lpi_grb.c File Reference

Detailed Description

LP interface for Gurobi.

Author

Marc Pfetsch

This LPI is beta!

Several things are missing in the Gurobi interface that make this LPI relatively useless:

• Gurobi currently does not allow to access the basis inverse.
• Strong branching is supported, but not documented.
• The support of ranged rows is complicated for the user: one has to keep track of the additional variables, which are added to generate a ranged row. Hence, one would need to adapt the count of variables and retrieve the information of ranged rows to get the correct answers.

While the first two issues only influence the performance, the third is critical for some problems, which contain ranged rows.

Definition in file lpi_grb.c.

#include <assert.h>
#include <string.h>
#include "gurobi_c.h"
#include "lpi/lpi.h"
#include "scip/pub_message.h"

Go to the source code of this file.

Macros
#define	CHECK_ZERO(messagehdlr, x)
#define	SVECTOR   GRBsvec
#define	GRB_METHOD_DUAL   GRB_LPMETHOD_DUAL
#define	GRB_METHOD_PRIMAL   GRB_LPMETHOD_PRIMAL
#define	GRB_INT_PAR_METHOD   GRB_INT_PAR_LPMETHOD
#define	SCIP_SINGLEPACKETSIZE   (sizeof(SCIP_SINGLEPACKET)*8)
#define	SCIP_DUALPACKETSIZE   (sizeof(SCIP_DUALPACKET)*4)
#define	COLS_PER_PACKET   SCIP_DUALPACKETSIZE
#define	ROWS_PER_PACKET   SCIP_DUALPACKETSIZE
#define	GRB_REFACTORMAXITERS   50 /* maximal number of iterations allowed for producing a refactorization of the basis */
#define	NUMINTPARAM   4
#define	NUMDBLPARAM   6

Typedefs
typedef unsigned int	SCIP_SINGLEPACKET
typedef unsigned int	SCIP_DUALPACKET
typedef SCIP_DUALPACKET	COLPACKET
typedef SCIP_DUALPACKET	ROWPACKET
typedef struct GRBParam	GRBPARAM

Functions
Miscellaneous Methods
const char *	SCIPlpiGetSolverName (void)
const char *	SCIPlpiGetSolverDesc (void)
void *	SCIPlpiGetSolverPointer (SCIP_LPI *lpi)
LPI Creation and Destruction Methods
SCIP_RETCODE	SCIPlpiCreate (SCIP_LPI **lpi, SCIP_MESSAGEHDLR *messagehdlr, const char *name, SCIP_OBJSEN objsen)
SCIP_RETCODE	SCIPlpiFree (SCIP_LPI **lpi)
Modification Methods
SCIP_RETCODE	SCIPlpiLoadColLP (SCIP_LPI *lpi, SCIP_OBJSEN objsen, int ncols, const SCIP_Real *obj, const SCIP_Real *lb, const SCIP_Real *ub, char **colnames, int nrows, const SCIP_Real *lhs, const SCIP_Real *rhs, char **rownames, int nnonz, const int *beg, const int *ind, const SCIP_Real *val)
SCIP_RETCODE	SCIPlpiAddCols (SCIP_LPI *lpi, int ncols, const SCIP_Real *obj, const SCIP_Real *lb, const SCIP_Real *ub, char **colnames, int nnonz, const int *beg, const int *ind, const SCIP_Real *val)
SCIP_RETCODE	SCIPlpiDelCols (SCIP_LPI *lpi, int firstcol, int lastcol)
SCIP_RETCODE	SCIPlpiDelColset (SCIP_LPI *lpi, int *dstat)
SCIP_RETCODE	SCIPlpiAddRows (SCIP_LPI *lpi, int nrows, const SCIP_Real *lhs, const SCIP_Real *rhs, char **rownames, int nnonz, const int *beg, const int *ind, const SCIP_Real *val)
SCIP_RETCODE	SCIPlpiDelRows (SCIP_LPI *lpi, int firstrow, int lastrow)
SCIP_RETCODE	SCIPlpiDelRowset (SCIP_LPI *lpi, int *dstat)
SCIP_RETCODE	SCIPlpiClear (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiChgBounds (SCIP_LPI *lpi, int ncols, const int *ind, const SCIP_Real *lb, const SCIP_Real *ub)
SCIP_RETCODE	SCIPlpiChgSides (SCIP_LPI *lpi, int nrows, const int *ind, const SCIP_Real *lhs, const SCIP_Real *rhs)
SCIP_RETCODE	SCIPlpiChgCoef (SCIP_LPI *lpi, int row, int col, SCIP_Real newval)
SCIP_RETCODE	SCIPlpiChgObjsen (SCIP_LPI *lpi, SCIP_OBJSEN objsen)
SCIP_RETCODE	SCIPlpiChgObj (SCIP_LPI *lpi, int ncols, int *ind, SCIP_Real *obj)
SCIP_RETCODE	SCIPlpiScaleRow (SCIP_LPI *lpi, int row, SCIP_Real scaleval)
SCIP_RETCODE	SCIPlpiScaleCol (SCIP_LPI *lpi, int col, SCIP_Real scaleval)
Data Accessing Methods
SCIP_RETCODE	SCIPlpiGetNRows (SCIP_LPI *lpi, int *nrows)
SCIP_RETCODE	SCIPlpiGetNCols (SCIP_LPI *lpi, int *ncols)
SCIP_RETCODE	SCIPlpiGetNNonz (SCIP_LPI *lpi, int *nnonz)
SCIP_RETCODE	SCIPlpiGetCols (SCIP_LPI *lpi, int firstcol, int lastcol, SCIP_Real *lb, SCIP_Real *ub, int *nnonz, int *beg, int *ind, SCIP_Real *val)
SCIP_RETCODE	SCIPlpiGetRows (SCIP_LPI *lpi, int firstrow, int lastrow, SCIP_Real *lhs, SCIP_Real *rhs, int *nnonz, int *beg, int *ind, SCIP_Real *val)
SCIP_RETCODE	SCIPlpiGetColNames (SCIP_LPI *lpi, int firstcol, int lastcol, char **colnames, char *namestorage, int namestoragesize, int *storageleft)
SCIP_RETCODE	SCIPlpiGetRowNames (SCIP_LPI *lpi, int firstrow, int lastrow, char **rownames, char *namestorage, int namestoragesize, int *storageleft)
SCIP_RETCODE	SCIPlpiGetObjsen (SCIP_LPI *lpi, SCIP_OBJSEN *objsen)
SCIP_RETCODE	SCIPlpiGetObj (SCIP_LPI *lpi, int firstcol, int lastcol, SCIP_Real *vals)
SCIP_RETCODE	SCIPlpiGetBounds (SCIP_LPI *lpi, int firstcol, int lastcol, SCIP_Real *lbs, SCIP_Real *ubs)
SCIP_RETCODE	SCIPlpiGetSides (SCIP_LPI *lpi, int firstrow, int lastrow, SCIP_Real *lhss, SCIP_Real *rhss)
SCIP_RETCODE	SCIPlpiGetCoef (SCIP_LPI *lpi, int row, int col, SCIP_Real *val)
Solving Methods
SCIP_RETCODE	SCIPlpiSolvePrimal (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiSolveDual (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiSolveBarrier (SCIP_LPI *lpi, SCIP_Bool crossover)
SCIP_RETCODE	SCIPlpiStartStrongbranch (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiEndStrongbranch (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiStrongbranchFrac (SCIP_LPI *lpi, int col, SCIP_Real psol, int itlim, SCIP_Real *down, SCIP_Real *up, SCIP_Bool *downvalid, SCIP_Bool *upvalid, int *iter)
SCIP_RETCODE	SCIPlpiStrongbranchesFrac (SCIP_LPI *lpi, int *cols, int ncols, SCIP_Real *psols, int itlim, SCIP_Real *down, SCIP_Real *up, SCIP_Bool *downvalid, SCIP_Bool *upvalid, int *iter)
SCIP_RETCODE	SCIPlpiStrongbranchInt (SCIP_LPI *lpi, int col, SCIP_Real psol, int itlim, SCIP_Real *down, SCIP_Real *up, SCIP_Bool *downvalid, SCIP_Bool *upvalid, int *iter)
SCIP_RETCODE	SCIPlpiStrongbranchesInt (SCIP_LPI *lpi, int *cols, int ncols, SCIP_Real *psols, int itlim, SCIP_Real *down, SCIP_Real *up, SCIP_Bool *downvalid, SCIP_Bool *upvalid, int *iter)
Solution Information Methods
SCIP_Bool	SCIPlpiWasSolved (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiGetSolFeasibility (SCIP_LPI *lpi, SCIP_Bool *primalfeasible, SCIP_Bool *dualfeasible)
SCIP_Bool	SCIPlpiExistsPrimalRay (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiHasPrimalRay (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsPrimalUnbounded (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsPrimalInfeasible (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsPrimalFeasible (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiExistsDualRay (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiHasDualRay (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsDualUnbounded (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsDualInfeasible (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsDualFeasible (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsOptimal (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsStable (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsObjlimExc (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsIterlimExc (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsTimelimExc (SCIP_LPI *lpi)
int	SCIPlpiGetInternalStatus (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiIgnoreInstability (SCIP_LPI *lpi, SCIP_Bool *success)
SCIP_RETCODE	SCIPlpiGetObjval (SCIP_LPI *lpi, SCIP_Real *objval)
SCIP_RETCODE	SCIPlpiGetSol (SCIP_LPI *lpi, SCIP_Real *objval, SCIP_Real *primsol, SCIP_Real *dualsol, SCIP_Real *activity, SCIP_Real *redcost)
SCIP_RETCODE	SCIPlpiGetPrimalRay (SCIP_LPI *lpi, SCIP_Real *ray)
SCIP_RETCODE	SCIPlpiGetDualfarkas (SCIP_LPI *lpi, SCIP_Real *dualfarkas)
SCIP_RETCODE	SCIPlpiGetIterations (SCIP_LPI *lpi, int *iterations)
SCIP_RETCODE	SCIPlpiGetRealSolQuality (SCIP_LPI *lpi, SCIP_LPSOLQUALITY qualityindicator, SCIP_Real *quality)
LP Basis Methods
SCIP_RETCODE	SCIPlpiGetBase (SCIP_LPI *lpi, int *cstat, int *rstat)
SCIP_RETCODE	SCIPlpiSetBase (SCIP_LPI *lpi, int *cstat, int *rstat)
SCIP_RETCODE	SCIPlpiGetBasisInd (SCIP_LPI *lpi, int *bind)
SCIP_RETCODE	SCIPlpiGetBInvRow (SCIP_LPI *lpi, int r, SCIP_Real *coef)
SCIP_RETCODE	SCIPlpiGetBInvCol (SCIP_LPI *lpi, int c, SCIP_Real *coef)
SCIP_RETCODE	SCIPlpiGetBInvARow (SCIP_LPI *lpi, int r, const SCIP_Real *binvrow, SCIP_Real *coef)
SCIP_RETCODE	SCIPlpiGetBInvACol (SCIP_LPI *lpi, int c, SCIP_Real *coef)
LP State Methods
SCIP_RETCODE	SCIPlpiGetState (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPISTATE **lpistate)
SCIP_RETCODE	SCIPlpiSetState (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPISTATE *lpistate)
SCIP_RETCODE	SCIPlpiClearState (SCIP_LPI *lpi)
SCIP_RETCODE	SCIPlpiFreeState (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPISTATE **lpistate)
SCIP_Bool	SCIPlpiHasStateBasis (SCIP_LPI *lpi, SCIP_LPISTATE *lpistate)
SCIP_RETCODE	SCIPlpiReadState (SCIP_LPI *lpi, const char *fname)
SCIP_RETCODE	SCIPlpiWriteState (SCIP_LPI *lpi, const char *fname)
LP Pricing Norms Methods
SCIP_RETCODE	SCIPlpiGetNorms (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPINORMS **lpinorms)
SCIP_RETCODE	SCIPlpiSetNorms (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPINORMS *lpinorms)
SCIP_RETCODE	SCIPlpiFreeNorms (SCIP_LPI *lpi, BMS_BLKMEM *blkmem, SCIP_LPINORMS **lpinorms)
Parameter Methods
SCIP_RETCODE	SCIPlpiGetIntpar (SCIP_LPI *lpi, SCIP_LPPARAM type, int *ival)
SCIP_RETCODE	SCIPlpiSetIntpar (SCIP_LPI *lpi, SCIP_LPPARAM type, int ival)
SCIP_RETCODE	SCIPlpiGetRealpar (SCIP_LPI *lpi, SCIP_LPPARAM type, SCIP_Real *dval)
SCIP_RETCODE	SCIPlpiSetRealpar (SCIP_LPI *lpi, SCIP_LPPARAM type, SCIP_Real dval)
Numerical Methods
SCIP_Real	SCIPlpiInfinity (SCIP_LPI *lpi)
SCIP_Bool	SCIPlpiIsInfinity (SCIP_LPI *lpi, SCIP_Real val)
File Interface Methods
SCIP_RETCODE	SCIPlpiReadLP (SCIP_LPI *lpi, const char *fname)
SCIP_RETCODE	SCIPlpiWriteLP (SCIP_LPI *lpi, const char *fname)

Macro Definition Documentation

#define CHECK_ZERO	(		messagehdlr,
			x
	)

Value:

{ int _restat_;                      \
      if( (_restat_ = (x)) != 0 )                                       \
      {                                                                 \
         SCIPmessagePrintWarning((messagehdlr), "Gurobi error %d: %s\n", _restat_, GRBgeterrormsg(grbenv)); \
         return SCIP_LPERROR;                                           \
      }                                                                 \
   }

Definition at line 52 of file lpi_grb.c.

Referenced by SCIPlpiAddCols(), SCIPlpiAddRows(), SCIPlpiChgBounds(), SCIPlpiChgCoef(), SCIPlpiChgObj(), SCIPlpiChgObjsen(), SCIPlpiChgSides(), SCIPlpiClear(), SCIPlpiClearState(), SCIPlpiCreate(), SCIPlpiDelCols(), SCIPlpiDelColset(), SCIPlpiDelRows(), SCIPlpiDelRowset(), SCIPlpiFree(), SCIPlpiGetBase(), SCIPlpiGetBasisInd(), SCIPlpiGetBInvACol(), SCIPlpiGetBInvARow(), SCIPlpiGetBInvCol(), SCIPlpiGetBInvRow(), SCIPlpiGetBounds(), SCIPlpiGetCoef(), SCIPlpiGetCols(), SCIPlpiGetDualfarkas(), SCIPlpiGetNCols(), SCIPlpiGetNNonz(), SCIPlpiGetNRows(), SCIPlpiGetObj(), SCIPlpiGetObjsen(), SCIPlpiGetObjval(), SCIPlpiGetPrimalRay(), SCIPlpiGetRealpar(), SCIPlpiGetRealSolQuality(), SCIPlpiGetRows(), SCIPlpiGetSides(), SCIPlpiGetSol(), SCIPlpiGetSolFeasibility(), SCIPlpiGetState(), SCIPlpiHasDualRay(), SCIPlpiIsDualFeasible(), SCIPlpiIsDualUnbounded(), SCIPlpiIsPrimalFeasible(), SCIPlpiLoadColLP(), SCIPlpiReadLP(), SCIPlpiReadState(), SCIPlpiScaleCol(), SCIPlpiScaleRow(), SCIPlpiSetBase(), SCIPlpiSetRealpar(), SCIPlpiSetState(), SCIPlpiSolveBarrier(), SCIPlpiSolveDual(), SCIPlpiSolvePrimal(), SCIPlpiWriteLP(), and SCIPlpiWriteState().

#define SVECTOR   GRBsvec

Definition at line 70 of file lpi_grb.c.

Referenced by SCIPlpiGetBInvACol(), SCIPlpiGetBInvARow(), SCIPlpiGetBInvCol(), and SCIPlpiGetBInvRow().

#define GRB_METHOD_DUAL   GRB_LPMETHOD_DUAL

Definition at line 74 of file lpi_grb.c.

Referenced by SCIPlpiGetSolFeasibility(), SCIPlpiHasDualRay(), SCIPlpiIsDualFeasible(), SCIPlpiIsDualUnbounded(), and SCIPlpiSolveDual().

#define GRB_METHOD_PRIMAL   GRB_LPMETHOD_PRIMAL

Definition at line 75 of file lpi_grb.c.

Referenced by SCIPlpiGetSolFeasibility(), SCIPlpiIsPrimalFeasible(), and SCIPlpiSolvePrimal().

#define GRB_INT_PAR_METHOD   GRB_INT_PAR_LPMETHOD

Definition at line 76 of file lpi_grb.c.

Referenced by SCIPlpiGetSolFeasibility(), SCIPlpiHasDualRay(), SCIPlpiIsDualFeasible(), SCIPlpiIsDualUnbounded(), SCIPlpiIsPrimalFeasible(), SCIPlpiSolveBarrier(), SCIPlpiSolveDual(), and SCIPlpiSolvePrimal().

#define SCIP_SINGLEPACKETSIZE   (sizeof(SCIP_SINGLEPACKET)*8)

each entry needs one bit of information

Definition at line 80 of file lpi_grb.c.

#define SCIP_DUALPACKETSIZE   (sizeof(SCIP_DUALPACKET)*4)

each entry needs two bits of information

Definition at line 82 of file lpi_grb.c.

#define COLS_PER_PACKET   SCIP_DUALPACKETSIZE

Definition at line 85 of file lpi_grb.c.

#define ROWS_PER_PACKET   SCIP_DUALPACKETSIZE

Definition at line 87 of file lpi_grb.c.

#define GRB_REFACTORMAXITERS   50 /* maximal number of iterations allowed for producing a refactorization of the basis */

Definition at line 93 of file lpi_grb.c.

#define NUMINTPARAM   4

Definition at line 97 of file lpi_grb.c.

#define NUMDBLPARAM   6

Definition at line 107 of file lpi_grb.c.

Typedef Documentation

typedef unsigned int SCIP_SINGLEPACKET

storing single bits in packed format

Definition at line 79 of file lpi_grb.c.

typedef unsigned int SCIP_DUALPACKET

storing bit pairs in packed format

Definition at line 81 of file lpi_grb.c.

typedef SCIP_DUALPACKET COLPACKET

Definition at line 84 of file lpi_grb.c.

typedef SCIP_DUALPACKET ROWPACKET

Definition at line 86 of file lpi_grb.c.

typedef struct GRBParam GRBPARAM

Definition at line 135 of file lpi_grb.c.

Function Documentation

const char* SCIPlpiGetSolverName

(

void

)

gets name and version of LP solver

Definition at line 1064 of file lpi_grb.c.

const char* SCIPlpiGetSolverDesc

(

void

)

gets description of LP solver (developer, webpage, ...)

Definition at line 1078 of file lpi_grb.c.

void* SCIPlpiGetSolverPointer

(

SCIP_LPI *

lpi

)

gets pointer for LP solver - use only with great care

Here we return the pointer to the model.

Parameters

lpi	pointer to an LP interface structure

Definition at line 1089 of file lpi_grb.c.

SCIP_RETCODE SCIPlpiCreate	(	SCIP_LPI **	lpi,
		SCIP_MESSAGEHDLR *	messagehdlr,
		const char *	name,
		SCIP_OBJSEN	objsen
	)

creates an LP problem object

Parameters

lpi	pointer to an LP interface structure
messagehdlr	message handler to use for printing messages, or NULL
name	problem name
objsen	objective sense

Definition at line 1108 of file lpi_grb.c.

References CHECK_ZERO, FALSE, NULL, SCIP_ALLOC, SCIP_Bool, SCIP_CALL, SCIP_LPPAR_PRICING, SCIP_OKAY, SCIP_PRICING_LPIDEFAULT, SCIP_Real, SCIPdebugMessage, SCIPlpiChgObjsen(), SCIPlpiSetIntpar(), and SCIPmessagePrintWarning().

SCIP_RETCODE SCIPlpiFree

(

SCIP_LPI **

lpi

)

deletes an LP problem object

Parameters

lpi	pointer to an LP interface structure

Definition at line 1183 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiLoadColLP	(	SCIP_LPI *	lpi,
		SCIP_OBJSEN	objsen,
		int	ncols,
		const SCIP_Real *	obj,
		const SCIP_Real *	lb,
		const SCIP_Real *	ub,
		char **	colnames,
		int	nrows,
		const SCIP_Real *	lhs,
		const SCIP_Real *	rhs,
		char **	rownames,
		int	nnonz,
		const int *	beg,
		const int *	ind,
		const SCIP_Real *	val
	)

copies LP data with column matrix into LP solver

Parameters

lpi	LP interface structure
objsen	objective sense
ncols	number of columns
obj	objective function values of columns
lb	lower bounds of columns
ub	upper bounds of columns
colnames	column names, or NULL
nrows	number of rows
lhs	left hand sides of rows
rhs	right hand sides of rows
rownames	row names, or NULL
nnonz	number of nonzero elements in the constraint matrix
beg	start index of each column in ind- and val-array
ind	row indices of constraint matrix entries
val	values of constraint matrix entries

Definition at line 1227 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL, SCIP_OBJSEN_MAXIMIZE, SCIP_OBJSEN_MINIMIZE, SCIP_OKAY, SCIP_Real, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiAddCols	(	SCIP_LPI *	lpi,
		int	ncols,
		const SCIP_Real *	obj,
		const SCIP_Real *	lb,
		const SCIP_Real *	ub,
		char **	colnames,
		int	nnonz,
		const int *	beg,
		const int *	ind,
		const SCIP_Real *	val
	)

adds columns to the LP

Parameters

lpi	LP interface structure
ncols	number of columns to be added
obj	objective function values of new columns
lb	lower bounds of new columns
ub	upper bounds of new columns
colnames	column names, or NULL
nnonz	number of nonzero elements to be added to the constraint matrix
beg	start index of each column in ind- and val-array, or NULL if nnonz == 0
ind	row indices of constraint matrix entries, or NULL if nnonz == 0
val	values of constraint matrix entries, or NULL if nnonz == 0

Definition at line 1305 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, SCIP_Real, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiDelCols	(	SCIP_LPI *	lpi,
		int	firstcol,
		int	lastcol
	)

deletes all columns in the given range from LP

Parameters

lpi	LP interface structure
firstcol	first column to be deleted
lastcol	last column to be deleted

Definition at line 1333 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiDelColset	(	SCIP_LPI *	lpi,
		int *	dstat
	)

deletes columns from SCIP_LP; the new position of a column must not be greater that its old position

Parameters

lpi	LP interface structure
dstat	deletion status of columns input: 1 if column should be deleted, 0 if not output: new position of column, -1 if column was deleted

Definition at line 1371 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiAddRows	(	SCIP_LPI *	lpi,
		int	nrows,
		const SCIP_Real *	lhs,
		const SCIP_Real *	rhs,
		char **	rownames,
		int	nnonz,
		const int *	beg,
		const int *	ind,
		const SCIP_Real *	val
	)

adds rows to the LP

Parameters

lpi	LP interface structure
nrows	number of rows to be added
lhs	left hand sides of new rows
rhs	right hand sides of new rows
rownames	row names, or NULL
nnonz	number of nonzero elements to be added to the constraint matrix
beg	start index of each row in ind- and val-array, or NULL if nnonz == 0
ind	column indices of constraint matrix entries, or NULL if nnonz == 0
val	values of constraint matrix entries, or NULL if nnonz == 0

Definition at line 1407 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiDelRows	(	SCIP_LPI *	lpi,
		int	firstrow,
		int	lastrow
	)

deletes all rows in the given range from LP

Parameters

lpi	LP interface structure
firstrow	first row to be deleted
lastrow	last row to be deleted

Definition at line 1442 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiDelRowset	(	SCIP_LPI *	lpi,
		int *	dstat
	)

deletes rows from SCIP_LP; the new position of a row must not be greater that its old position

Parameters

lpi	LP interface structure
dstat	deletion status of rows input: 1 if row should be deleted, 0 if not output: new position of row, -1 if row was deleted

Definition at line 1479 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiClear

(

SCIP_LPI *

lpi

)

clears the whole LP

Parameters

lpi	LP interface structure

Definition at line 1528 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiChgBounds	(	SCIP_LPI *	lpi,
		int	ncols,
		const int *	ind,
		const SCIP_Real *	lb,
		const SCIP_Real *	ub
	)

changes lower and upper bounds of columns

Parameters

lpi	LP interface structure
ncols	number of columns to change bounds for
ind	column indices
lb	values for the new lower bounds
ub	values for the new upper bounds

Definition at line 1548 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, and SCIPdebugPrintf.

Referenced by SCIPlpiScaleCol().

SCIP_RETCODE SCIPlpiChgSides	(	SCIP_LPI *	lpi,
		int	nrows,
		const int *	ind,
		const SCIP_Real *	lhs,
		const SCIP_Real *	rhs
	)

changes left and right hand sides of rows

Parameters

lpi	LP interface structure
nrows	number of rows to change sides for
ind	row indices
lhs	new values for left hand sides
rhs	new values for right hand sides

Definition at line 1579 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleRow().

SCIP_RETCODE SCIPlpiChgCoef	(	SCIP_LPI *	lpi,
		int	row,
		int	col,
		SCIP_Real	newval
	)

changes a single coefficient

Parameters

lpi	LP interface structure
row	row number of coefficient to change
col	column number of coefficient to change
newval	new value of coefficient

Definition at line 1611 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleCol(), and SCIPlpiScaleRow().

SCIP_RETCODE SCIPlpiChgObjsen	(	SCIP_LPI *	lpi,
		SCIP_OBJSEN	objsen
	)

changes the objective sense

Parameters

lpi	LP interface structure
objsen	new objective sense

Definition at line 1632 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OBJSEN_MAXIMIZE, SCIP_OBJSEN_MINIMIZE, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiCreate().

SCIP_RETCODE SCIPlpiChgObj	(	SCIP_LPI *	lpi,
		int	ncols,
		int *	ind,
		SCIP_Real *	obj
	)

changes objective values of columns in the LP

Parameters

lpi	LP interface structure
ncols	number of columns to change objective value for
ind	column indices to change objective value for
obj	new objective values for columns

Definition at line 1654 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleCol().

SCIP_RETCODE SCIPlpiScaleRow	(	SCIP_LPI *	lpi,
		int	row,
		SCIP_Real	scaleval
	)

multiplies a row with a non-zero scalar; for negative scalars, the row's sense is switched accordingly

Parameters

lpi	LP interface structure
row	row number to scale
scaleval	scaling multiplier

Definition at line 1674 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, SCIPlpiChgCoef(), SCIPlpiChgSides(), and SCIPlpiGetRows().

SCIP_RETCODE SCIPlpiScaleCol	(	SCIP_LPI *	lpi,
		int	col,
		SCIP_Real	scaleval
	)

multiplies a column with a non-zero scalar; the objective value is multiplied with the scalar, and the bounds are divided by the scalar; for negative scalars, the column's bounds are switched

Parameters

lpi	LP interface structure
col	column number to scale
scaleval	scaling multiplier

Definition at line 1731 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, SCIPlpiChgBounds(), SCIPlpiChgCoef(), SCIPlpiChgObj(), SCIPlpiGetCols(), and SCIPlpiGetObj().

SCIP_RETCODE SCIPlpiGetNRows	(	SCIP_LPI *	lpi,
		int *	nrows
	)

gets the number of rows in the LP

Parameters

lpi	LP interface structure
nrows	pointer to store the number of rows

Definition at line 1806 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetNCols	(	SCIP_LPI *	lpi,
		int *	ncols
	)

gets the number of columns in the LP

Parameters

lpi	LP interface structure
ncols	pointer to store the number of cols

Definition at line 1822 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetNNonz	(	SCIP_LPI *	lpi,
		int *	nnonz
	)

gets the number of nonzero elements in the LP constraint matrix

Parameters

lpi	LP interface structure
nnonz	pointer to store the number of nonzeros

Definition at line 1838 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetCols	(	SCIP_LPI *	lpi,
		int	firstcol,
		int	lastcol,
		SCIP_Real *	lb,
		SCIP_Real *	ub,
		int *	nnonz,
		int *	beg,
		int *	ind,
		SCIP_Real *	val
	)

gets columns from LP problem object; the arrays have to be large enough to store all values Either both, lb and ub, have to be NULL, or both have to be non-NULL, either nnonz, beg, ind, and val have to be NULL, or all of them have to be non-NULL.

Parameters

lpi	LP interface structure
firstcol	first column to get from LP
lastcol	last column to get from LP
lb	buffer to store the lower bound vector, or NULL
ub	buffer to store the upper bound vector, or NULL
nnonz	pointer to store the number of nonzero elements returned, or NULL
beg	buffer to store start index of each column in ind- and val-array, or NULL
ind	buffer to store column indices of constraint matrix entries, or NULL
val	buffer to store values of constraint matrix entries, or NULL

Definition at line 1857 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleCol().

SCIP_RETCODE SCIPlpiGetRows	(	SCIP_LPI *	lpi,
		int	firstrow,
		int	lastrow,
		SCIP_Real *	lhs,
		SCIP_Real *	rhs,
		int *	nnonz,
		int *	beg,
		int *	ind,
		SCIP_Real *	val
	)

gets rows from LP problem object; the arrays have to be large enough to store all values. Either both, lhs and rhs, have to be NULL, or both have to be non-NULL, either nnonz, beg, ind, and val have to be NULL, or all of them have to be non-NULL.

Parameters

lpi	LP interface structure
firstrow	first row to get from LP
lastrow	last row to get from LP
lhs	buffer to store left hand side vector, or NULL
rhs	buffer to store right hand side vector, or NULL
nnonz	pointer to store the number of nonzero elements returned, or NULL
beg	buffer to store start index of each row in ind- and val-array, or NULL
ind	buffer to store row indices of constraint matrix entries, or NULL
val	buffer to store values of constraint matrix entries, or NULL

Definition at line 1914 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleRow().

SCIP_RETCODE SCIPlpiGetColNames	(	SCIP_LPI *	lpi,
		int	firstcol,
		int	lastcol,
		char **	colnames,
		char *	namestorage,
		int	namestoragesize,
		int *	storageleft
	)

gets column names

Parameters

lpi	LP interface structure
firstcol	first column to get name from LP
lastcol	last column to get name from LP
colnames	pointers to column names (of size at least lastcol-firstcol+1)
namestorage	storage for col names
namestoragesize	size of namestorage (if 0, storageleft returns the storage needed)
storageleft	amount of storage left (if < 0 the namestorage was not big enough)

Definition at line 1969 of file lpi_grb.c.

References SCIP_LPERROR, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiGetRowNames	(	SCIP_LPI *	lpi,
		int	firstrow,
		int	lastrow,
		char **	rownames,
		char *	namestorage,
		int	namestoragesize,
		int *	storageleft
	)

gets row names

Parameters

lpi	LP interface structure
firstrow	first row to get name from LP
lastrow	last row to get name from LP
rownames	pointers to row names (of size at least lastrow-firstrow+1)
namestorage	storage for row names
namestoragesize	size of namestorage (if 0, -storageleft returns the storage needed)
storageleft	amount of storage left (if < 0 the namestorage was not big enough)

Definition at line 1984 of file lpi_grb.c.

References SCIP_LPERROR, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiGetObjsen	(	SCIP_LPI *	lpi,
		SCIP_OBJSEN *	objsen
	)

gets the objective sense of the LP

Parameters

lpi	LP interface structure
objsen	pointer to store objective sense

Definition at line 1999 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OBJSEN_MAXIMIZE, SCIP_OBJSEN_MINIMIZE, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetObj	(	SCIP_LPI *	lpi,
		int	firstcol,
		int	lastcol,
		SCIP_Real *	vals
	)

gets objective coefficients from LP problem object

Parameters

lpi	LP interface structure
firstcol	first column to get objective coefficient for
lastcol	last column to get objective coefficient for
vals	array to store objective coefficients

Definition at line 2021 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

Referenced by SCIPlpiScaleCol().

SCIP_RETCODE SCIPlpiGetBounds	(	SCIP_LPI *	lpi,
		int	firstcol,
		int	lastcol,
		SCIP_Real *	lbs,
		SCIP_Real *	ubs
	)

gets current bounds from LP problem object

Parameters

lpi	LP interface structure
firstcol	first column to get bounds for
lastcol	last column to get bounds for
lbs	array to store lower bound values, or NULL
ubs	array to store upper bound values, or NULL

Definition at line 2041 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetSides	(	SCIP_LPI *	lpi,
		int	firstrow,
		int	lastrow,
		SCIP_Real *	lhss,
		SCIP_Real *	rhss
	)

gets current row sides from LP problem object

Parameters

lpi	LP interface structure
firstrow	first row to get sides for
lastrow	last row to get sides for
lhss	array to store left hand side values, or NULL
rhss	array to store right hand side values, or NULL

Definition at line 2075 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetCoef	(	SCIP_LPI *	lpi,
		int	row,
		int	col,
		SCIP_Real *	val
	)

gets a single coefficient

Parameters

lpi	LP interface structure
row	row number of coefficient
col	column number of coefficient
val	pointer to store the value of the coefficient

Definition at line 2102 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiSolvePrimal

(

SCIP_LPI *

lpi

)

calls primal simplex to solve the LP

startFinishOptions - bits 1 - do not delete work areas and factorization at end 2 - use old factorization if same number of rows 4 - skip as much initialization of work areas as possible (work in progress)

4 does not seem to work.

Primal algorithm

Parameters

lpi	LP interface structure

Definition at line 2135 of file lpi_grb.c.

References CHECK_ZERO, FALSE, GRB_INT_PAR_METHOD, GRB_METHOD_PRIMAL, NULL, SCIP_CALL, SCIP_LPERROR, SCIP_NOMEMORY, SCIP_OKAY, SCIPdebugMessage, SCIPerrorMessage, and TRUE.

SCIP_RETCODE SCIPlpiSolveDual

(

SCIP_LPI *

lpi

)

calls dual simplex to solve the LP

startFinishOptions - bits 1 - do not delete work areas and factorization at end 2 - use old factorization if same number of rows 4 - skip as much initialization of work areas as possible (work in progress)

4 does not seem to work.

Dual algorithm

Parameters

lpi	LP interface structure

Definition at line 2247 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, GRB_METHOD_DUAL, NULL, SCIP_CALL, SCIP_LPERROR, SCIP_NOMEMORY, SCIP_OKAY, SCIPdebugMessage, SCIPerrorMessage, and TRUE.

SCIP_RETCODE SCIPlpiSolveBarrier	(	SCIP_LPI *	lpi,
		SCIP_Bool	crossover
	)

calls barrier or interior point algorithm to solve the LP with crossover to simplex basis

Parameters

lpi	LP interface structure
crossover	perform crossover

Definition at line 2350 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, NULL, SCIP_CALL, SCIP_LPERROR, SCIP_NOMEMORY, SCIP_OKAY, SCIPdebugMessage, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiStartStrongbranch

(

SCIP_LPI *

lpi

)

start strong branching - call before any strong branching

Parameters

lpi	LP interface structure

Definition at line 2464 of file lpi_grb.c.

References SCIP_OKAY.

SCIP_RETCODE SCIPlpiEndStrongbranch

(

SCIP_LPI *

lpi

)

end strong branching - call after any strong branching

Parameters

lpi	LP interface structure

Definition at line 2473 of file lpi_grb.c.

References SCIP_OKAY.

SCIP_RETCODE SCIPlpiStrongbranchFrac	(	SCIP_LPI *	lpi,
		int	col,
		SCIP_Real	psol,
		int	itlim,
		SCIP_Real *	down,
		SCIP_Real *	up,
		SCIP_Bool *	downvalid,
		SCIP_Bool *	upvalid,
		int *	iter
	)

performs strong branching iterations on one fractional candidate

Parameters

lpi	LP interface structure
col	column to apply strong branching on
psol	fractional current primal solution value of column
itlim	iteration limit for strong branchings
down	stores dual bound after branching column down
up	stores dual bound after branching column up
downvalid	stores whether the returned down value is a valid dual bound; otherwise, it can only be used as an estimate value
upvalid	stores whether the returned up value is a valid dual bound; otherwise, it can only be used as an estimate value
iter	stores total number of strong branching iterations, or -1; may be NULL

Definition at line 2661 of file lpi_grb.c.

References SCIP_CALL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiStrongbranchesFrac	(	SCIP_LPI *	lpi,
		int *	cols,
		int	ncols,
		SCIP_Real *	psols,
		int	itlim,
		SCIP_Real *	down,
		SCIP_Real *	up,
		SCIP_Bool *	downvalid,
		SCIP_Bool *	upvalid,
		int *	iter
	)

performs strong branching iterations on given fractional candidates

Parameters

lpi	LP interface structure
cols	columns to apply strong branching on
ncols	number of columns
psols	fractional current primal solution values of columns
itlim	iteration limit for strong branchings
down	stores dual bounds after branching columns down
up	stores dual bounds after branching columns up
downvalid	stores whether the returned down values are valid dual bounds; otherwise, they can only be used as an estimate values
upvalid	stores whether the returned up values are a valid dual bounds; otherwise, they can only be used as an estimate values
iter	stores total number of strong branching iterations, or -1; may be NULL

Definition at line 2682 of file lpi_grb.c.

References NULL, SCIP_CALL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiStrongbranchInt	(	SCIP_LPI *	lpi,
		int	col,
		SCIP_Real	psol,
		int	itlim,
		SCIP_Real *	down,
		SCIP_Real *	up,
		SCIP_Bool *	downvalid,
		SCIP_Bool *	upvalid,
		int *	iter
	)

performs strong branching iterations on one candidate with integral value

Parameters

lpi	LP interface structure
col	column to apply strong branching on
psol	current integral primal solution value of column
itlim	iteration limit for strong branchings
down	stores dual bound after branching column down
up	stores dual bound after branching column up
downvalid	stores whether the returned down value is a valid dual bound; otherwise, it can only be used as an estimate value
upvalid	stores whether the returned up value is a valid dual bound; otherwise, it can only be used as an estimate value
iter	stores total number of strong branching iterations, or -1; may be NULL

Definition at line 2720 of file lpi_grb.c.

References SCIP_CALL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiStrongbranchesInt	(	SCIP_LPI *	lpi,
		int *	cols,
		int	ncols,
		SCIP_Real *	psols,
		int	itlim,
		SCIP_Real *	down,
		SCIP_Real *	up,
		SCIP_Bool *	downvalid,
		SCIP_Bool *	upvalid,
		int *	iter
	)

performs strong branching iterations on given candidates with integral values

Parameters

lpi	LP interface structure
cols	columns to apply strong branching on
ncols	number of columns
psols	current integral primal solution values of columns
itlim	iteration limit for strong branchings
down	stores dual bounds after branching columns down
up	stores dual bounds after branching columns up
downvalid	stores whether the returned down values are valid dual bounds; otherwise, they can only be used as an estimate values
upvalid	stores whether the returned up values are a valid dual bounds; otherwise, they can only be used as an estimate values
iter	stores total number of strong branching iterations, or -1; may be NULL

Definition at line 2741 of file lpi_grb.c.

References NULL, SCIP_CALL, and SCIP_OKAY.

SCIP_Bool SCIPlpiWasSolved

(

SCIP_LPI *

lpi

)

returns whether a solve method was called after the last modification of the LP

Parameters

lpi	LP interface structure

Definition at line 2790 of file lpi_grb.c.

References NULL.

SCIP_RETCODE SCIPlpiGetSolFeasibility	(	SCIP_LPI *	lpi,
		SCIP_Bool *	primalfeasible,
		SCIP_Bool *	dualfeasible
	)

gets information about primal and dual feasibility of the current LP solution

Parameters

lpi	LP interface structure
primalfeasible	stores primal feasibility status
dualfeasible	stores dual feasibility status

Definition at line 2800 of file lpi_grb.c.

References CHECK_ZERO, FALSE, GRB_INT_PAR_METHOD, GRB_METHOD_DUAL, GRB_METHOD_PRIMAL, NULL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, and TRUE.

Referenced by SCIPlpiIsPrimalUnbounded().

SCIP_Bool SCIPlpiExistsPrimalRay

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to have a primal unbounded ray (but not necessary a primal feasible point); this does not necessarily mean, that the solver knows and can return the primal ray

Parameters

lpi	LP interface structure

Definition at line 2874 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiHasPrimalRay

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to have a primal unbounded ray (but not necessary a primal feasible point), and the solver knows and can return the primal ray

Parameters

lpi	LP interface structure

Definition at line 2888 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiIsPrimalUnbounded

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be primal unbounded

Parameters

lpi	LP interface structure

Definition at line 2900 of file lpi_grb.c.

References FALSE, NULL, SCIP_Bool, SCIP_OKAY, SCIPdebugMessage, and SCIPlpiGetSolFeasibility().

SCIP_Bool SCIPlpiIsPrimalInfeasible

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be primal infeasible

Parameters

lpi	LP interface structure

Definition at line 2923 of file lpi_grb.c.

References NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiIsPrimalFeasible

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be primal feasible

Parameters

lpi	LP interface structure

Definition at line 2938 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, GRB_METHOD_PRIMAL, NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiExistsDualRay

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to have a dual unbounded ray (but not necessary a dual feasible point); this does not necessarily mean, that the solver knows and can return the dual ray

Parameters

lpi	LP interface structure

Definition at line 2959 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiHasDualRay

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to have a dual unbounded ray (but not necessary a dual feasible point), and the solver knows and can return the dual ray

Parameters

lpi	LP interface structure

Definition at line 2973 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, GRB_METHOD_DUAL, and NULL.

SCIP_Bool SCIPlpiIsDualUnbounded

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be dual unbounded

Parameters

lpi	LP interface structure

Definition at line 2990 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, GRB_METHOD_DUAL, NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiIsDualInfeasible

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be dual infeasible

Parameters

lpi	LP interface structure

Definition at line 3009 of file lpi_grb.c.

References NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiIsDualFeasible

(

SCIP_LPI *

lpi

)

returns TRUE iff LP is proven to be dual feasible

Parameters

lpi	LP interface structure

Definition at line 3023 of file lpi_grb.c.

References CHECK_ZERO, GRB_INT_PAR_METHOD, GRB_METHOD_DUAL, NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiIsOptimal

(

SCIP_LPI *

lpi

)

returns TRUE iff LP was solved to optimality

Parameters

lpi	LP interface structure

Definition at line 3042 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiIsStable

(

SCIP_LPI *

lpi

)

returns TRUE iff current LP basis is stable

Parameters

lpi	LP interface structure

Definition at line 3054 of file lpi_grb.c.

References NULL, and SCIPdebugMessage.

SCIP_Bool SCIPlpiIsObjlimExc

(

SCIP_LPI *

lpi

)

returns TRUE iff the objective limit was reached

Parameters

lpi	LP interface structure

Definition at line 3068 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiIsIterlimExc

(

SCIP_LPI *

lpi

)

returns TRUE iff the iteration limit was reached

Parameters

lpi	LP interface structure

Definition at line 3080 of file lpi_grb.c.

References NULL.

SCIP_Bool SCIPlpiIsTimelimExc

(

SCIP_LPI *

lpi

)

returns TRUE iff the time limit was reached

Parameters

lpi	LP interface structure

Definition at line 3092 of file lpi_grb.c.

References NULL.

int SCIPlpiGetInternalStatus

(

SCIP_LPI *

lpi

)

returns the internal solution status of the solver

Parameters

lpi	LP interface structure

Definition at line 3104 of file lpi_grb.c.

References NULL.

SCIP_RETCODE SCIPlpiIgnoreInstability	(	SCIP_LPI *	lpi,
		SCIP_Bool *	success
	)

tries to reset the internal status of the LP solver in order to ignore an instability of the last solving call

Parameters

lpi	LP interface structure
success	pointer to store, whether the instability could be ignored

Definition at line 3115 of file lpi_grb.c.

References FALSE, NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiGetObjval	(	SCIP_LPI *	lpi,
		SCIP_Real *	objval
	)

gets objective value of solution

Note

if the solution status is iteration limit reached (GRB_ITERATION_LIMIT), the objective value was not computed

Parameters

lpi	LP interface structure
objval	stores the objective value

Definition at line 3133 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetSol	(	SCIP_LPI *	lpi,
		SCIP_Real *	objval,
		SCIP_Real *	primsol,
		SCIP_Real *	dualsol,
		SCIP_Real *	activity,
		SCIP_Real *	redcost
	)

gets primal and dual solution vectors

Parameters

lpi	LP interface structure
objval	stores the objective value, may be NULL if not needed
primsol	primal solution vector, may be NULL if not needed
dualsol	dual solution vector, may be NULL if not needed
activity	row activity vector, may be NULL if not needed
redcost	reduced cost vector, may be NULL if not needed

Definition at line 3149 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIPABORT, SCIPdebugMessage, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiGetPrimalRay	(	SCIP_LPI *	lpi,
		SCIP_Real *	ray
	)

gets primal ray for unbounded LPs

Unbounded ray (NULL returned if none/wrong). Up to user to use delete [] on these arrays.

Parameters

lpi	LP interface structure
ray	primal ray

Definition at line 3226 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetDualfarkas	(	SCIP_LPI *	lpi,
		SCIP_Real *	dualfarkas
	)

gets dual Farkas proof for infeasibility

Infeasibility ray (NULL returned if none/wrong). Up to user to use delete [] on these arrays.

Parameters

lpi	LP interface structure
dualfarkas	dual Farkas row multipliers

Definition at line 3248 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_LPERROR, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetIterations	(	SCIP_LPI *	lpi,
		int *	iterations
	)

gets the number of LP iterations of the last solve call

Parameters

lpi	LP interface structure
iterations	pointer to store the number of iterations of the last solve call

Definition at line 3271 of file lpi_grb.c.

References NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiGetRealSolQuality	(	SCIP_LPI *	lpi,
		SCIP_LPSOLQUALITY	qualityindicator,
		SCIP_Real *	quality
	)

gets information about the quality of an LP solution

Such information is usually only available, if also a (maybe not optimal) solution is available. The LPI should return SCIP_INVALID for quality, if the requested quantity is not available.

Parameters

lpi	LP interface structure
qualityindicator	indicates which quality should be returned
quality	pointer to store quality number

Definition at line 3290 of file lpi_grb.c.

References CHECK_ZERO, NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiGetBase	(	SCIP_LPI *	lpi,
		int *	cstat,
		int *	rstat
	)

gets current basis status for columns and rows; arrays must be large enough to store the basis status

Parameters

lpi	LP interface structure
cstat	array to store column basis status, or NULL
rstat	array to store row basis status, or NULL

Definition at line 3317 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_INVALIDDATA, SCIP_OKAY, SCIPABORT, SCIPdebugMessage, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiSetBase	(	SCIP_LPI *	lpi,
		int *	cstat,
		int *	rstat
	)

sets current basis status for columns and rows

Whats changed since last solve. Is only used when startFinishOptions used in dual or primal. Bit 1 - number of rows/columns has not changed (so work arrays valid) 2 - matrix has not changed 4 - if matrix has changed only by adding rows 8 - if matrix has changed only by adding columns 16 - row lbs not changed 32 - row ubs not changed 64 - column objective not changed 128 - column lbs not changed 256 - column ubs not changed 512 - basis not changed (up to user to set this to 0) top bits may be used internally

Parameters

lpi	LP interface structure
cstat	array with column basis status
rstat	array with row basis status

Definition at line 3407 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_INVALIDDATA, SCIP_OKAY, SCIPABORT, SCIPdebugMessage, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiGetBasisInd	(	SCIP_LPI *	lpi,
		int *	bind
	)

returns the indices of the basic columns and rows; basic column n gives value n, basic row m gives value -1-m

Parameters

lpi	LP interface structure
bind	pointer to store basis indices ready to keep number of rows entries

Definition at line 3486 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL_QUIET, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetBInvRow	(	SCIP_LPI *	lpi,
		int	r,
		SCIP_Real *	coef
	)

get dense row of inverse basis matrix B^-1

Note

The LP interface defines slack variables to have coefficient +1. This means that if, internally, the LP solver uses a -1 coefficient, then rows associated with slacks variables whose coefficient is -1, should be negated; see also the explanation in lpi.h.

Parameters

lpi	LP interface structure
r	row number
coef	pointer to store the coefficients of the row

Definition at line 3563 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL_QUIET, SCIP_OKAY, SCIPdebugMessage, and SVECTOR.

SCIP_RETCODE SCIPlpiGetBInvCol	(	SCIP_LPI *	lpi,
		int	c,
		SCIP_Real *	coef
	)

get dense column of inverse basis matrix B^-1

Note

The LP interface defines slack variables to have coefficient +1. This means that if, internally, the LP solver uses a -1 coefficient, then rows associated with slacks variables whose coefficient is -1, should be negated; see also the explanation in lpi.h.

Parameters

lpi	LP interface structure
c	column number of B^-1; this is NOT the number of the column in the LP; you have to call SCIPlpiGetBasisInd() to get the array which links the B^-1 column numbers to the row and column numbers of the LP! c must be between 0 and nrows-1, since the basis has the size nrows * nrows
coef	pointer to store the coefficients of the column

Definition at line 3636 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL_QUIET, SCIP_OKAY, SCIPdebugMessage, and SVECTOR.

SCIP_RETCODE SCIPlpiGetBInvARow	(	SCIP_LPI *	lpi,
		int	r,
		const SCIP_Real *	binvrow,
		SCIP_Real *	coef
	)

get dense row of inverse basis matrix times constraint matrix B^-1 * A

Note

The LP interface defines slack variables to have coefficient +1. This means that if, internally, the LP solver uses a -1 coefficient, then rows associated with slacks variables whose coefficient is -1, should be negated; see also the explanation in lpi.h.

Parameters

lpi	LP interface structure
r	row number
binvrow	row in (A_B)^-1 from prior call to SCIPlpiGetBInvRow(), or NULL
coef	vector to return coefficients

Definition at line 3713 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL_QUIET, SCIP_OKAY, SCIPdebugMessage, and SVECTOR.

SCIP_RETCODE SCIPlpiGetBInvACol	(	SCIP_LPI *	lpi,
		int	c,
		SCIP_Real *	coef
	)

get dense column of inverse basis matrix times constraint matrix B^-1 * A

Note

The LP interface defines slack variables to have coefficient +1. This means that if, internally, the LP solver uses a -1 coefficient, then rows associated with slacks variables whose coefficient is -1, should be negated; see also the explanation in lpi.h.

Parameters

lpi	LP interface structure
c	column number
coef	vector to return coefficients

Definition at line 3776 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_CALL_QUIET, SCIP_OKAY, SCIPdebugMessage, and SVECTOR.

SCIP_RETCODE SCIPlpiGetState	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPISTATE **	lpistate
	)

stores LPi state (like basis information) into lpistate object

Parameters

lpi	LP interface structure
blkmem	block memory
lpistate	pointer to LPi state information (like basis information)

Definition at line 3841 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_ALLOC, SCIP_Bool, SCIP_CALL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiSetState	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPISTATE *	lpistate
	)

loads LPi state (like basis information) into solver; note that the LP might have been extended with additional columns and rows since the state was stored with SCIPlpiGetState()

Parameters

lpi	LP interface structure
blkmem	block memory
lpistate	LPi state information (like basis information)

Definition at line 3902 of file lpi_grb.c.

References CHECK_ZERO, NULL, REALABS, SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, and SCIPlpiIsInfinity().

SCIP_RETCODE SCIPlpiClearState

(

SCIP_LPI *

lpi

)

clears current LPi state (like basis information) of the solver

Parameters

lpi	LP interface structure

Definition at line 3965 of file lpi_grb.c.

References CHECK_ZERO, NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiFreeState	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPISTATE **	lpistate
	)

frees LPi state information

Parameters

lpi	LP interface structure
blkmem	block memory
lpistate	pointer to LPi state information (like basis information)

Definition at line 3977 of file lpi_grb.c.

References NULL, and SCIP_OKAY.

SCIP_Bool SCIPlpiHasStateBasis	(	SCIP_LPI *	lpi,
		SCIP_LPISTATE *	lpistate
	)

checks, whether the given LP state contains simplex basis information

Parameters

lpi	LP interface structure
lpistate	LP state information (like basis information)

Definition at line 3993 of file lpi_grb.c.

References NULL.

SCIP_RETCODE SCIPlpiReadState	(	SCIP_LPI *	lpi,
		const char *	fname
	)

reads LP state (like basis information from a file

Read a basis from the given filename, returns -1 on file error, 0 if no values, 1 if values

Parameters

lpi	LP interface structure
fname	file name

Definition at line 4002 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_LPERROR, SCIP_OKAY, SCIPdebugMessage, and SCIPerrorMessage.

SCIP_RETCODE SCIPlpiWriteState	(	SCIP_LPI *	lpi,
		const char *	fname
	)

writes LP state (like basis information) to a file

Write the basis in MPS format to the specified file. If writeValues true, writes values of structurals (and adds VALUES to end of NAME card)

parameters:

• filename
• bool writeValues
• int formatType (0 - normal, 1 - extra accuracy, 2 - IEEE hex)

Parameters

lpi	LP interface structure
fname	file name

Definition at line 4029 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_MAXSTRLEN, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiGetNorms	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPINORMS **	lpinorms
	)

stores LPi pricing norms information

Parameters

lpi	LP interface structure
blkmem	block memory
lpinorms	pointer to LPi pricing norms information

Definition at line 4074 of file lpi_grb.c.

References NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiSetNorms	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPINORMS *	lpinorms
	)

loads LPi pricing norms into solver; note that the LP might have been extended with additional columns and rows since the state was stored with SCIPlpiGetNorms()

Parameters

lpi	LP interface structure
blkmem	block memory
lpinorms	LPi pricing norms information

Definition at line 4090 of file lpi_grb.c.

References NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiFreeNorms	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		SCIP_LPINORMS **	lpinorms
	)

frees pricing norms information

Parameters

lpi	LP interface structure
blkmem	block memory
lpinorms	pointer to LPi pricing norms information

Definition at line 4103 of file lpi_grb.c.

References NULL, and SCIP_OKAY.

SCIP_RETCODE SCIPlpiGetIntpar	(	SCIP_LPI *	lpi,
		SCIP_LPPARAM	type,
		int *	ival
	)

gets integer parameter of LP

Parameters

lpi	LP interface structure
type	parameter number
ival	buffer to store the parameter value

Definition at line 4128 of file lpi_grb.c.

References FALSE, NULL, SCIP_CALL, SCIP_LPPAR_FASTMIP, SCIP_LPPAR_FROMSCRATCH, SCIP_LPPAR_LPINFO, SCIP_LPPAR_LPITLIM, SCIP_LPPAR_PRESOLVING, SCIP_LPPAR_PRICING, SCIP_LPPAR_SCALING, SCIP_OKAY, SCIP_PARAMETERUNKNOWN, SCIP_Real, SCIPdebugMessage, and TRUE.

SCIP_RETCODE SCIPlpiSetIntpar	(	SCIP_LPI *	lpi,
		SCIP_LPPARAM	type,
		int	ival
	)

sets integer parameter of LP

Amount of print out: 0 - none 1 - just final 2 - just factorizations 3 - as 2 plus a bit more 4 - verbose above that 8,16,32 etc just for selective SCIPdebug

Parameters

lpi	LP interface structure
type	parameter number
ival	parameter value

Definition at line 4185 of file lpi_grb.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_LPERROR, SCIP_LPPAR_FASTMIP, SCIP_LPPAR_FROMSCRATCH, SCIP_LPPAR_LPINFO, SCIP_LPPAR_LPITLIM, SCIP_LPPAR_PRESOLVING, SCIP_LPPAR_PRICING, SCIP_LPPAR_SCALING, SCIP_OKAY, SCIP_PARAMETERUNKNOWN, SCIP_PRICING_AUTO, SCIP_PRICING_DEVEX, SCIP_PRICING_FULL, SCIP_PRICING_LPIDEFAULT, SCIP_PRICING_PARTIAL, SCIP_PRICING_STEEP, SCIP_PRICING_STEEPQSTART, SCIPdebugMessage, and TRUE.

Referenced by SCIPlpiCreate().

SCIP_RETCODE SCIPlpiGetRealpar	(	SCIP_LPI *	lpi,
		SCIP_LPPARAM	type,
		SCIP_Real *	dval
	)

gets floating point parameter of LP

Parameters

lpi	LP interface structure
type	parameter number
dval	buffer to store the parameter value

Definition at line 4266 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_LPPAR_BARRIERCONVTOL, SCIP_LPPAR_DUALFEASTOL, SCIP_LPPAR_FEASTOL, SCIP_LPPAR_LOBJLIM, SCIP_LPPAR_LPTILIM, SCIP_LPPAR_MARKOWITZ, SCIP_LPPAR_UOBJLIM, SCIP_OKAY, SCIP_PARAMETERUNKNOWN, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiSetRealpar	(	SCIP_LPI *	lpi,
		SCIP_LPPARAM	type,
		SCIP_Real	dval
	)

sets floating point parameter of LP

Parameters

lpi	LP interface structure
type	parameter number
dval	parameter value

Definition at line 4319 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_CALL, SCIP_LPPAR_BARRIERCONVTOL, SCIP_LPPAR_DUALFEASTOL, SCIP_LPPAR_FEASTOL, SCIP_LPPAR_LOBJLIM, SCIP_LPPAR_LPTILIM, SCIP_LPPAR_MARKOWITZ, SCIP_LPPAR_UOBJLIM, SCIP_OKAY, SCIP_PARAMETERUNKNOWN, and SCIPdebugMessage.

SCIP_Real SCIPlpiInfinity

(

SCIP_LPI *

lpi

)

returns value treated as infinity in the LP solver

Parameters

lpi	LP interface structure

Definition at line 4379 of file lpi_grb.c.

SCIP_Bool SCIPlpiIsInfinity	(	SCIP_LPI *	lpi,
		SCIP_Real	val
	)

checks if given value is treated as infinity in the LP solver

Parameters

lpi	LP interface structure
val	value to be checked for infinity

Definition at line 4387 of file lpi_grb.c.

Referenced by SCIPlpiSetState().

SCIP_RETCODE SCIPlpiReadLP	(	SCIP_LPI *	lpi,
		const char *	fname
	)

reads LP from a file

read file in MPS format parameters: filename bool keepNames bool ignoreErrors

Parameters

lpi	LP interface structure
fname	file name

Definition at line 4408 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.

SCIP_RETCODE SCIPlpiWriteLP	(	SCIP_LPI *	lpi,
		const char *	fname
	)

writes LP to a file

write file in MPS format parameters: filename int formatType (0 - normal, 1 - extra accuracy, 2 - IEEE hex) int numberAcross (1 or 2 values should be specified on every data line in the MPS file) double objSense

Parameters

lpi	LP interface structure
fname	file name

Definition at line 4424 of file lpi_grb.c.

References CHECK_ZERO, NULL, SCIP_OKAY, and SCIPdebugMessage.