeurLocalRun().

◆ nodeIsCrucial()

static STP_Bool nodeIsCrucial ( const GRAPH graph,
int *  steineredges,
int  node 
)
static

checks whether node is crucial, i.e. a terminal or a vertex with degree at least 3 (w.r.t. the steinertree)

Definition at line 175 of file heur_local.c.

References FALSE, flipedge, NULL, GRAPH::oeat, GRAPH::outbeg, GRAPH::term, and TRUE.

Referenced by SCIPStpHeurLocalRun().

◆ SCIPStpHeurLocalRun()

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

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

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 1692 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().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyLocal  )
static

copy method for primal heuristic plugins (called when SCIP copies plugins)

Definition at line 1963 of file heur_local.c.

References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPStpIncludeHeurLocal().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeLocal  )
static

destructor of primal heuristic to free user data (called when SCIP is exiting)

Definition at line 1977 of file heur_local.c.

References HEUR_NAME, NULL, SCIP_OKAY, SCIPfreeMemory, SCIPheurGetData(), SCIPheurGetName(), and SCIPheurSetData().

◆ SCIP_DECL_HEURINITSOL()

static SCIP_DECL_HEURINITSOL ( heurInitsolLocal  )
static

solving process initialization method of primal heuristic (called when branch and bound process is about to begin)

Definition at line 1996 of file heur_local.c.

References DEFAULT_NBESTSOLS, HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocMemoryArray, SCIPheurGetData(), and SCIPheurGetName().

◆ SCIP_DECL_HEUREXITSOL()

static SCIP_DECL_HEUREXITSOL ( heurExitsolLocal  )
static

solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)

Definition at line 2021 of file heur_local.c.

References HEUR_NAME, NULL, SCIP_OKAY, SCIPfreeMemoryArray, SCIPheurGetData(), and SCIPheurGetName().

◆ SCIP_DECL_HEUREXEC()

◆ SCIPStpIncludeHeurLocal()