Classes
struct	SCIP_LPi
	LP interface. More...

struct	SCIP_LPiState

struct	SCIP_LPiNorms

Macros
#define	UNSCALEDFEAS_CHECK 2
	uncomment to turn off scaling More...

Functions
const char *	SCIPlpiGetSolverName (void)
	gets name and version of LP solver More...

const char *	SCIPlpiGetSolverDesc (void)
	gets description of LP solver (developer, webpage, ...) More...

void *	SCIPlpiGetSolverPointer (SCIP_LPI *lpi)
	gets pointer for LP solver - use only with great care More...

SCIP_RETCODE	SCIPlpiSetIntegralityInformation (SCIP_LPI lpi, int ncols, int intInfo)
	pass integrality information to LP solver More...

SCIP_Bool	SCIPlpiHasPrimalSolve (void)
	informs about availability of a primal simplex solving method More...

SCIP_Bool	SCIPlpiHasDualSolve (void)
	informs about availability of a dual simplex solving method More...

SCIP_Bool	SCIPlpiHasBarrierSolve (void)
	informs about availability of a barrier solving method More...

LPI Creation and Destruction Methods
SCIP_RETCODE	SCIPlpiCreate (SCIP_LPI *lpi, SCIP_MESSAGEHDLR messagehdlr, const char *name, SCIP_OBJSEN objsen)
	creates an LP problem object More...

SCIP_RETCODE	SCIPlpiFree (SCIP_LPI **lpi)
	deletes an LP problem object More...

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)
	copies LP data with column matrix into LP solver More...

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 More...

SCIP_RETCODE	SCIPlpiDelCols (SCIP_LPI *lpi, int firstcol, int lastcol)
	deletes all columns in the given range from LP More...

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 More...

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 More...

static void	deleteRowsAndUpdateCurrentBasis (SCIP_LPI *lpi, const DenseBooleanColumn &rows_to_delete)
	delete rows from LP and update the current basis More...

SCIP_RETCODE	SCIPlpiDelRows (SCIP_LPI *lpi, int firstrow, int lastrow)
	deletes all rows in the given range from LP More...

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 More...

SCIP_RETCODE	SCIPlpiClear (SCIP_LPI *lpi)
	clears the whole LP More...

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 More...

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 More...

SCIP_RETCODE	SCIPlpiChgCoef (SCIP_LPI *lpi, int row, int col, SCIP_Real newval)
	changes a single coefficient More...

SCIP_RETCODE	SCIPlpiChgObjsen (SCIP_LPI *lpi, SCIP_OBJSEN objsen)
	changes the objective sense More...

SCIP_RETCODE	SCIPlpiChgObj (SCIP_LPI lpi, int ncols, const int ind, const SCIP_Real *obj)
	changes objective values of columns in the LP More...

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 More...

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 More...

Data Accessing Methods
SCIP_RETCODE	SCIPlpiGetNRows (SCIP_LPI lpi, int nrows)
	gets the number of rows in the LP More...

SCIP_RETCODE	SCIPlpiGetNCols (SCIP_LPI lpi, int ncols)
	gets the number of columns in the LP More...

SCIP_RETCODE	SCIPlpiGetObjsen (SCIP_LPI lpi, SCIP_OBJSEN objsen)
	gets objective sense of the LP More...

SCIP_RETCODE	SCIPlpiGetNNonz (SCIP_LPI lpi, int nnonz)
	gets the number of nonzero elements in the LP constraint matrix More...

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. More...

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. More...

SCIP_RETCODE	SCIPlpiGetColNames (SCIP_LPI lpi, int firstcol, int lastcol, char colnames, char namestorage, int namestoragesize, int *storageleft)
	gets column names More...

SCIP_RETCODE	SCIPlpiGetRowNames (SCIP_LPI lpi, int firstrow, int lastrow, char rownames, char namestorage, int namestoragesize, int *storageleft)
	gets row names More...

SCIP_RETCODE	SCIPlpiGetObj (SCIP_LPI lpi, int firstcol, int lastcol, SCIP_Real vals)
	gets objective coefficients from LP problem object More...

SCIP_RETCODE	SCIPlpiGetBounds (SCIP_LPI lpi, int firstcol, int lastcol, SCIP_Real lbs, SCIP_Real *ubs)
	gets current bounds from LP problem object More...

SCIP_RETCODE	SCIPlpiGetSides (SCIP_LPI lpi, int firstrow, int lastrow, SCIP_Real lhss, SCIP_Real *rhss)
	gets current row sides from LP problem object More...

SCIP_RETCODE	SCIPlpiGetCoef (SCIP_LPI lpi, int row, int col, SCIP_Real val)
	gets a single coefficient More...

Solving Methods
static void	updateScaledLP (SCIP_LPI *lpi)
	update scaled linear program More...

static bool	checkUnscaledPrimalFeasibility (SCIP_LPI *lpi)
	check primal feasibility More...

static SCIP_RETCODE	SolveInternal (SCIP_LPI *lpi, bool recursive, std::unique_ptr< TimeLimit > &time_limit)
	common function between the two LPI Solve() functions More...

SCIP_RETCODE	SCIPlpiSolvePrimal (SCIP_LPI *lpi)
	calls primal simplex to solve the LP More...

SCIP_RETCODE	SCIPlpiSolveDual (SCIP_LPI *lpi)
	calls dual simplex to solve the LP More...

SCIP_RETCODE	SCIPlpiSolveBarrier (SCIP_LPI *lpi, SCIP_Bool crossover)
	calls barrier or interior point algorithm to solve the LP with crossover to simplex basis More...

SCIP_RETCODE	SCIPlpiStartStrongbranch (SCIP_LPI *lpi)
	start strong branching More...

SCIP_RETCODE	SCIPlpiEndStrongbranch (SCIP_LPI *lpi)
	end strong branching More...

static bool	IsDualBoundValid (ProblemStatus status)
	determine whether the dual bound is valid More...

static SCIP_RETCODE	strongbranch (SCIP_LPI lpi, int col_index, SCIP_Real psol, int itlim, SCIP_Real down, SCIP_Real up, SCIP_Bool downvalid, SCIP_Bool upvalid, int iter)
	performs strong branching iterations More...

SCIP_RETCODE	SCIPlpiStrongbranchFrac (SCIP_LPI lpi, int col_index, 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 More...

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 More...

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 More...

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 More...

Solution Information Methods
SCIP_Bool	SCIPlpiWasSolved (SCIP_LPI *lpi)
	returns whether a solve method was called after the last modification of the LP More...

SCIP_RETCODE	SCIPlpiGetSolFeasibility (SCIP_LPI lpi, SCIP_Bool primalfeasible, SCIP_Bool *dualfeasible)
	gets information about primal and dual feasibility of the current LP solution More...

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 More...

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 More...

SCIP_Bool	SCIPlpiIsPrimalUnbounded (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be primal unbounded More...

SCIP_Bool	SCIPlpiIsPrimalInfeasible (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be primal infeasible More...

SCIP_Bool	SCIPlpiIsPrimalFeasible (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be primal feasible More...

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 More...

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 More...

SCIP_Bool	SCIPlpiIsDualUnbounded (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be dual unbounded More...

SCIP_Bool	SCIPlpiIsDualInfeasible (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be dual infeasible More...

SCIP_Bool	SCIPlpiIsDualFeasible (SCIP_LPI *lpi)
	returns TRUE iff LP is proven to be dual feasible More...

SCIP_Bool	SCIPlpiIsOptimal (SCIP_LPI *lpi)
	returns TRUE iff LP was solved to optimality More...

SCIP_Bool	SCIPlpiIsStable (SCIP_LPI *lpi)
	returns TRUE iff current LP solution is stable More...

SCIP_Bool	SCIPlpiIsObjlimExc (SCIP_LPI *lpi)
	returns TRUE iff the objective limit was reached More...

SCIP_Bool	SCIPlpiIsIterlimExc (SCIP_LPI *lpi)
	returns TRUE iff the iteration limit was reached More...

SCIP_Bool	SCIPlpiIsTimelimExc (SCIP_LPI *lpi)
	returns TRUE iff the time limit was reached More...

int	SCIPlpiGetInternalStatus (SCIP_LPI *lpi)
	returns the internal solution status of the solver More...

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 More...

SCIP_RETCODE	SCIPlpiGetObjval (SCIP_LPI lpi, SCIP_Real objval)
	gets objective value of solution More...

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 for feasible LPs More...

SCIP_RETCODE	SCIPlpiGetPrimalRay (SCIP_LPI lpi, SCIP_Real ray)
	gets primal ray for unbounded LPs More...

SCIP_RETCODE	SCIPlpiGetDualfarkas (SCIP_LPI lpi, SCIP_Real dualfarkas)
	gets dual Farkas proof for infeasibility More...

SCIP_RETCODE	SCIPlpiGetIterations (SCIP_LPI lpi, int iterations)
	gets the number of LP iterations of the last solve call More...

SCIP_RETCODE	SCIPlpiGetRealSolQuality (SCIP_LPI lpi, SCIP_LPSOLQUALITY qualityindicator, SCIP_Real quality)
	gets information about the quality of an LP solution More...

LP Basis Methods
static SCIP_BASESTAT	ConvertGlopVariableStatus (VariableStatus status, Fractional rc)
	convert Glop variable basis status to SCIP status More...

static SCIP_BASESTAT	ConvertGlopConstraintStatus (ConstraintStatus status, Fractional dual)
	convert Glop constraint basis status to SCIP status More...

static VariableStatus	ConvertSCIPVariableStatus (int status)
	Convert SCIP variable status to Glop status. More...

static VariableStatus	ConvertSCIPConstraintStatusToSlackStatus (int status)
	Convert a SCIP constraint status to its corresponding Glop slack VariableStatus. More...

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 More...

SCIP_RETCODE	SCIPlpiSetBase (SCIP_LPI lpi, const int cstat, const int *rstat)
	sets current basis status for columns and rows More...

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 More...

SCIP_RETCODE	SCIPlpiGetBInvRow (SCIP_LPI lpi, int r, SCIP_Real coef, int inds, int ninds)
	get row of inverse basis matrix B^-1 More...

SCIP_RETCODE	SCIPlpiGetBInvCol (SCIP_LPI lpi, int c, SCIP_Real coef, int inds, int ninds)
	get column of inverse basis matrix B^-1 More...

SCIP_RETCODE	SCIPlpiGetBInvARow (SCIP_LPI lpi, int r, const SCIP_Real binvrow, SCIP_Real coef, int inds, int *ninds)
	get row of inverse basis matrix times constraint matrix B^-1 * A More...

SCIP_RETCODE	SCIPlpiGetBInvACol (SCIP_LPI lpi, int c, SCIP_Real coef, int inds, int ninds)
	get column of inverse basis matrix times constraint matrix B^-1 * A More...

LP State Methods
SCIP_RETCODE	SCIPlpiGetState (SCIP_LPI lpi, BMS_BLKMEM blkmem, SCIP_LPISTATE **lpistate)
	stores LPi state (like basis information) into lpistate object More...

SCIP_RETCODE	SCIPlpiSetState (SCIP_LPI lpi, BMS_BLKMEM blkmem, const 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() More...

SCIP_RETCODE	SCIPlpiClearState (SCIP_LPI *lpi)
	clears current LPi state (like basis information) of the solver More...

SCIP_RETCODE	SCIPlpiFreeState (SCIP_LPI lpi, BMS_BLKMEM blkmem, SCIP_LPISTATE **lpistate)
	frees LPi state information More...

SCIP_Bool	SCIPlpiHasStateBasis (SCIP_LPI lpi, SCIP_LPISTATE lpistate)
	checks, whether the given LP state contains simplex basis information More...

SCIP_RETCODE	SCIPlpiReadState (SCIP_LPI lpi, const char fname)
	reads LP state (like basis information from a file More...

SCIP_RETCODE	SCIPlpiWriteState (SCIP_LPI lpi, const char fname)
	writes LPi state (i.e. More...

LP Pricing Norms Methods
SCIP_RETCODE	SCIPlpiGetNorms (SCIP_LPI lpi, BMS_BLKMEM blkmem, SCIP_LPINORMS **lpinorms)
	stores LPi pricing norms information More...

SCIP_RETCODE	SCIPlpiSetNorms (SCIP_LPI lpi, BMS_BLKMEM blkmem, const 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() More...

SCIP_RETCODE	SCIPlpiFreeNorms (SCIP_LPI lpi, BMS_BLKMEM blkmem, SCIP_LPINORMS **lpinorms)
	frees pricing norms information More...

Parameter Methods
SCIP_RETCODE	SCIPlpiGetIntpar (SCIP_LPI lpi, SCIP_LPPARAM type, int ival)
	gets integer parameter of LP More...

SCIP_RETCODE	SCIPlpiSetIntpar (SCIP_LPI *lpi, SCIP_LPPARAM type, int ival)
	sets integer parameter of LP More...

SCIP_RETCODE	SCIPlpiGetRealpar (SCIP_LPI lpi, SCIP_LPPARAM type, SCIP_Real dval)
	gets floating point parameter of LP More...

SCIP_RETCODE	SCIPlpiSetRealpar (SCIP_LPI *lpi, SCIP_LPPARAM type, SCIP_Real dval)
	sets floating point parameter of LP More...

Numerical Methods
SCIP_Real	SCIPlpiInfinity (SCIP_LPI *lpi)
	returns value treated as infinity in the LP solver More...

SCIP_Bool	SCIPlpiIsInfinity (SCIP_LPI *lpi, SCIP_Real val)
	checks if given value is treated as infinity in the LP solver More...

File Interface Methods
SCIP_RETCODE	SCIPlpiReadLP (SCIP_LPI lpi, const char fname)
	reads LP from a file More...

SCIP_RETCODE	SCIPlpiWriteLP (SCIP_LPI lpi, const char fname)
	writes LP to a file More...

Variables
static char	glopname [128]

Macro Definition Documentation

◆ UNSCALEDFEAS_CHECK

#define UNSCALEDFEAS_CHECK 2

uncomment to turn off scaling

define feasibility check to possibly reoptimize: 0: no check, 1: completely new check, 2: check unscaled variable and activity values

Definition at line 126 of file lpi_glop.cc.

Function Documentation

◆ checkUnscaledPrimalFeasibility()

static bool checkUnscaledPrimalFeasibility ( SCIP_LPI * lpi )

static

check primal feasibility

Parameters

lpi	LP interface structure

Definition at line 1300 of file lpi_glop.cc.

◆ ConvertGlopConstraintStatus()

static SCIP_BASESTAT ConvertGlopConstraintStatus	(	ConstraintStatus	status,
		Fractional	dual
	)

static

convert Glop constraint basis status to SCIP status

Parameters

status	constraint status
dual	dual variable value

Definition at line 2220 of file lpi_glop.cc.

◆ ConvertGlopVariableStatus()

static SCIP_BASESTAT ConvertGlopVariableStatus	(	VariableStatus	status,
		Fractional	rc
	)

static

convert Glop variable basis status to SCIP status

Parameters

status	variable status
rc	reduced cost of variable

Definition at line 2195 of file lpi_glop.cc.

◆ ConvertSCIPConstraintStatusToSlackStatus()

static VariableStatus ConvertSCIPConstraintStatusToSlackStatus ( int status )

static

Convert a SCIP constraint status to its corresponding Glop slack VariableStatus.

Note that we swap the upper/lower bounds.

Parameters

status SCIP constraint status

Definition at line 2270 of file lpi_glop.cc.

◆ ConvertSCIPVariableStatus()

static VariableStatus ConvertSCIPVariableStatus ( int status )

static

Convert SCIP variable status to Glop status.

Parameters

status SCIP variable status

Definition at line 2245 of file lpi_glop.cc.

◆ deleteRowsAndUpdateCurrentBasis()

static void deleteRowsAndUpdateCurrentBasis	(	SCIP_LPI *	lpi,
		const DenseBooleanColumn &	rows_to_delete
	)

static

delete rows from LP and update the current basis

Parameters

lpi	LP interface structure
rows_to_delete	array to mark rows that should be deleted

Definition at line 535 of file lpi_glop.cc.

◆ IsDualBoundValid()

static bool IsDualBoundValid ( ProblemStatus status )

static

determine whether the dual bound is valid

Parameters

status status to be checked

Definition at line 1493 of file lpi_glop.cc.

◆ SCIPlpiAddCols()

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 335 of file lpi_glop.cc.

◆ SCIPlpiAddRows()

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 466 of file lpi_glop.cc.

◆ SCIPlpiChgBounds()

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 or NULL if ncols is zero
lb	values for the new lower bounds or NULL if ncols is zero
ub	values for the new upper bounds or NULL if ncols is zero

Definition at line 637 of file lpi_glop.cc.

◆ SCIPlpiChgCoef()

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 701 of file lpi_glop.cc.

◆ SCIPlpiChgObj()

SCIP_RETCODE SCIPlpiChgObj	(	SCIP_LPI *	lpi,
		int	ncols,
		const int *	ind,
		const 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 749 of file lpi_glop.cc.

◆ SCIPlpiChgObjsen()

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 724 of file lpi_glop.cc.

◆ SCIPlpiChgSides()

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 676 of file lpi_glop.cc.

◆ SCIPlpiClear()

SCIP_RETCODE SCIPlpiClear ( SCIP_LPI * lpi )

clears the whole LP

Parameters

lpi	LP interface structure

Definition at line 621 of file lpi_glop.cc.

◆ SCIPlpiClearState()

SCIP_RETCODE SCIPlpiClearState ( SCIP_LPI * lpi )

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

Parameters

lpi	LP interface structure

Definition at line 2703 of file lpi_glop.cc.

◆ SCIPlpiCreate()

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 224 of file lpi_glop.cc.

◆ SCIPlpiDelCols()

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 407 of file lpi_glop.cc.

◆ SCIPlpiDelColset()

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 431 of file lpi_glop.cc.

◆ SCIPlpiDelRows()

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 565 of file lpi_glop.cc.

◆ SCIPlpiDelRowset()

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 587 of file lpi_glop.cc.

◆ SCIPlpiEndStrongbranch()

SCIP_RETCODE SCIPlpiEndStrongbranch ( SCIP_LPI * lpi )

end strong branching

Parameters

lpi	LP interface structure

Definition at line 1479 of file lpi_glop.cc.

◆ SCIPlpiExistsDualRay()

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 1845 of file lpi_glop.cc.

◆ SCIPlpiExistsPrimalRay()

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 1782 of file lpi_glop.cc.

◆ SCIPlpiFree()

SCIP_RETCODE SCIPlpiFree ( SCIP_LPI ** lpi )

deletes an LP problem object

Parameters

lpi	pointer to an LP interface structure

Definition at line 266 of file lpi_glop.cc.

◆ SCIPlpiFreeNorms()

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, or NULL

Definition at line 2824 of file lpi_glop.cc.

◆ SCIPlpiFreeState()

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 2716 of file lpi_glop.cc.

◆ SCIPlpiGetBase()

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 2291 of file lpi_glop.cc.

◆ SCIPlpiGetBasisInd()

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 2358 of file lpi_glop.cc.

◆ SCIPlpiGetBInvACol()

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

get 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 of the column
inds	array to store the non-zero indices, or NULL
ninds	pointer to store the number of non-zero indices, or NULL (-1: if we do not store sparsity information)

Definition at line 2585 of file lpi_glop.cc.

◆ SCIPlpiGetBInvARow()

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

get 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 of the row
inds	array to store the non-zero indices, or NULL
ninds	pointer to store the number of non-zero indices, or NULL (-1: if we do not store sparsity information)

Definition at line 2529 of file lpi_glop.cc.

◆ SCIPlpiGetBInvCol()

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

get 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
inds	array to store the non-zero indices, or NULL
ninds	pointer to store the number of non-zero indices, or NULL (-1: if we do not store sparsity information)

Definition at line 2465 of file lpi_glop.cc.

◆ SCIPlpiGetBInvRow()

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

get 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
inds	array to store the non-zero indices, or NULL
ninds	pointer to store the number of non-zero indices, or NULL (-1: if we do not store sparsity information)

Definition at line 2394 of file lpi_glop.cc.

◆ SCIPlpiGetBounds()

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 1188 of file lpi_glop.cc.

◆ SCIPlpiGetCoef()

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 1248 of file lpi_glop.cc.

◆ SCIPlpiGetColNames()

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) or NULL if namestoragesize is zero
namestorage	storage for col names or NULL if namestoragesize is zero
namestoragesize	size of namestorage (if 0, storageleft returns the storage needed)
storageleft	amount of storage left (if < 0 the namestorage was not big enough) or NULL if namestoragesize is zero

Definition at line 1115 of file lpi_glop.cc.

◆ SCIPlpiGetCols()

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 row indices of constraint matrix entries, or NULL
val	buffer to store values of constraint matrix entries, or NULL

Definition at line 984 of file lpi_glop.cc.

◆ SCIPlpiGetDualfarkas()

SCIP_RETCODE SCIPlpiGetDualfarkas	(	SCIP_LPI *	lpi,
		SCIP_Real *	dualfarkas
	)

gets dual Farkas proof for infeasibility

Parameters

lpi	LP interface structure
dualfarkas	dual Farkas row multipliers

Definition at line 2112 of file lpi_glop.cc.

◆ SCIPlpiGetInternalStatus()

int SCIPlpiGetInternalStatus ( SCIP_LPI * lpi )

returns the internal solution status of the solver

Parameters

lpi	LP interface structure

Definition at line 2003 of file lpi_glop.cc.

◆ SCIPlpiGetIntpar()

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 2851 of file lpi_glop.cc.

◆ SCIPlpiGetIterations()

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 2132 of file lpi_glop.cc.

◆ SCIPlpiGetNCols()

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 930 of file lpi_glop.cc.

◆ SCIPlpiGetNNonz()

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 964 of file lpi_glop.cc.

◆ SCIPlpiGetNorms()

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

stores LPi pricing norms information

Todo:: store primal norms as well?

Parameters

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

Definition at line 2792 of file lpi_glop.cc.

◆ SCIPlpiGetNRows()

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 913 of file lpi_glop.cc.

◆ SCIPlpiGetObj()

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 1163 of file lpi_glop.cc.

◆ SCIPlpiGetObjsen()

SCIP_RETCODE SCIPlpiGetObjsen	(	SCIP_LPI *	lpi,
		SCIP_OBJSEN *	objsen
	)

gets objective sense of the LP

Parameters

lpi	LP interface structure
objsen	pointer to store objective sense

Definition at line 947 of file lpi_glop.cc.

◆ SCIPlpiGetObjval()

SCIP_RETCODE SCIPlpiGetObjval	(	SCIP_LPI *	lpi,
		SCIP_Real *	objval
	)

gets objective value of solution

Parameters

lpi	LP interface structure
objval	stores the objective value

Definition at line 2029 of file lpi_glop.cc.

◆ SCIPlpiGetPrimalRay()

SCIP_RETCODE SCIPlpiGetPrimalRay	(	SCIP_LPI *	lpi,
		SCIP_Real *	ray
	)

gets primal ray for unbounded LPs

Parameters

lpi	LP interface structure
ray	primal ray

Definition at line 2092 of file lpi_glop.cc.

◆ SCIPlpiGetRealpar()

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 3005 of file lpi_glop.cc.

◆ SCIPlpiGetRealSolQuality()

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 2151 of file lpi_glop.cc.

◆ SCIPlpiGetRowNames()

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) or NULL if namestoragesize is zero
namestorage	storage for row names or NULL if namestoragesize is zero
namestoragesize	size of namestorage (if 0, -storageleft returns the storage needed)
storageleft	amount of storage left (if < 0 the namestorage was not big enough) or NULL if namestoragesize is zero

Definition at line 1139 of file lpi_glop.cc.

◆ SCIPlpiGetRows()

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 column indices of constraint matrix entries, or NULL
val	buffer to store values of constraint matrix entries, or NULL

Definition at line 1050 of file lpi_glop.cc.

◆ SCIPlpiGetSides()

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 1218 of file lpi_glop.cc.

◆ SCIPlpiGetSol()

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 for feasible LPs

Before calling this function, the caller must ensure that the LP has been solved to optimality, i.e., that SCIPlpiIsOptimal() returns true.

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 2048 of file lpi_glop.cc.

◆ SCIPlpiGetSolFeasibility()

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

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

The feasibility information is with respect to the last solving call and it is only relevant if SCIPlpiWasSolved() returns true. If the LP is changed, this information might be invalidated.

Note that primalfeasible and dualfeasible should only return true if the solver has proved the respective LP to be feasible. Thus, the return values should be equal to the values of SCIPlpiIsPrimalFeasible() and SCIPlpiIsDualFeasible(), respectively. Note that if feasibility cannot be proved, they should return false (even if the problem might actually be feasible).

Parameters

lpi	LP interface structure
primalfeasible	pointer to store primal feasibility status
dualfeasible	pointer to store dual feasibility status

Definition at line 1759 of file lpi_glop.cc.

◆ SCIPlpiGetSolverDesc()

const char* SCIPlpiGetSolverDesc ( void )

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

Definition at line 146 of file lpi_glop.cc.

◆ SCIPlpiGetSolverName()

const char* SCIPlpiGetSolverName ( void )

gets name and version of LP solver

Definition at line 137 of file lpi_glop.cc.

◆ SCIPlpiGetSolverPointer()

void* SCIPlpiGetSolverPointer ( SCIP_LPI * lpi )

gets pointer for LP solver - use only with great care

Parameters

lpi	pointer to an LP interface structure

Definition at line 154 of file lpi_glop.cc.

◆ SCIPlpiGetState()

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 2669 of file lpi_glop.cc.

◆ SCIPlpiHasBarrierSolve()

SCIP_Bool SCIPlpiHasBarrierSolve ( void )

informs about availability of a barrier solving method

Definition at line 208 of file lpi_glop.cc.

◆ SCIPlpiHasDualRay()

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 1860 of file lpi_glop.cc.

◆ SCIPlpiHasDualSolve()

SCIP_Bool SCIPlpiHasDualSolve ( void )

informs about availability of a dual simplex solving method

Definition at line 200 of file lpi_glop.cc.

◆ SCIPlpiHasPrimalRay()

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 1795 of file lpi_glop.cc.

◆ SCIPlpiHasPrimalSolve()

SCIP_Bool SCIPlpiHasPrimalSolve ( void )

informs about availability of a primal simplex solving method

Definition at line 192 of file lpi_glop.cc.

◆ SCIPlpiHasStateBasis()

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), or NULL

Definition at line 2733 of file lpi_glop.cc.

◆ SCIPlpiIgnoreInstability()

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 2014 of file lpi_glop.cc.

◆ SCIPlpiInfinity()

SCIP_Real SCIPlpiInfinity ( SCIP_LPI * lpi )

returns value treated as infinity in the LP solver

Parameters

lpi	LP interface structure

Definition at line 3121 of file lpi_glop.cc.

◆ SCIPlpiIsDualFeasible()

SCIP_Bool SCIPlpiIsDualFeasible ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be dual feasible

Parameters

lpi	LP interface structure

Definition at line 1897 of file lpi_glop.cc.

◆ SCIPlpiIsDualInfeasible()

SCIP_Bool SCIPlpiIsDualInfeasible ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be dual infeasible

Parameters

lpi	LP interface structure

Definition at line 1885 of file lpi_glop.cc.

◆ SCIPlpiIsDualUnbounded()

SCIP_Bool SCIPlpiIsDualUnbounded ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be dual unbounded

Parameters

lpi	LP interface structure

Definition at line 1873 of file lpi_glop.cc.

◆ SCIPlpiIsInfinity()

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 3130 of file lpi_glop.cc.

◆ SCIPlpiIsIterlimExc()

SCIP_Bool SCIPlpiIsIterlimExc ( SCIP_LPI * lpi )

returns TRUE iff the iteration limit was reached

Parameters

lpi	LP interface structure

Definition at line 1979 of file lpi_glop.cc.

◆ SCIPlpiIsObjlimExc()

SCIP_Bool SCIPlpiIsObjlimExc ( SCIP_LPI * lpi )

returns TRUE iff the objective limit was reached

Parameters

lpi	LP interface structure

Definition at line 1968 of file lpi_glop.cc.

◆ SCIPlpiIsOptimal()

SCIP_Bool SCIPlpiIsOptimal ( SCIP_LPI * lpi )

returns TRUE iff LP was solved to optimality

Parameters

lpi	LP interface structure

Definition at line 1910 of file lpi_glop.cc.

◆ SCIPlpiIsPrimalFeasible()

SCIP_Bool SCIPlpiIsPrimalFeasible ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be primal feasible

Parameters

lpi	LP interface structure

Definition at line 1830 of file lpi_glop.cc.

◆ SCIPlpiIsPrimalInfeasible()

SCIP_Bool SCIPlpiIsPrimalInfeasible ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be primal infeasible

Parameters

lpi	LP interface structure

Definition at line 1817 of file lpi_glop.cc.

◆ SCIPlpiIsPrimalUnbounded()

SCIP_Bool SCIPlpiIsPrimalUnbounded ( SCIP_LPI * lpi )

returns TRUE iff LP is proven to be primal unbounded

Parameters

lpi	LP interface structure

Definition at line 1806 of file lpi_glop.cc.

◆ SCIPlpiIsStable()

SCIP_Bool SCIPlpiIsStable ( SCIP_LPI * lpi )

returns TRUE iff current LP solution is stable

This function should return true if the solution is reliable, i.e., feasible and optimal (or proven infeasible/unbounded) with respect to the original problem. The optimality status might be with respect to a scaled version of the problem, but the solution might not be feasible to the unscaled original problem; in this case, SCIPlpiIsStable() should return false.

Parameters

lpi	LP interface structure

Definition at line 1927 of file lpi_glop.cc.

◆ SCIPlpiIsTimelimExc()

SCIP_Bool SCIPlpiIsTimelimExc ( SCIP_LPI * lpi )

returns TRUE iff the time limit was reached

Parameters

lpi	LP interface structure

Definition at line 1992 of file lpi_glop.cc.

◆ SCIPlpiLoadColLP()

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 299 of file lpi_glop.cc.

◆ SCIPlpiReadLP()

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

reads LP from a file

Parameters

lpi	LP interface structure
fname	file name

Definition at line 3153 of file lpi_glop.cc.

◆ SCIPlpiReadState()

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

reads LP state (like basis information from a file

Parameters

lpi	LP interface structure
fname	file name

Definition at line 2745 of file lpi_glop.cc.

◆ SCIPlpiScaleCol()

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 835 of file lpi_glop.cc.

◆ SCIPlpiScaleRow()

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 772 of file lpi_glop.cc.

◆ SCIPlpiSetBase()

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

sets current basis status for columns and rows

Parameters

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

Definition at line 2325 of file lpi_glop.cc.

◆ SCIPlpiSetIntegralityInformation()

SCIP_RETCODE SCIPlpiSetIntegralityInformation	(	SCIP_LPI *	lpi,
		int	ncols,
		int *	intInfo
	)

pass integrality information to LP solver

Parameters

lpi	pointer to an LP interface structure
ncols	length of integrality array
intInfo	integrality array (0: continuous, 1: integer). May be NULL iff ncols is 0.

Definition at line 166 of file lpi_glop.cc.

◆ SCIPlpiSetIntpar()

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

sets integer parameter of LP

Parameters

lpi	LP interface structure
type	parameter number
ival	parameter value

Definition at line 2909 of file lpi_glop.cc.

◆ SCIPlpiSetNorms()

SCIP_RETCODE SCIPlpiSetNorms	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		const 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, or NULL

Definition at line 2809 of file lpi_glop.cc.

◆ SCIPlpiSetRealpar()

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 3057 of file lpi_glop.cc.

◆ SCIPlpiSetState()

SCIP_RETCODE SCIPlpiSetState	(	SCIP_LPI *	lpi,
		BMS_BLKMEM *	blkmem,
		const 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), or NULL

Definition at line 2687 of file lpi_glop.cc.

◆ SCIPlpiSolveBarrier()

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 1448 of file lpi_glop.cc.

◆ SCIPlpiSolveDual()

SCIP_RETCODE SCIPlpiSolveDual ( SCIP_LPI * lpi )

calls dual simplex to solve the LP

Parameters

lpi	LP interface structure

Definition at line 1430 of file lpi_glop.cc.

◆ SCIPlpiSolvePrimal()

SCIP_RETCODE SCIPlpiSolvePrimal ( SCIP_LPI * lpi )

calls primal simplex to solve the LP

Parameters

lpi	LP interface structure

Definition at line 1412 of file lpi_glop.cc.

◆ SCIPlpiStartStrongbranch()

SCIP_RETCODE SCIPlpiStartStrongbranch ( SCIP_LPI * lpi )

start strong branching

Parameters

lpi	LP interface structure

Definition at line 1464 of file lpi_glop.cc.

◆ SCIPlpiStrongbranchesFrac()

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 1641 of file lpi_glop.cc.

◆ SCIPlpiStrongbranchesInt()

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 1698 of file lpi_glop.cc.

◆ SCIPlpiStrongbranchFrac()

SCIP_RETCODE SCIPlpiStrongbranchFrac	(	SCIP_LPI *	lpi,
		int	col_index,
		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_index	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 1612 of file lpi_glop.cc.

◆ SCIPlpiStrongbranchInt()

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 1671 of file lpi_glop.cc.

◆ SCIPlpiWasSolved()

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 1739 of file lpi_glop.cc.

◆ SCIPlpiWriteLP()

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

writes LP to a file

Parameters

lpi	LP interface structure
fname	file name

Definition at line 3176 of file lpi_glop.cc.

◆ SCIPlpiWriteState()

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

writes LPi state (i.e.

basis information) to a file

Parameters

lpi	LP interface structure
fname	file name

Definition at line 2759 of file lpi_glop.cc.

◆ SolveInternal()

static SCIP_RETCODE SolveInternal	(	SCIP_LPI *	lpi,
		bool	recursive,
		std::unique_ptr< TimeLimit > &	time_limit
	)

static

common function between the two LPI Solve() functions

Parameters

lpi	LP interface structure
recursive	Is this a recursive call?
time_limit	time limit

Definition at line 1354 of file lpi_glop.cc.

◆ strongbranch()

static SCIP_RETCODE strongbranch	(	SCIP_LPI *	lpi,
		int	col_index,
		SCIP_Real	psol,
		int	itlim,
		SCIP_Real *	down,
		SCIP_Real *	up,
		SCIP_Bool *	downvalid,
		SCIP_Bool *	upvalid,
		int *	iter
	)

static

performs strong branching iterations

Parameters

lpi	LP interface structure
col_index	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 1502 of file lpi_glop.cc.

◆ updateScaledLP()

static void updateScaledLP ( SCIP_LPI * lpi )

static

update scaled linear program

Parameters

lpi	LP interface structure

Definition at line 1280 of file lpi_glop.cc.

Variable Documentation

◆ glopname

char glopname[128]

static

Definition at line 134 of file lpi_glop.cc.

Classes

Macros

Functions

Variables

Macro Definition Documentation

◆ UNSCALEDFEAS_CHECK

Function Documentation

◆ checkUnscaledPrimalFeasibility()

◆ ConvertGlopConstraintStatus()

◆ ConvertGlopVariableStatus()

◆ ConvertSCIPConstraintStatusToSlackStatus()

◆ ConvertSCIPVariableStatus()

◆ deleteRowsAndUpdateCurrentBasis()

◆ IsDualBoundValid()

◆ SCIPlpiAddCols()

◆ SCIPlpiAddRows()

◆ SCIPlpiChgBounds()

◆ SCIPlpiChgCoef()

◆ SCIPlpiChgObj()

◆ SCIPlpiChgObjsen()

◆ SCIPlpiChgSides()

◆ SCIPlpiClear()

◆ SCIPlpiClearState()

◆ SCIPlpiCreate()

◆ SCIPlpiDelCols()

◆ SCIPlpiDelColset()

◆ SCIPlpiDelRows()

◆ SCIPlpiDelRowset()

◆ SCIPlpiEndStrongbranch()

◆ SCIPlpiExistsDualRay()

◆ SCIPlpiExistsPrimalRay()

◆ SCIPlpiFree()

◆ SCIPlpiFreeNorms()

◆ SCIPlpiFreeState()

◆ SCIPlpiGetBase()

◆ SCIPlpiGetBasisInd()

◆ SCIPlpiGetBInvACol()

◆ SCIPlpiGetBInvARow()

◆ SCIPlpiGetBInvCol()

◆ SCIPlpiGetBInvRow()

◆ SCIPlpiGetBounds()

◆ SCIPlpiGetCoef()

◆ SCIPlpiGetColNames()

◆ SCIPlpiGetCols()

◆ SCIPlpiGetDualfarkas()

◆ SCIPlpiGetInternalStatus()

◆ SCIPlpiGetIntpar()

◆ SCIPlpiGetIterations()

◆ SCIPlpiGetNCols()

◆ SCIPlpiGetNNonz()

◆ SCIPlpiGetNorms()

◆ SCIPlpiGetNRows()

◆ SCIPlpiGetObj()

◆ SCIPlpiGetObjsen()

◆ SCIPlpiGetObjval()

◆ SCIPlpiGetPrimalRay()

◆ SCIPlpiGetRealpar()

◆ SCIPlpiGetRealSolQuality()

◆ SCIPlpiGetRowNames()

◆ SCIPlpiGetRows()

◆ SCIPlpiGetSides()

◆ SCIPlpiGetSol()

◆ SCIPlpiGetSolFeasibility()

◆ SCIPlpiGetSolverDesc()

◆ SCIPlpiGetSolverName()

◆ SCIPlpiGetSolverPointer()

◆ SCIPlpiGetState()

◆ SCIPlpiHasBarrierSolve()

◆ SCIPlpiHasDualRay()

◆ SCIPlpiHasDualSolve()

◆ SCIPlpiHasPrimalRay()

◆ SCIPlpiHasPrimalSolve()

◆ SCIPlpiHasStateBasis()

◆ SCIPlpiIgnoreInstability()

◆ SCIPlpiInfinity()

◆ SCIPlpiIsDualFeasible()

◆ SCIPlpiIsDualInfeasible()

◆ SCIPlpiIsDualUnbounded()

◆ SCIPlpiIsInfinity()

◆ SCIPlpiIsIterlimExc()