# SCIP

Solving Constraint Integer Programs

sepa_cgmip.c File Reference

## Detailed Description

Chvatal-Gomory cuts computed via a sub-MIP.

Separate Chvátal-Gomory cuts using a sub-MIP. The approach is based on the following papers.

M. Fischetti and A. Lodi
Optimizing over the first Chvátal closure,
in: M. Jünger and V. Kaibel (eds.) Integer Programming and Combinatorial Optimization IPCO 2005,
LNCS 3509, pp. 12-22. Springer, Berlin Heidelberg New York (2005)

M. Fischetti and A. Lodi
Optimizing over the first Chvátal closure,
Mathematical Programming 110, 3-20 (2007)

P. Bonami, G. Cornuéjols, S. Dash, M. Fischetti, and A. Lodi
Projected Chvátal-Gomory cuts for mixed integer linear programs,
Mathematical Programming 113, No. 2 (2008)

There are several possibilities to generate the final cut:

• The CMIR-routines of SCIP can be used (if usecmir is true). One can determine which bound is used in the rounding operation (if cmirownbounds is true) or let SCIP choose the best. This version is generally numerically the most stable.
• If usestrongcg is true, we try to generate Strong-CG cuts (as done in sepa_strongcg.c).
• One can directly generate the CG-cut as computed (if usecmir and usestrongcg are false). The cut is not taken from the solution of the MIP, but is recomputed, and some care (but not as much as in the first version) has been taken to create a valid cut.

The computation time of the separation MIP is limited as follows:

• There is a node limit (parameters minnodelimit and maxnodelimit).
• There is a time limit (parameter timelimit).
• If paramter earlyterm is true, the separation is run until the first cut that is violated is found. (Note that these cuts are not necessarily added to the LP, because here also the norm of the cuts are taken into account - which cannot easily be included into the separation subscip.) Then the solution process is continued for a certain number of nodes.
Warning
This separator should be used carefully - it may require a long separation time.

Definition in file sepa_cgmip.c.

#include "blockmemshell/memory.h"
#include "scip/cons_linear.h"
#include "scip/cuts.h"
#include "scip/pub_cons.h"
#include "scip/pub_lp.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_sepa.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_cut.h"
#include "scip/scip_general.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_randnumgen.h"
#include "scip/scip_sepa.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include "scip/scip_timing.h"
#include "scip/scip_tree.h"
#include "scip/scip_var.h"
#include "scip/scipdefplugins.h"
#include "scip/sepa_cgmip.h"
#include <string.h>

Go to the source code of this file.

## Macros

#define SEPA_NAME   "cgmip"

#define SEPA_DESC   "Chvatal-Gomory cuts via MIPs separator"

#define SEPA_PRIORITY   -1000

#define SEPA_FREQ   -1

#define SEPA_MAXBOUNDDIST   0.0

#define SEPA_USESSUBSCIP   TRUE

#define SEPA_DELAY   FALSE

#define DEFAULT_MAXROUNDS   5

#define DEFAULT_MAXROUNDSROOT   50

#define DEFAULT_MAXDEPTH   -1

#define DEFAULT_DECISIONTREE   FALSE

#define DEFAULT_TIMELIMIT   1e20

#define DEFAULT_MEMORYLIMIT   1e20

#define DEFAULT_CUTCOEFBND   1000.0

#define DEFAULT_MINNODELIMIT   500LL

#define DEFAULT_MAXNODELIMIT   5000LL

#define DEFAULT_ONLYACTIVEROWS   FALSE

#define DEFAULT_MAXROWAGE   -1

#define DEFAULT_ONLYRANKONE   FALSE

#define DEFAULT_ONLYINTVARS   FALSE

#define DEFAULT_CONTCONVERT   FALSE

#define DEFAULT_CONTCONVFRAC   0.1

#define DEFAULT_CONTCONVMIN   100

#define DEFAULT_INTCONVERT   FALSE

#define DEFAULT_INTCONVFRAC   0.1

#define DEFAULT_INTCONVMIN   100

#define DEFAULT_SKIPMULTBOUNDS   TRUE

#define DEFAULT_OBJLONE   FALSE

#define DEFAULT_OBJWEIGHT   1e-03

#define DEFAULT_OBJWEIGHTSIZE   TRUE

#define DEFAULT_DYNAMICCUTS   TRUE

#define DEFAULT_USECMIR   TRUE

#define DEFAULT_USESTRONGCG   FALSE

#define DEFAULT_CMIROWNBOUNDS   FALSE

#define DEFAULT_USECUTPOOL   TRUE

#define DEFAULT_PRIMALSEPARATION   TRUE

#define DEFAULT_EARLYTERM   TRUE

#define DEFAULT_ADDVIOLATIONCONS   FALSE

#define DEFAULT_ADDVIOLCONSHDLR   FALSE

#define DEFAULT_CONSHDLRUSENORM   TRUE

#define DEFAULT_USEOBJUB   FALSE

#define DEFAULT_USEOBJLB   FALSE

#define DEFAULT_SUBSCIPFAST   TRUE

#define DEFAULT_OUTPUT   FALSE

#define DEFAULT_RANDSEED   101

#define NROWSTOOSMALL   5

#define NCOLSTOOSMALL   5

#define EPSILONVALUE   1e-03

#define BETAEPSILONVALUE   1e-02

#define STALLNODELIMIT   1000LL

#define CONSHDLRFULLNORM   FALSE

#define MINEFFICACY   0.05

#define MAXNSOLS   1000

#define OBJWEIGHTRANGE   0.01

#define BOUNDSWITCH   0.9999

#define USEVBDS   TRUE

#define POSTPROCESS   TRUE

#define MINFRAC   0.0009 /* to allow a deviation of the same size as EPSILONVALUE */

#define MAXFRAC   0.9991 /* to allow a deviation of the same size as EPSILONVALUE */

#define FIXINTEGRALRHS   FALSE

#define MAKECONTINTEGRAL   FALSE

#define MAXWEIGHTRANGE   1e+05

#define MAXAGGRLEN(nvars)   nvars

#define CONSHDLR_NAME   "violatedCuts"

#define CONSHDLR_DESC   "only allow solutions corresponding to violated cuts"

## Typedefs

typedef enum CGMIP_ColType CGMIP_COLTYPE

typedef struct CGMIP_MIPData CGMIP_MIPDATA

## Enumerations

enum  CGMIP_ColType {
colPresent = 0,
colContinuous = 1,
colConverted = 2,
colAtUb = 3,
colAtLb = 4
}

## Functions

static SCIP_RETCODE computeCut (SCIP *scip, SCIP_SEPA *sepa, CGMIP_MIPDATA *mipdata, SCIP_SEPADATA *sepadata, SCIP_SOL *sol, SCIP_Real *cutcoefs, SCIP_Real *cutrhs, SCIP_Bool *localrowsused, SCIP_Bool *localboundsused, int *cutrank, SCIP_Bool *success)

static SCIP_RETCODE solCutIsViolated (SCIP *scip, CGMIP_MIPDATA *mipdata, SCIP_SOL *sol, SCIP_Bool *violated)

static SCIP_DECL_CONSFREE (consFreeViolatedCuts)

static SCIP_DECL_CONSENFOLP (consEnfolpViolatedCuts)

static SCIP_DECL_CONSENFOPS (consEnfopsViolatedCuts)

static SCIP_DECL_CONSCHECK (consCheckViolatedCuts)

static SCIP_DECL_CONSLOCK (consLockViolatedCuts)

static SCIP_RETCODE SCIPincludeConshdlrViolatedCut (SCIP *scip, CGMIP_MIPDATA *mipdata)

static SCIP_RETCODE storeCutInArrays (SCIP *scip, int nvars, SCIP_Real *cutcoefs, SCIP_Real *varsolvals, char normtype, int *cutinds, SCIP_Real *cutvals, int *cutlen, SCIP_Real *cutact, SCIP_Real *cutnorm)

static SCIP_RETCODE transformColumn (SCIP *scip, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_COL *col, SCIP_Real offset, SCIP_Real sigma, SCIP_Real *lhs, SCIP_Real *rhs, SCIP_Real *lb, SCIP_Real *ub, SCIP_Real *primsol)

static SCIP_Real computeObjWeightSize (int rowsize, int minrowsize, int maxrowsize)

static SCIP_RETCODE createSubscip (SCIP *scip, SCIP_SEPA *sepa, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata)

static SCIP_RETCODE subscipSetParams (SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata)

static SCIP_RETCODE solveSubscip (SCIP *scip, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_Bool *success)

static SCIP_RETCODE createCGCutDirect (SCIP *scip, SCIP_SEPA *sepa, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_SOL *sol, SCIP_Real *cutcoefs, int *cutinds, SCIP_Real *cutvals, SCIP_Real *varsolvals, SCIP_Real *weights, int *nprevrows, SCIP_ROW **prevrows, SCIP_Bool *cutoff, unsigned int *ngen)

static SCIP_RETCODE createCGCutCMIR (SCIP *scip, SCIP_SEPA *sepa, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_SOL *sol, SCIP_AGGRROW *aggrrow, SCIP_Real *cutcoefs, int *cutinds, SCIP_Real *cutvals, SCIP_Real *varsolvals, SCIP_Real *weights, int *boundsfortrans, SCIP_BOUNDTYPE *boundtypesfortrans, int *nprevrows, SCIP_ROW **prevrows, SCIP_Bool *cutoff, unsigned int *ngen)

static SCIP_RETCODE createCGCutStrongCG (SCIP *scip, SCIP_SEPA *sepa, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_SOL *sol, SCIP_AGGRROW *aggrrow, SCIP_Real *cutcoefs, int *cutinds, SCIP_Real *cutvals, SCIP_Real *varsolvals, SCIP_Real *weights, int *nprevrows, SCIP_ROW **prevrows, SCIP_Bool *cutoff, unsigned int *ngen)

static SCIP_RETCODE createCGCuts (SCIP *scip, SCIP_SEPA *sepa, SCIP_SEPADATA *sepadata, CGMIP_MIPDATA *mipdata, SCIP_Bool *cutoff, unsigned int *ngen)

static SCIP_RETCODE freeSubscip (SCIP *scip, SCIP_SEPA *sepa, CGMIP_MIPDATA *mipdata)

static SCIP_DECL_SEPAINIT (sepaInitCGMIP)

static SCIP_DECL_SEPAEXIT (sepaExitCGMIP)

static SCIP_DECL_SEPACOPY (sepaCopyCGMIP)

static SCIP_DECL_SEPAFREE (sepaFreeCGMIP)

static SCIP_DECL_SEPAEXECLP (sepaExeclpCGMIP)

SCIP_RETCODE SCIPincludeSepaCGMIP (SCIP *scip)

## ◆ SEPA_NAME

 #define SEPA_NAME   "cgmip"

## ◆ SEPA_DESC

 #define SEPA_DESC   "Chvatal-Gomory cuts via MIPs separator"

Definition at line 97 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ SEPA_PRIORITY

 #define SEPA_PRIORITY   -1000

Definition at line 98 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ SEPA_FREQ

 #define SEPA_FREQ   -1

Definition at line 99 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ SEPA_MAXBOUNDDIST

 #define SEPA_MAXBOUNDDIST   0.0

Definition at line 100 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ SEPA_USESSUBSCIP

 #define SEPA_USESSUBSCIP   TRUE

does the separator use a secondary SCIP instance?

Definition at line 101 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ SEPA_DELAY

 #define SEPA_DELAY   FALSE

should separation method be delayed, if other separators found cuts?

Definition at line 102 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MAXROUNDS

 #define DEFAULT_MAXROUNDS   5

maximal number of separation rounds per node (-1: unlimited)

Definition at line 104 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MAXROUNDSROOT

 #define DEFAULT_MAXROUNDSROOT   50

maximal number of separation rounds in the root node (-1: unlimited)

Definition at line 105 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MAXDEPTH

 #define DEFAULT_MAXDEPTH   -1

maximal depth at which the separator is applied

Definition at line 106 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_DECISIONTREE

 #define DEFAULT_DECISIONTREE   FALSE

Use decision tree to turn separation on/off?

Definition at line 107 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_TIMELIMIT

 #define DEFAULT_TIMELIMIT   1e20

time limit for sub-MIP (set to infinity in order to be deterministic)

Definition at line 108 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MEMORYLIMIT

 #define DEFAULT_MEMORYLIMIT   1e20

memory limit for sub-MIP

Definition at line 109 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CUTCOEFBND

 #define DEFAULT_CUTCOEFBND   1000.0

bounds on the values of the coefficients in the CG-cut

Definition at line 110 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MINNODELIMIT

 #define DEFAULT_MINNODELIMIT   500LL

minimum number of nodes considered for sub-MIP (-1: unlimited)

Definition at line 111 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MAXNODELIMIT

 #define DEFAULT_MAXNODELIMIT   5000LL

maximum number of nodes considered for sub-MIP (-1: unlimited)

Definition at line 112 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_ONLYACTIVEROWS

 #define DEFAULT_ONLYACTIVEROWS   FALSE

Use only active rows to generate cuts?

Definition at line 113 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_MAXROWAGE

 #define DEFAULT_MAXROWAGE   -1

maximal age of rows to consider if onlyactiverows is false

Definition at line 114 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_ONLYRANKONE

 #define DEFAULT_ONLYRANKONE   FALSE

Separate rank 1 inequalities w.r.t. CG-MIP separator?

Definition at line 115 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_ONLYINTVARS

 #define DEFAULT_ONLYINTVARS   FALSE

Generate cuts for problems with only integer variables?

Definition at line 116 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CONTCONVERT

 #define DEFAULT_CONTCONVERT   FALSE

Convert some integral variables to be continuous to reduce the size of the sub-MIP?

Definition at line 117 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CONTCONVFRAC

 #define DEFAULT_CONTCONVFRAC   0.1

fraction of integral variables converted to be continuous (if contconvert)

Definition at line 118 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CONTCONVMIN

 #define DEFAULT_CONTCONVMIN   100

minimum number of integral variables before some are converted to be continuous

Definition at line 119 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_INTCONVERT

 #define DEFAULT_INTCONVERT   FALSE

Convert some integral variables attaining fractional values to have integral value?

Definition at line 120 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_INTCONVFRAC

 #define DEFAULT_INTCONVFRAC   0.1

fraction of fractional integral variables converted to have integral value (if intconvert)

Definition at line 121 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_INTCONVMIN

 #define DEFAULT_INTCONVMIN   100

minimum number of integral variables before some are converted to have integral value

Definition at line 122 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_SKIPMULTBOUNDS

 #define DEFAULT_SKIPMULTBOUNDS   TRUE

Skip the upper bounds on the multipliers in the sub-MIP?

Definition at line 123 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_OBJLONE

 #define DEFAULT_OBJLONE   FALSE

Should the objective of the sub-MIP only minimize the l1-norm of the multipliers?

Definition at line 124 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_OBJWEIGHT

 #define DEFAULT_OBJWEIGHT   1e-03

objective weight for artificial variables

Definition at line 125 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_OBJWEIGHTSIZE

 #define DEFAULT_OBJWEIGHTSIZE   TRUE

Weight each row by its size?

Definition at line 126 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_DYNAMICCUTS

 #define DEFAULT_DYNAMICCUTS   TRUE

Should generated cuts be removed from the LP if they are no longer tight?

Definition at line 127 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_USECMIR

 #define DEFAULT_USECMIR   TRUE

Use CMIR-generator (otherwise add cut directly)?

Definition at line 128 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_USESTRONGCG

 #define DEFAULT_USESTRONGCG   FALSE

Use strong CG-function to strengthen cut?

Definition at line 129 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CMIROWNBOUNDS

 #define DEFAULT_CMIROWNBOUNDS   FALSE

Tell CMIR-generator which bounds to used in rounding?

Definition at line 130 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_USECUTPOOL

 #define DEFAULT_USECUTPOOL   TRUE

Use cutpool to store CG-cuts even if the are not efficient?

Definition at line 131 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_PRIMALSEPARATION

 #define DEFAULT_PRIMALSEPARATION   TRUE

Only separate cuts that are tight for the best feasible solution?

Definition at line 132 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_EARLYTERM

 #define DEFAULT_EARLYTERM   TRUE

Terminate separation if a violated (but possibly sub-optimal) cut has been found?

Definition at line 133 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_ADDVIOLATIONCONS

 #define DEFAULT_ADDVIOLATIONCONS   FALSE

Add constraint to subscip that only allows violated cuts (otherwise add obj. limit)?

Definition at line 134 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_ADDVIOLCONSHDLR

 #define DEFAULT_ADDVIOLCONSHDLR   FALSE

Add constraint handler to filter out violated cuts?

Definition at line 135 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_CONSHDLRUSENORM

 #define DEFAULT_CONSHDLRUSENORM   TRUE

Should the violation constraint handler use the norm of a cut to check for feasibility?

Definition at line 136 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_USEOBJUB

 #define DEFAULT_USEOBJUB   FALSE

Use upper bound on objective function (via primal solution)?

Definition at line 137 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_USEOBJLB

 #define DEFAULT_USEOBJLB   FALSE

Use lower bound on objective function (via lower bound)?

Definition at line 138 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_SUBSCIPFAST

 #define DEFAULT_SUBSCIPFAST   TRUE

Should the settings for the sub-MIP be optimized for speed?

Definition at line 139 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_OUTPUT

 #define DEFAULT_OUTPUT   FALSE

Should information about the sub-MIP and cuts be displayed?

Definition at line 140 of file sepa_cgmip.c.

Referenced by SCIPincludeSepaCGMIP().

## ◆ DEFAULT_RANDSEED

 #define DEFAULT_RANDSEED   101

start random seed for random number generation

Definition at line 141 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAINIT().

## ◆ NROWSTOOSMALL

 #define NROWSTOOSMALL   5

only separate if the number of rows is larger than this number

Definition at line 143 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ NCOLSTOOSMALL

 #define NCOLSTOOSMALL   5

only separate if the number of columns is larger than this number

Definition at line 144 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ EPSILONVALUE

 #define EPSILONVALUE   1e-03

epsilon value needed to model strict-inequalities

Definition at line 146 of file sepa_cgmip.c.

Referenced by createSubscip().

## ◆ BETAEPSILONVALUE

 #define BETAEPSILONVALUE   1e-02

epsilon value for fracbeta - is larger than EPSILONVALUE for numerical stability

Definition at line 147 of file sepa_cgmip.c.

Referenced by createSubscip().

## ◆ STALLNODELIMIT

 #define STALLNODELIMIT   1000LL

number of stalling nodes if earlyterm is true

Definition at line 148 of file sepa_cgmip.c.

Referenced by solveSubscip().

## ◆ CONSHDLRFULLNORM

 #define CONSHDLRFULLNORM   FALSE

compute real cut and compute norm for this (if addviolconshdlr and conshdlrusenorm are true)

Definition at line 149 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ MINEFFICACY

 #define MINEFFICACY   0.05

minimum efficacy of a cut - compare set.c

Definition at line 150 of file sepa_cgmip.c.

Referenced by createSubscip(), and subscipSetParams().

## ◆ MAXNSOLS

 #define MAXNSOLS   1000

maximal number of solutions stored in sub-SCIP

Definition at line 151 of file sepa_cgmip.c.

Referenced by subscipSetParams().

## ◆ OBJWEIGHTRANGE

 #define OBJWEIGHTRANGE   0.01

maximal range of scaling of objective w.r.t. size of rows

Definition at line 152 of file sepa_cgmip.c.

Referenced by computeObjWeightSize().

## ◆ BOUNDSWITCH

 #define BOUNDSWITCH   0.9999

Definition at line 155 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ USEVBDS

 #define USEVBDS   TRUE

Definition at line 156 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ POSTPROCESS

 #define POSTPROCESS   TRUE

Definition at line 157 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ MINFRAC

 #define MINFRAC   0.0009 /* to allow a deviation of the same size as EPSILONVALUE */

Definition at line 158 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ MAXFRAC

 #define MAXFRAC   0.9991 /* to allow a deviation of the same size as EPSILONVALUE */

Definition at line 159 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ FIXINTEGRALRHS

 #define FIXINTEGRALRHS   FALSE

Definition at line 160 of file sepa_cgmip.c.

Referenced by createCGCutCMIR().

## ◆ MAKECONTINTEGRAL

 #define MAKECONTINTEGRAL   FALSE

Definition at line 161 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ MAXWEIGHTRANGE

 #define MAXWEIGHTRANGE   1e+05

maximal valid range max(|weights|)/min(|weights|) of row weights

Definition at line 162 of file sepa_cgmip.c.

Referenced by computeCut().

## ◆ MAXAGGRLEN

 #define MAXAGGRLEN ( nvars ) nvars

currently very large to allow any generation; an alternative would be (0.1*(nvars)+1000)

Definition at line 164 of file sepa_cgmip.c.

Referenced by createCGCutCMIR(), and createCGCutStrongCG().

## ◆ CONSHDLR_NAME

 #define CONSHDLR_NAME   "violatedCuts"

Definition at line 263 of file sepa_cgmip.c.

Referenced by SCIPincludeConshdlrViolatedCut().

## ◆ CONSHDLR_DESC

 #define CONSHDLR_DESC   "only allow solutions corresponding to violated cuts"

Definition at line 264 of file sepa_cgmip.c.

Referenced by SCIPincludeConshdlrViolatedCut().

## ◆ CGMIP_COLTYPE

 typedef enum CGMIP_ColType CGMIP_COLTYPE

Definition at line 220 of file sepa_cgmip.c.

## ◆ CGMIP_MIPDATA

 typedef struct CGMIP_MIPData CGMIP_MIPDATA

Definition at line 255 of file sepa_cgmip.c.

## ◆ CGMIP_ColType

 enum CGMIP_ColType

what happens for columns in the LP

Enumerator
colPresent

column is present in the separating MIP

colContinuous

column corresponds to a continuous variable

colConverted

column is converted to be continuous

colAtUb

variable corresponding to column was at it's upper bound and was complemented

colAtLb

variable corresponding to column was at it's lower bound (possibly complemented)

Definition at line 212 of file sepa_cgmip.c.

## ◆ computeCut()

 static SCIP_RETCODE computeCut ( SCIP * scip, SCIP_SEPA * sepa, CGMIP_MIPDATA * mipdata, SCIP_SEPADATA * sepadata, SCIP_SOL * sol, SCIP_Real * cutcoefs, SCIP_Real * cutrhs, SCIP_Bool * localrowsused, SCIP_Bool * localboundsused, int * cutrank, SCIP_Bool * success )
static

Computes cut from the given multipliers

When computing the cut, we take the fractional part of the multipliers. This is known to produce stronger cuts in the pure integer case, since the cut is the sum of the one using fractional parts and integer multiples of the original constraints. However, if there are continuous variables, the resulting cut might not be valid. This is checked and returned.

Moreover, the cut computed here in general will not be the same as the one computed with the sub-MIP, because of numerical differences. Here, we only combine rows whose corresponding multiplier is positive w.r.t. the feasibility tolerance. In the sub-MIP, however, the rows are combined in any case. This makes a difference, if the coefficients in the matrix are large and hence yield a value that is larger than the tolerance.

Because of the transformations we have the following:

If variable $$x_j$$ was complemented, we have $$x'_j = u_j - x_j$$. If in the transformed system the lower bound is used, its corresponding multiplier is $$y^T A'_j - \lfloor y^T A'_j \rfloor$$, which corresponds to

$y^T A'_j - \lfloor y^T A'_j \rfloor = - y^T A_j - \lfloor - y^T A_j \rfloor = - y^T A_j + \lceil y^T A_j \rceil$

in the original system.

If such a variable was at its upper bound before the transformation, it is at its lower bound afterwards. Hence, its contribution to the cut is 0.

Note that if the original LP-solution does not satisfy some of the rows with equality the violation of the cut might be smaller than what is computed with the reduced sub-MIP.

Furthermore, note that if continuous variables have been shifted, the computed violated may be different as well, because the necessary changes in the lhs/rhs are not used here anymore.

Parameters
 scip original scip sepa separator mipdata data for sub-MIP sepadata separator data sol current solution for sub-MIP cutcoefs coefficients of the cut cutrhs rhs of the cut localrowsused pointer to store whether local rows were used in summation localboundsused pointer to store whether local bounds were used in summation cutrank pointer to store the cut rank success whether we produced a valid cut

Definition at line 2387 of file sepa_cgmip.c.

Referenced by createCGCutDirect(), and solCutIsViolated().

## ◆ solCutIsViolated()

 static SCIP_RETCODE solCutIsViolated ( SCIP * scip, CGMIP_MIPDATA * mipdata, SCIP_SOL * sol, SCIP_Bool * violated )
static

check whether cut corresponding to solution is violated

Parameters
 scip SCIP data structure mipdata data of separating sub-MIP sol solution to be checked violated pointer to store if the cut is violated

Definition at line 290 of file sepa_cgmip.c.

Referenced by SCIP_DECL_CONSCHECK(), and SCIP_DECL_CONSENFOLP().

## ◆ SCIP_DECL_CONSFREE()

 static SCIP_DECL_CONSFREE ( consFreeViolatedCuts )
static

destructor of constraint handler to free constraint handler data (called when SCIP is exiting)

Definition at line 483 of file sepa_cgmip.c.

References NULL, SCIP_OKAY, SCIPconshdlrGetData(), and SCIPfreeBlockMemory.

## ◆ SCIP_DECL_CONSENFOLP()

 static SCIP_DECL_CONSENFOLP ( consEnfolpViolatedCuts )
static

constraint enforcing method of constraint handler for LP solutions

Definition at line 500 of file sepa_cgmip.c.

## ◆ SCIP_DECL_CONSENFOPS()

 static SCIP_DECL_CONSENFOPS ( consEnfopsViolatedCuts )
static

constraint enforcing method of constraint handler for pseudo solutions

Definition at line 527 of file sepa_cgmip.c.

References NULL, SCIP_FEASIBLE, and SCIP_OKAY.

## ◆ SCIP_DECL_CONSCHECK()

 static SCIP_DECL_CONSCHECK ( consCheckViolatedCuts )
static

feasibility check method of constraint handler for integral solutions

Definition at line 541 of file sepa_cgmip.c.

## ◆ SCIP_DECL_CONSLOCK()

 static SCIP_DECL_CONSLOCK ( consLockViolatedCuts )
static

variable rounding lock method of constraint handler

Definition at line 567 of file sepa_cgmip.c.

References SCIP_OKAY.

## ◆ SCIPincludeConshdlrViolatedCut()

 static SCIP_RETCODE SCIPincludeConshdlrViolatedCut ( SCIP * scip, CGMIP_MIPDATA * mipdata )
static

creates the violated CG-cut constraint handler and includes it in SCIP

Parameters
 scip SCIP data structure mipdata data of separating sub-MIP

Definition at line 576 of file sepa_cgmip.c.

Referenced by createSubscip().

## ◆ storeCutInArrays()

 static SCIP_RETCODE storeCutInArrays ( SCIP * scip, int nvars, SCIP_Real * cutcoefs, SCIP_Real * varsolvals, char normtype, int * cutinds, SCIP_Real * cutvals, int * cutlen, SCIP_Real * cutact, SCIP_Real * cutnorm )
static

stores nonzero elements of dense coefficient vector as sparse vector and calculates activity and norm

copied from sepa_gomory.c

Parameters
 scip SCIP data structure nvars number of problem variables cutcoefs dense coefficient vector varsolvals dense variable LP solution vector normtype type of norm to use for efficacy norm calculation cutinds array to store variables of sparse cut vector cutvals array to store coefficients of sparse cut vector cutlen pointer to store number of nonzero entries in cut cutact pointer to store activity of cut cutnorm pointer to store norm of cut vector

Definition at line 612 of file sepa_cgmip.c.

References NULL, REALABS, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_Real, SCIPerrorMessage, SCIPisZero(), SQR, and SQRT.

Referenced by createCGCutDirect().

## ◆ transformColumn()

 static SCIP_RETCODE transformColumn ( SCIP * scip, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_COL * col, SCIP_Real offset, SCIP_Real sigma, SCIP_Real * lhs, SCIP_Real * rhs, SCIP_Real * lb, SCIP_Real * ub, SCIP_Real * primsol )
static

Compute lhs/rhs for transformed column

Consider a variable $$x_j$$ and some row of the original system:

$\gamma \leq a^T x \leq \delta, \quad \ell_j \leq x_j \leq u_j.$

We perform the transformation

$x_i' = \left\{ \begin{array}{ll} s + \frac{1}{\sigma}\, x_j & \mbox{if }i = j\\ x_i & \mbox{otherwise}, \end{array} \right.$

where $$s$$ is the offset value and $$\sigma$$ is a scaling factor. The new system is

$\gamma + \sigma\, a_j\,s \leq \sum_{i \neq j} a_i\, x_i' + \sigma a_j\, x_j' \leq \delta + \sigma\, a_j\, s$

with bounds

$\frac{1}{\sigma} \ell_j + s \leq x_j' \leq \frac{1}{\sigma} u_j + s, \qquad \mbox{ if }\sigma > 0$

and

$\frac{1}{\sigma} u_j + s \leq x_j' \leq \frac{1}{\sigma} \ell_j + s, \qquad \mbox{ if }\sigma < 0.$

This can be used as follows:

• If $$x_j \geq \ell_j$$ has a (nonzero) lower bound, one can use $$s = -\ell_j$$, $$\sigma = 1$$, and obtain $$\gamma - a_j\,\ell_j \leq a^T x' \leq \delta - a_j\,\ell_j$$, $$0 \leq x_j' \leq u_j - \ell_j$$.
• If $$x_j \leq u_j$$ has a (nonzero) upper bound, one can use $$s = u_j$$, $$\sigma = -1$$, and obtain $$\gamma - a_j\,u_j \leq \sum_{i \neq j} a_i\, x_i' - a_j\, x_j' \leq \delta - a_j\, u_j$$, $$0 \leq x_j' \leq u_j - \ell_j$$.
Parameters
 scip SCIP data structure sepadata separator data mipdata data for sub-MIP col column that should be complemented offset offset by which column should be shifted sigma scaling factor lhs array of lhs of rows rhs array rhs of rows lb pointer to lb of column ub pointer to ub of column primsol pointer to solution value

Definition at line 752 of file sepa_cgmip.c.

Referenced by createSubscip().

## ◆ computeObjWeightSize()

 static SCIP_Real computeObjWeightSize ( int rowsize, int minrowsize, int maxrowsize )
static

compute objective coefficient for rows that are weighted by size

The objective is computed by multiplying a default value by

$1 - (r_{\mbox{max}} - r) \frac{1 - a}{r_{\mbox{max}} - r_{\mbox{min}}},$

where $$r$$ is the size of the current row, $$a \in [0,1]$$ is a parameter, and $$r_{\mbox{max}}$$ and $$r_{\mbox{min}}$$ are the maximal and minimal size of a row, respectively.

Thus, if $$r = r_{\mbox{max}}$$, we get 1 and if $$r = r_{\mbox{min}}$$, we get $$a$$.

Parameters
 rowsize size of current row minrowsize maximal size of rows maxrowsize minimal size of rows

Definition at line 863 of file sepa_cgmip.c.

References a, OBJWEIGHTRANGE, and SCIP_Real.

Referenced by createSubscip().

## ◆ createSubscip()

 static SCIP_RETCODE createSubscip ( SCIP * scip, SCIP_SEPA * sepa, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata )
static

Creates a subscip representing the separating MIP.

Let the constraints of the original MIP be of the following form:

$\begin{array}{l@{\;}ll} a \leq A x + & C r & \leq b\\ \ell \leq x & & \leq u\\ c \leq & r & \leq d\\ x \in Z^n. \end{array}$

Here, some of the bounds may have value $$\infty$$ or $$-\infty$$. Written in $$\leq$$-form this becomes:

$\begin{array}{r@{\;}l} \tilde{A} x + \tilde{C} r & \leq \tilde{b}\\ -x & \leq -\ell\\ x & \leq u\\ -r & \leq -c\\ r & \leq d\\ x \in Z^n, \end{array}$

where we use

$\tilde{A} = \left[ \begin{array}{r} -A \\ A \end{array} \right], \quad \tilde{C} = \left[ \begin{array}{r} - C\\ C \end{array} \right] \qquad\mbox{ and }\qquad \tilde{b} = \left[ \begin{array}{r} -a\\ b \end{array} \right].$

For the moment we assume that $$c = 0$$, i.e., the lower bounds on the continuous variables are 0. To obtain a Chvátal-Gomory cut we have to find nonnegative multipliers $$y$$, $$\underline{z}$$, and $$\overline{z}$$ such that

$y^T \tilde{A} - \underline{z}^T + \overline{z}^T \in Z \qquad\mbox{ and }\qquad y^T \tilde{C} \geq 0.$

Note that we use zero multipliers for the bounds on the continuous variables $$r$$. Moreover, if some bounds are infinity, the corresponding multipliers are assumed to be 0. From these conditions, we obtain

$(y^T \tilde{A} - \underline{z}^T + \overline{z}^T)\, x + y^T \tilde{C} \, r \leq y^T \tilde{b} - \underline{z}^T \ell + \overline{z}^T u.$

Because $$r \geq 0$$, we can ignore the term $$y^T \tilde{C} \, r \geq 0$$ and obtain the following cut:

$(y^T \tilde{A} - \underline{z}^T + \overline{z}^T )\, x \leq \lfloor y^T \tilde{b} - \underline{z}^T \ell + \overline{z}^T u \rfloor.$

Assume that $$\ell = 0$$ for the meantime. Then the cut can be written as:

$\lfloor y^T \tilde{A} + \overline{z}^T \rfloor \, x \leq \lfloor y^T \tilde{b} + \overline{z}^T u \rfloor.$

Following Fischetti and Lodi [2005], let $$(x^*,r^*)$$ be a fractional solution of the above original system. The separating MIP created below is

$\begin{array}{rlr@{\;}l} \max & (x^*)^T \alpha - \beta - w^T y \\ & f = \tilde{A}^T y + \overline{z} - \alpha \\ & \tilde{f} = \tilde{b}^T y + u^T \overline{z} - \beta\\ & \tilde{C}^T y \geq 0\\ & 0 \leq f \leq 1 - \epsilon \\ & 0 \leq \tilde{f} \leq 1 - \epsilon\\ & 0 \leq y, \overline{z} \leq 1 - \epsilon.\\ & \alpha \in Z^m, \beta \in Z. \end{array}$

Here, $$w$$ is a weight vector; it's idea is to make the sum over all components of $$y$$ as small as possible, in order to generate sparse cuts.

We perform the following additional computations:

• If the lower bounds on $$x_i$$ or $$r_j$$ are finite, we shift the variable to have a zero lower bound, i.e., we replace it by $$x_i - \ell_i$$ (or $$r_j - u_j$$). This is helpful in several ways: As seen above, the resulting inequalities/formulations simplify. Moreover, it allows to drop a variable if $$x^*_i = 0$$, see the next comment. If the lower bounds are not finite, but the upper bounds are finite, we can complement the variable. If the variables are free, the above formulation changes as follows: For free continuous variables, we require $$\tilde{C}^T y = 0$$. For a free integer variable $$x_j$$ (which rarely occurs in practice), we require $$f_j = 0$$, i.e., we force that $$(\tilde{A}^T y + \overline{z})_j = \alpha_j$$.
• If $$x^*_j = 0 = \ell_j$$ (after the above preprocessing), we drop variable $$\alpha_j$$ from the formulation. Let $$(\alpha^*, \beta^*, y^*, \overline{z}^*)$$ be an optimal solution to the separating MIP. Then we can compute $$\alpha_j = \lfloor(\tilde{A}_j^T y^* + \overline{z}^*)\rfloor$$.
• If $$x^*_i = u_i$$, we complement the variable and drop it from the formulation, since the lower bound is 0 afterwards.
• If a variable has been shifted or complemented, we have to recompute $$\beta$$ with the original lhs/rhs.
• If a continuous variable $$r_j$$ is free, we have to force equality for the corresponding components in $$y^T \tilde{C} \, r \geq 0$$.
• If an integer variable $$x_i$$ is free, we are not allowed to round the cut down. In this case, the combintation of rows and bounds has to be integral. We force this by requiring that $$f_i = 0$$.
• If contconvert is true, some integral variables are randomly treated as if they were continuous. This has the effect that in the resulting cut the corresponding coefficient has value 0. This makes the cuts more sparse. Moreover, the separation problems should become easier.
• If required, i.e., parameter primalseparation is true, we force a primal separation step. For this we require that the cut is tight at the currently best solution. To get reliable solutions we relax equality by EPSILONVALUE.
• If required (via parameters useobjub or useobjlb), we add a row corresponding to the objective function with respect to the current lower and upper bounds.
Parameters
 scip SCIP data structure sepa separator sepadata separator data mipdata data for sub-MIP

Definition at line 1021 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ subscipSetParams()

 static SCIP_RETCODE subscipSetParams ( SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata )
static

sets parameters for subscip

Parameters
 sepadata separator data mipdata data for sub-MIP

Definition at line 2016 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ solveSubscip()

 static SCIP_RETCODE solveSubscip ( SCIP * scip, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_Bool * success )
static

solve subscip

Parameters
 scip SCIP data structure sepadata separator data mipdata data for sub-MIP success if setting was successful -> stop solution otherwise

Definition at line 2145 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ createCGCutDirect()

 static SCIP_RETCODE createCGCutDirect ( SCIP * scip, SCIP_SEPA * sepa, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_SOL * sol, SCIP_Real * cutcoefs, int * cutinds, SCIP_Real * cutvals, SCIP_Real * varsolvals, SCIP_Real * weights, int * nprevrows, SCIP_ROW ** prevrows, SCIP_Bool * cutoff, unsigned int * ngen )
static

Create CG-cut directly from solution of sub-MIP

Parameters
 scip SCIP data structure sepa separator sepadata separator data mipdata data for sub-MIP sol solution of sub-MIP cutcoefs cut coefficients cutinds problem indices of variables appearing in cut cutvals values of variables in cut varsolvals solution value of variables weights weights to compute cmir cut nprevrows number of previously generated rows prevrows previously generated rows cutoff whether a cutoff has been detected ngen number of generated cuts

Definition at line 2888 of file sepa_cgmip.c.

Referenced by createCGCuts().

## ◆ createCGCutCMIR()

 static SCIP_RETCODE createCGCutCMIR ( SCIP * scip, SCIP_SEPA * sepa, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_SOL * sol, SCIP_AGGRROW * aggrrow, SCIP_Real * cutcoefs, int * cutinds, SCIP_Real * cutvals, SCIP_Real * varsolvals, SCIP_Real * weights, int * boundsfortrans, SCIP_BOUNDTYPE * boundtypesfortrans, int * nprevrows, SCIP_ROW ** prevrows, SCIP_Bool * cutoff, unsigned int * ngen )
static

create CG-cut via CMIR-function

Parameters
 scip SCIP data structure sepa separator sepadata separator data mipdata data for sub-MIP sol solution of sub-MIP aggrrow aggregation row to use for creating MIR cut cutcoefs cut coefficients cutinds problem indices of variables appearing in cut cutvals values of variables in cut varsolvals solution value of variables weights weights to compute cmir cut boundsfortrans bounds for cmir function of NULL boundtypesfortrans type of bounds for cmir function or NULL nprevrows number of previously generated rows prevrows previously generated rows cutoff whether a cutoff has been detected ngen number of generated cuts

Definition at line 3104 of file sepa_cgmip.c.

Referenced by createCGCuts().

## ◆ createCGCutStrongCG()

 static SCIP_RETCODE createCGCutStrongCG ( SCIP * scip, SCIP_SEPA * sepa, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_SOL * sol, SCIP_AGGRROW * aggrrow, SCIP_Real * cutcoefs, int * cutinds, SCIP_Real * cutvals, SCIP_Real * varsolvals, SCIP_Real * weights, int * nprevrows, SCIP_ROW ** prevrows, SCIP_Bool * cutoff, unsigned int * ngen )
static

create CG-cut via strong-CG-function

Parameters
 scip SCIP data structure sepa separator sepadata separator data mipdata data for sub-MIP sol solution of sub-MIP aggrrow aggregation row to use for creating MIR cut cutcoefs cut coefficients cutinds problem indices of variables appearing in cut cutvals values of variables in cut varsolvals solution value of variables weights weights to compute cmir cut nprevrows number of previously generated rows prevrows previously generated rows cutoff whether a cutoff has been detected ngen number of generated cuts

Definition at line 3393 of file sepa_cgmip.c.

Referenced by createCGCuts().

## ◆ createCGCuts()

 static SCIP_RETCODE createCGCuts ( SCIP * scip, SCIP_SEPA * sepa, SCIP_SEPADATA * sepadata, CGMIP_MIPDATA * mipdata, SCIP_Bool * cutoff, unsigned int * ngen )
static

Create CG-cuts from solutions of sub-MIP

Parameters
 scip SCIP data structure sepa separator sepadata separator data mipdata data for sub-MIP cutoff whether a cutoff has been detected ngen number of generated cuts

Definition at line 3623 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ freeSubscip()

 static SCIP_RETCODE freeSubscip ( SCIP * scip, SCIP_SEPA * sepa, CGMIP_MIPDATA * mipdata )
static

frees "subscip" data

Parameters
 scip SCIP data structure sepa separator data mipdata data for sub-MIP

Definition at line 3777 of file sepa_cgmip.c.

Referenced by SCIP_DECL_SEPAEXECLP().

## ◆ SCIP_DECL_SEPAINIT()

 static SCIP_DECL_SEPAINIT ( sepaInitCGMIP )
static

initialization method of separator (called after problem was transformed)

Definition at line 3866 of file sepa_cgmip.c.

References DEFAULT_RANDSEED, NULL, SCIP_CALL, SCIP_OKAY, SCIPcreateRandom(), SCIPsepaGetData(), and TRUE.

## ◆ SCIP_DECL_SEPAEXIT()

 static SCIP_DECL_SEPAEXIT ( sepaExitCGMIP )
static

deinitialization method of separator (called before transformed problem is freed)

Definition at line 3881 of file sepa_cgmip.c.

References NULL, SCIP_OKAY, SCIPfreeRandom(), and SCIPsepaGetData().

## ◆ SCIP_DECL_SEPACOPY()

 static SCIP_DECL_SEPACOPY ( sepaCopyCGMIP )
static

copy method for separator plugins (called when SCIP copies plugins)

Definition at line 3895 of file sepa_cgmip.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPincludeSepaCGMIP(), SCIPsepaGetName(), and SEPA_NAME.

## ◆ SCIP_DECL_SEPAFREE()

 static SCIP_DECL_SEPAFREE ( sepaFreeCGMIP )
static

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

Definition at line 3910 of file sepa_cgmip.c.

## ◆ SCIP_DECL_SEPAEXECLP()

 static SCIP_DECL_SEPAEXECLP ( sepaExeclpCGMIP )
static

LP solution separation method of separator

Definition at line 3932 of file sepa_cgmip.c.