Scippy

SCIP

Solving Constraint Integer Programs

Functions
heur_twoopt.h File Reference
Primal Heuristics

Detailed Description

Primal heuristic to improve incumbent solution by flipping pairs of variables.

Author
Timo Berthold
Gregor Hendel

The Twoopt heuristic attempts to improve a feasible MIP solution by altering the solution values of pairs of variables. Only variables which share a pre-defined ratio of LP rows are considered as pairs. Each step of the heuristic consists of improving the objective value by shifting one variable, and then compensating the resulting infeasibilities by shifting a second variable, without completely losing the objective improvement. Similarly to Oneopt (see heur_oneopt.h), pairs are processed in non-decreasing order of their impact on the objective.

Definition in file heur_twoopt.h.

#include "scip/scip.h"

Go to the source code of this file.

Functions

SCIP_RETCODE SCIPincludeHeurTwoopt (SCIP *scip)
 

Function Documentation

SCIP_RETCODE SCIPincludeHeurTwoopt ( SCIP *  scip)

creates the twoopt primal heuristic and includes it in SCIP

Parameters
scipSCIP data structure

Definition at line 1740 of file heur_twoopt.c.

References DEFAULT_INTOPT, DEFAULT_MATCHINGRATE, DEFAULT_MAXNSLAVES, DEFAULT_WAITINGNODES, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_OKAY, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurExit(), SCIPsetHeurExitsol(), SCIPsetHeurFree(), SCIPsetHeurInit(), SCIPsetHeurInitsol(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), SCIP_DECL_HEUREXEC(), and SCIPincludeDefaultPlugins().