SCIP
Solving Constraint Integer Programs
Solving Constraint Integer Programs
LNS heuristic using a clique partition to restrict the search neighborhood.
clique primal heuristic
More details about the heuristic can be found in
Structure-Based Primal Heuristics for Mixed Integer Programming
Gerald Gamrath, Timo Berthold, Stefan Heinz, and Michael Winkler
Optimization in the Real World, Volume 13 of the series Mathematics for Industry, pp 37-53
Preliminary version available as ZIB-Report 15-26.
Definition in file heur_clique.c.
#include <assert.h>#include <string.h>#include "scip/scip.h"#include "scip/pub_implics.h"#include "scip/heur_clique.h"#include "scip/heur_locks.h"#include "scip/cons_logicor.h"#include "scip/pub_misc.h"Go to the source code of this file.
Macros | |
| #define | HEUR_NAME "clique" |
| #define | HEUR_DESC "LNS heuristic using a clique partition to restrict the search neighborhood" |
| #define | HEUR_DISPCHAR 'Q' |
| #define | HEUR_PRIORITY 5000 |
| #define | HEUR_FREQ 0 |
| #define | HEUR_FREQOFS 0 |
| #define | HEUR_MAXDEPTH -1 |
| #define | HEUR_TIMING SCIP_HEURTIMING_BEFORENODE |
| #define | HEUR_USESSUBSCIP TRUE |
| #define | DEFAULT_MAXNODES 5000LL |
| #define | DEFAULT_MININTFIXINGRATE 0.65 |
| #define | DEFAULT_MINMIPFIXINGRATE 0.65 |
| #define | DEFAULT_MINIMPROVE 0.01 |
| #define | DEFAULT_MINNODES 500LL |
| #define | DEFAULT_NODESOFS 500LL |
| #define | DEFAULT_NODESQUOT 0.1 |
| #define | DEFAULT_MAXPROPROUNDS 2 |
| #define | DEFAULT_MAXBACKTRACKS 10 |
| #define | DEFAULT_COPYCUTS TRUE |
| #define | DEFAULT_USELOCKFIXINGS FALSE |
Functions | |
| static | SCIP_DECL_SORTINDCOMP (compCliquesSize) |
| static int | getCliqueUnfixedVars (SCIP_CLIQUE *clique) |
| static SCIP_RETCODE | applyCliqueFixings (SCIP *scip, SCIP_HEURDATA *heurdata, SCIP_VAR **onefixvars, SCIP_Shortbool *onefixvals, int *nonefixvars, SCIP_Bool *cutoff) |
| static SCIP_RETCODE | createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_SOL *newsol, SCIP_SOL *subsol, SCIP_Bool *success) |
| static | SCIP_DECL_HEURCOPY (heurCopyClique) |
| static | SCIP_DECL_HEURFREE (heurFreeClique) |
| static | SCIP_DECL_HEURINIT (heurInitClique) |
| static | SCIP_DECL_HEUREXEC (heurExecClique) |
| SCIP_RETCODE | SCIPincludeHeurClique (SCIP *scip) |
| #define HEUR_NAME "clique" |
Definition at line 46 of file heur_clique.c.
Referenced by createNewSol().
| #define HEUR_DESC "LNS heuristic using a clique partition to restrict the search neighborhood" |
Definition at line 47 of file heur_clique.c.
| #define HEUR_DISPCHAR 'Q' |
Definition at line 48 of file heur_clique.c.
| #define HEUR_PRIORITY 5000 |
Definition at line 49 of file heur_clique.c.
| #define HEUR_FREQ 0 |
Definition at line 50 of file heur_clique.c.
| #define HEUR_FREQOFS 0 |
Definition at line 51 of file heur_clique.c.
| #define HEUR_MAXDEPTH -1 |
Definition at line 52 of file heur_clique.c.
| #define HEUR_TIMING SCIP_HEURTIMING_BEFORENODE |
Definition at line 53 of file heur_clique.c.
| #define HEUR_USESSUBSCIP TRUE |
does the heuristic use a secondary SCIP instance?
Definition at line 54 of file heur_clique.c.
| #define DEFAULT_MAXNODES 5000LL |
maximum number of nodes to regard in the subproblem
Definition at line 56 of file heur_clique.c.
| #define DEFAULT_MININTFIXINGRATE 0.65 |
minimum percentage of integer variables that have to be fixed
Definition at line 57 of file heur_clique.c.
| #define DEFAULT_MINMIPFIXINGRATE 0.65 |
minimum percentage of variables that have to be fixed within sub-SCIP (integer and continuous)
Definition at line 58 of file heur_clique.c.
| #define DEFAULT_MINIMPROVE 0.01 |
factor by which clique heuristic should at least improve the incumbent
Definition at line 61 of file heur_clique.c.
| #define DEFAULT_MINNODES 500LL |
minimum number of nodes to regard in the subproblem
Definition at line 66 of file heur_clique.c.
| #define DEFAULT_NODESOFS 500LL |
number of nodes added to the contingent of the total nodes
Definition at line 67 of file heur_clique.c.
| #define DEFAULT_NODESQUOT 0.1 |
subproblem nodes in relation to nodes of the original problem
Definition at line 68 of file heur_clique.c.
| #define DEFAULT_MAXPROPROUNDS 2 |
maximum number of propagation rounds during probing
Definition at line 69 of file heur_clique.c.
| #define DEFAULT_MAXBACKTRACKS 10 |
maximum number of backtracks during the fixing process
Definition at line 70 of file heur_clique.c.
| #define DEFAULT_COPYCUTS TRUE |
should all active cuts from the cutpool of the original scip be copied to constraints of the subscip
Definition at line 71 of file heur_clique.c.
| #define DEFAULT_USELOCKFIXINGS FALSE |
should more variables be fixed based on variable locks if the fixing rate was not reached?
Definition at line 76 of file heur_clique.c.
|
static |
comparison method for sorting cliques by their size
Definition at line 115 of file heur_clique.c.
|
static |
Definition at line 123 of file heur_clique.c.
Referenced by applyCliqueFixings().
|
static |
apply clique fixing using probing
| scip | original SCIP data structure |
| heurdata | structure containing heurdata |
| onefixvars | array to store all variables which are fixed to one in the cliques |
| onefixvals | array to store the values of all variables fixed to one in the cliques |
| nonefixvars | pointer to store the number of variables fixed to one |
| cutoff | pointer to store whether the propagation stopped with infeasibility |
Definition at line 150 of file heur_clique.c.
References createNewSol(), FALSE, getCliqueUnfixedVars(), SCIP_Bool, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_MAXTREEDEPTH, SCIP_OKAY, SCIP_Real, SCIPaddConsNode(), SCIPallocBufferArray, SCIPallocClearBufferArray, SCIPbacktrackProbing(), SCIPcliqueGetNVars(), SCIPcliqueGetValues(), SCIPcliqueGetVars(), SCIPcreateConsLogicor(), SCIPdebugMessage, SCIPdebugMsg, SCIPdebugPrintCons, SCIPfixVarProbing(), SCIPfreeBufferArray, SCIPgetCliques(), SCIPgetDepth(), SCIPgetFocusNode(), SCIPgetNBinVars(), SCIPgetNCliques(), SCIPgetNegatedVar(), SCIPgetNNodes(), SCIPgetProbingDepth(), SCIPinfinity(), SCIPisStopped(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIPreleaseCons(), SCIPsnprintf(), SCIPsort(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetUbLocal(), and TRUE.
|
static |
creates a new solution for the original problem by copying the solution of the subproblem
| scip | original SCIP data structure |
| subscip | SCIP structure of the subproblem |
| subvars | the variables of the subproblem |
| newsol | working solution |
| subsol | solution of the subproblem |
| success | used to store whether new solution was found or not |
Definition at line 491 of file heur_clique.c.
References FALSE, HEUR_NAME, SCIP_CALL, SCIP_DECL_HEURCOPY(), SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPheurGetName(), SCIPsetSolVals(), SCIPtrySol(), and TRUE.
Referenced by applyCliqueFixings().
|
static |
copy method for primal heuristic plugins (called when SCIP copies plugins)
Definition at line 539 of file heur_clique.c.
Referenced by createNewSol().
|
static |
destructor of primal heuristic to free user data (called when SCIP is exiting)
Definition at line 553 of file heur_clique.c.
|
static |
initialization method of primal heuristic (called after problem was transformed)
Definition at line 574 of file heur_clique.c.
|
static |
execution method of primal heuristic
Definition at line 593 of file heur_clique.c.