Detailed Description

methods to build and access LP relaxation information

See also: methods to interact with LP columns and LP rows

Modules
	LP Column
	public methods for LP columns

	LP Row
	public methods for LP rows

	Cuts and Cutpools
	common methods used to manipulate, generate, and strengthen cuts and to organize the cutpool

	LP Diving
	methods to initiate and conduct LP diving

Functions
SCIP_EXPORT SCIP_Bool	SCIPhasCurrentNodeLP (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisLPConstructed (SCIP *scip)

SCIP_EXPORT SCIP_RETCODE	SCIPconstructLP (SCIP scip, SCIP_Bool cutoff)

SCIP_EXPORT SCIP_RETCODE	SCIPflushLP (SCIP *scip)

SCIP_EXPORT SCIP_LPSOLSTAT	SCIPgetLPSolstat (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisLPPrimalReliable (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisLPDualReliable (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisLPRelax (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPColumnObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPLooseObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetGlobalPseudoObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetPseudoObjval (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisRootLPRelax (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPRootObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPRootColumnObjval (SCIP *scip)

SCIP_EXPORT SCIP_Real	SCIPgetLPRootLooseObjval (SCIP *scip)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPColsData (SCIP scip, SCIP_COL *cols, int ncols)

SCIP_EXPORT SCIP_COL **	SCIPgetLPCols (SCIP *scip)

SCIP_EXPORT int	SCIPgetNLPCols (SCIP *scip)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPRowsData (SCIP scip, SCIP_ROW *rows, int nrows)

SCIP_EXPORT SCIP_ROW **	SCIPgetLPRows (SCIP *scip)

SCIP_EXPORT int	SCIPgetNLPRows (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPallColsInLP (SCIP *scip)

SCIP_EXPORT SCIP_Bool	SCIPisLPSolBasic (SCIP *scip)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPBasisInd (SCIP scip, int basisind)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPBInvRow (SCIP scip, int r, SCIP_Real coefs, int inds, int ninds)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPBInvCol (SCIP scip, int c, SCIP_Real coefs, int inds, int ninds)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPBInvARow (SCIP scip, int r, SCIP_Real binvrow, SCIP_Real coefs, int inds, int *ninds)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPBInvACol (SCIP scip, int c, SCIP_Real coefs, int inds, int ninds)

SCIP_EXPORT SCIP_RETCODE	SCIPsumLPRows (SCIP scip, SCIP_Real weights, SCIP_REALARRAY sumcoef, SCIP_Real sumlhs, SCIP_Real *sumrhs)

SCIP_EXPORT SCIP_RETCODE	SCIPwriteLP (SCIP scip, const char filename)

SCIP_EXPORT SCIP_RETCODE	SCIPwriteMIP (SCIP scip, const char filename, SCIP_Bool genericnames, SCIP_Bool origobj, SCIP_Bool lazyconss)

SCIP_EXPORT SCIP_RETCODE	SCIPgetLPI (SCIP scip, SCIP_LPI *lpi)

SCIP_EXPORT SCIP_RETCODE	SCIPprintLPSolutionQuality (SCIP scip, FILE file)

SCIP_EXPORT SCIP_RETCODE	SCIPcomputeLPRelIntPoint (SCIP scip, SCIP_Bool relaxrows, SCIP_Bool inclobjcutoff, SCIP_Real timelimit, int iterlimit, SCIP_SOL *point)

Function Documentation

◆ SCIPhasCurrentNodeLP()

SCIP_EXPORT SCIP_Bool SCIPhasCurrentNodeLP ( SCIP * scip )

returns, whether the LP was or is to be solved in the current node

Returns: whether the LP was or is to be solved in the current node.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 73 of file scip_lp.c.

References FALSE, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPtreeHasCurrentNodeLP(), Scip::tree, and TRUE.

Referenced by applyVbounds(), consdataGetGlbActivityResiduals(), DECL_CHANGESUBSCIP(), DECL_VARFIXINGS(), enforcePseudo(), execRelpscost(), getVariableRedcostScore(), redcostAvailable(), SCIP_DECL_BRANCHEXECPS(), SCIP_DECL_DISPOUTPUT(), SCIP_DECL_HEUREXEC(), SCIPperformGenericDivingAlgorithm(), SCIPStpHeurTMRunLP(), selectBranchingVertexByLp(), selectBranchingVertexByLp2Flow(), and selectBranchingVertexBySol().

◆ SCIPisLPConstructed()

SCIP_EXPORT SCIP_Bool SCIPisLPConstructed ( SCIP * scip )

returns, whether the LP of the current node is already constructed

Returns: whether the LP of the current node is already constructed.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 91 of file scip_lp.c.

References FALSE, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by applyVbounds(), createNewSol(), SCIP_DECL_HEUREXEC(), SCIPbendersComputeSubproblemLowerbound(), and SCIPbendersSolveSubproblemLP().

◆ SCIPconstructLP()

SCIP_EXPORT SCIP_RETCODE SCIPconstructLP	(	SCIP *	scip,
		SCIP_Bool *	cutoff
	)

makes sure that the LP of the current node is loaded and may be accessed through the LP information methods

Warning: Contructing the LP might change the amount of variables known in the transformed problem and therefore also the variables array of SCIP (returned by SCIPgetVars() and SCIPgetVarsData()), so it might be necessary to call one of the later method after this one

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
cutoff	pointer to store whether the node can be cut off

Definition at line 114 of file scip_lp.c.

References Scip::branchcand, Scip::cliquetable, Scip::cutpool, Scip::eventfilter, Scip::eventqueue, FALSE, Scip::lp, Scip::mem, Scip::origprob, Scip::pricestore, SCIP_Mem::probmem, Scip::reopt, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPconstructCurrentLP(), Scip::sepastore, Scip::set, Scip::stat, Scip::transprob, Scip::tree, and TRUE.

Referenced by applyVbounds(), initialiseSubproblem(), and SCIP_DECL_HEUREXEC().

◆ SCIPflushLP()

SCIP_EXPORT SCIP_RETCODE SCIPflushLP ( SCIP * scip )

makes sure that the LP of the current node is flushed

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 138 of file scip_lp.c.

References Scip::eventqueue, FALSE, Scip::lp, Scip::mem, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpFlush(), Scip::set, and TRUE.

Referenced by applyVbounds(), and SCIP_DECL_HEUREXEC().

◆ SCIPgetLPSolstat()

SCIP_EXPORT SCIP_LPSOLSTAT SCIPgetLPSolstat ( SCIP * scip )

gets solution status of current LP

Returns: the solution status of current LP.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 158 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIP_LPSOLSTAT_NOTSOLVED, SCIPcheckStage(), SCIPlpGetSolstat(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by analyzeStrongbranch(), applyBoundHeur(), applyVbounds(), collectEstLst(), DECL_CHANGESUBSCIP(), DECL_VARFIXINGS(), execRelpscost(), executeHeuristic(), fixAndPropagate(), fixDiscreteVars(), generateAndApplyBendersCuts(), generateCut(), generateCutLTI(), generateCutUnboundedLP(), getNLPFracVars(), getVariableRedcostScore(), performLPRandRounding(), performLPSimpleRounding(), performStrongbranchSOS1(), performStrongbranchWithPropagation(), polishSolution(), pricing(), redcostAvailable(), replaceByLinearConstraints(), replaceViolatedByLinearConstraints(), SCIP_DECL_BENDERSCUTEXEC(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_CONSENFOLP(), SCIP_DECL_CONSSEPALP(), SCIP_DECL_DISPOUTPUT(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_PRICERREDCOST(), SCIP_DECL_PROPEXEC(), SCIP_DECL_SEPAEXECLP(), SCIPapplyHeurSubNlp(), SCIPbendersComputeSubproblemLowerbound(), SCIPbendersExec(), SCIPbendersExecSubproblemSolve(), SCIPbendersSolveSubproblemLP(), SCIPperformGenericDivingAlgorithm(), SCIPselectVarPseudoStrongBranching(), SCIPselectVarStrongBranching(), SCIPStpHeurTMRunLP(), SCIPvisualUpdateChild(), selectBranchingVertexByLp(), selectBranchingVertexByLp2Flow(), selectBranchingVertexBySol(), selectVarMultAggrBranching(), separatePoint(), solveBilinearLP(), solveLp(), tryOneOpt(), and trySolCandidate().

◆ SCIPisLPPrimalReliable()

SCIP_EXPORT SCIP_Bool SCIPisLPPrimalReliable ( SCIP * scip )

returns whether the current LP solution passed the primal feasibility check

Returns: whether the current LP solution passed the primal feasibility check.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

returns whether the current LP solution passed the primal feasibility check

Returns: whether the current LP solution passed the primal feasibility check.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 179 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpIsPrimalReliable(), and TRUE.

◆ SCIPisLPDualReliable()

SCIP_EXPORT SCIP_Bool SCIPisLPDualReliable ( SCIP * scip )

returns whether the current LP solution passed the dual feasibility check

Returns: whether the current LP solution passed the dual feasibility check.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 197 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpIsDualReliable(), and TRUE.

Referenced by propagateRedcostBinvar(), propagateRedcostVar(), propagateRootRedcostBinvar(), and propagateRootRedcostVar().

◆ SCIPisLPRelax()

SCIP_EXPORT SCIP_Bool SCIPisLPRelax ( SCIP * scip )

returns whether the current lp is a relaxation of the current problem and its optimal objective value is a local lower bound

Returns: whether the current lp is a relaxation of the current problem and its optimal objective value is a local lower bound.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 215 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpIsRelax(), and TRUE.

Referenced by performStrongbranchWithPropagation(), and redcostAvailable().

◆ SCIPgetLPObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPObjval ( SCIP * scip )

gets objective value of current LP (which is the sum of column and loose objective value)

Returns: the objective value of current LP (which is the sum of column and loose objective value).

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

Note: This method returns the objective value of the current LP solution, which might be primal or dual infeasible if a limit was hit during solving. It must not be used as a dual bound if the LP solution status returned by SCIPgetLPSolstat() is SCIP_LPSOLSTAT_ITERLIMIT or SCIP_LPSOLSTAT_TIMELIMIT.

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 237 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetObjval(), Scip::set, Scip::transprob, and TRUE.

Referenced by applyVbounds(), execRelpscost(), executeStrongBranching(), getBranchingDecisionStrongbranchSOS1(), performLPRandRounding(), performLPSimpleRounding(), performStrongbranchSOS1(), performStrongbranchWithPropagation(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_DISPOUTPUT(), SCIP_DECL_HEUREXEC(), SCIP_DECL_PRICERREDCOST(), SCIP_DECL_PROPEXEC(), SCIP_DECL_SEPAEXECLP(), SCIPperformGenericDivingAlgorithm(), SCIPselectVarPseudoStrongBranching(), SCIPselectVarStrongBranching(), SCIPsolveDiveLP(), SCIPtryStrongbranchLPSol(), selectVarMultAggrBranching(), selectVarStart(), separateCuts(), and solveProbingLP().

◆ SCIPgetLPColumnObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPColumnObjval ( SCIP * scip )

gets part of objective value of current LP that results from COLUMN variables only

Returns: the part of objective value of current LP that results from COLUMN variables only.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 255 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetColumnObjval(), and TRUE.

◆ SCIPgetLPLooseObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPLooseObjval ( SCIP * scip )

gets part of objective value of current LP that results from LOOSE variables only

Returns: part of objective value of current LP that results from LOOSE variables only.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 273 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetLooseObjval(), Scip::set, Scip::transprob, and TRUE.

◆ SCIPgetGlobalPseudoObjval()

SCIP_EXPORT SCIP_Real SCIPgetGlobalPseudoObjval ( SCIP * scip )

gets the global pseudo objective value; that is all variables set to their best (w.r.t. the objective function) global bound

Returns: the global pseudo objective value; that is all variables set to their best (w.r.t. the objective function) global bound.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 298 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetGlobalPseudoObjval(), Scip::set, Scip::transprob, and TRUE.

Referenced by propagateCutoffboundGlobally(), and resolvePropagation().

◆ SCIPgetPseudoObjval()

SCIP_EXPORT SCIP_Real SCIPgetPseudoObjval ( SCIP * scip )

gets the pseudo objective value for the current search node; that is all variables set to their best (w.r.t. the objective function) local bound

Returns: the pseudo objective value for the current search node; that is all variables set to their best (w.r.t. the objective function) local bound.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 323 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetPseudoObjval(), Scip::set, Scip::transprob, and TRUE.

Referenced by applyOptcumulative(), and SCIP_DECL_DISPOUTPUT().

◆ SCIPisRootLPRelax()

SCIP_EXPORT SCIP_Bool SCIPisRootLPRelax ( SCIP * scip )

returns whether the root lp is a relaxation of the problem and its optimal objective value is a global lower bound

Returns: whether the root lp is a relaxation of the problem and its optimal objective value is a global lower bound.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 341 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpIsRootLPRelax(), and TRUE.

◆ SCIPgetLPRootObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPRootObjval ( SCIP * scip )

gets the objective value of the root node LP or SCIP_INVALID if the root node LP was not (yet) solved

Returns: the objective value of the root node LP or SCIP_INVALID if the root node LP was not (yet) solved.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 362 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetRootObjval(), and TRUE.

◆ SCIPgetLPRootColumnObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPRootColumnObjval ( SCIP * scip )

gets part of the objective value of the root node LP that results from COLUMN variables only; returns SCIP_INVALID if the root node LP was not (yet) solved

Returns: the part of the objective value of the root node LP that results from COLUMN variables only; or SCIP_INVALID if the root node LP was not (yet) solved.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 385 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetRootColumnObjval(), and TRUE.

◆ SCIPgetLPRootLooseObjval()

SCIP_EXPORT SCIP_Real SCIPgetLPRootLooseObjval ( SCIP * scip )

gets part of the objective value of the root node LP that results from LOOSE variables only; returns SCIP_INVALID if the root node LP was not (yet) solved

Returns: the part of the objective value of the root node LP that results from LOOSE variables only; or SCIP_INVALID if the root node LP was not (yet) solved.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 408 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetRootLooseObjval(), and TRUE.

◆ SCIPgetLPColsData()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPColsData	(	SCIP *	scip,
		SCIP_COL ***	cols,
		int *	ncols
	)

gets current LP columns along with the current number of LP columns

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
cols	pointer to store the array of LP columns, or NULL
ncols	pointer to store the number of LP columns, or NULL

Definition at line 427 of file scip_lp.c.

References FALSE, Scip::lp, NULL, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpGetCols(), SCIPlpGetNCols(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by buildMod2Matrix(), computeCut(), createCGCutDirect(), createSubscip(), extractCapacities(), extractNodes(), generateAverageNBRay(), mcfnetworkExtract(), mcfnetworkFill(), SCIP_DECL_HEUREXEC(), and SCIP_DECL_SEPAEXECLP().

◆ SCIPgetLPCols()

SCIP_EXPORT SCIP_COL** SCIPgetLPCols ( SCIP * scip )

gets current LP columns

Returns: the current LP columns.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 462 of file scip_lp.c.

References FALSE, Scip::lp, NULL, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetCols(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by findUncapacitatedArcs(), getNextFlowrow(), and mcfnetworkFill().

◆ SCIPgetNLPCols()

SCIP_EXPORT int SCIPgetNLPCols ( SCIP * scip )

gets current number of LP columns

Returns: the current number of LP columns.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 483 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetNCols(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by addFlowrowToCommodity(), aggregation(), buildMod2Matrix(), cleanupNetwork(), collectIncidentFlowCols(), deleteCommodity(), extractCapacityRows(), extractFlow(), extractFlowRows(), findUncapacitatedArcs(), generateClusterCuts(), generateZerohalfCut(), getFlowrowFit(), getIncidentNodes(), getNextFlowrow(), getNodeSimilarityScore(), identifySourcesTargets(), invertCommodity(), mcfnetworkExtract(), mcfnetworkFill(), mod2MatrixTransformContRows(), nodepairqueueCreate(), SCIP_DECL_DISPOUTPUT(), SCIP_DECL_SEPAEXECLP(), and separateCuts().

◆ SCIPgetLPRowsData()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPRowsData	(	SCIP *	scip,
		SCIP_ROW ***	rows,
		int *	nrows
	)

gets current LP rows along with the current number of LP rows

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
rows	pointer to store the array of LP rows, or NULL
nrows	pointer to store the number of LP rows, or NULL

Definition at line 505 of file scip_lp.c.

References FALSE, Scip::lp, NULL, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpGetNRows(), SCIPlpGetRows(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by aggregation(), buildMod2Matrix(), cleanupNetwork(), computeCut(), createCGCutCMIR(), createCGCutStrongCG(), createRows(), createSubscip(), extractCapacities(), extractCapacityRows(), extractFlowRows(), extractNodes(), generateAverageNBRay(), generateAverageRay(), initMatrix(), mcfnetworkExtract(), mcfnetworkFill(), mod2MatrixTransformContRows(), SCIP_DECL_HEUREXEC(), SCIP_DECL_SEPAEXECLP(), SCIPaggrRowSumRows(), SCIPapplyLockFixings(), separateCuts(), and setupAggregationData().

◆ SCIPgetLPRows()

SCIP_EXPORT SCIP_ROW** SCIPgetLPRows ( SCIP * scip )

gets current LP rows

Returns: the current LP rows.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 540 of file scip_lp.c.

References FALSE, Scip::lp, NULL, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetRows(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by applyNlobbt(), applyRepair(), computeInteriorPoint(), cutsSubstituteMIR(), cutsSubstituteStrongCG(), extractFlow(), findUncapacitatedArcs(), generateLiftedFlowCoverCut(), generateZerohalfCut(), mcfnetworkFill(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_HEUREXEC(), SCIP_DECL_RELAXEXEC(), SCIP_DECL_SEPAEXECLP(), and SCIPcutGenerationHeuristicCMIR().

◆ SCIPgetNLPRows()

SCIP_EXPORT int SCIPgetNLPRows ( SCIP * scip )

gets current number of LP rows

Returns: the current number of LP rows.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 561 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpGetNRows(), SCIPtreeIsFocusNodeLPConstructed(), Scip::tree, and TRUE.

Referenced by applyNlobbt(), applyRepair(), calcShiftVal(), computeInteriorPoint(), createCGCuts(), cutsSubstituteMIR(), cutsSubstituteStrongCG(), destroyMod2Matrix(), extractFlow(), findUncapacitatedArcs(), generateClusterCuts(), getFlowrowFit(), getIncidentNodes(), getNActiveConsScore(), getNextFlowrow(), getNodeSimilarityScore(), identifySourcesTargets(), invertCommodity(), mcfnetworkFill(), mod2rowAddRow(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_DISPOUTPUT(), SCIP_DECL_HEUREXEC(), SCIP_DECL_RELAXEXEC(), SCIP_DECL_SEPAEXECLP(), SCIPapplyLockFixings(), SCIPdummyDebugMethodForSun(), separateCuts(), and updateRowActivities().

◆ SCIPallColsInLP()

SCIP_EXPORT SCIP_Bool SCIPallColsInLP ( SCIP * scip )

returns TRUE iff all columns, i.e. every variable with non-empty column w.r.t. all ever created rows, are present in the LP, and FALSE, if there are additional already existing columns, that may be added to the LP in pricing

Returns: TRUE iff all columns, i.e. every variable with non-empty column w.r.t. all ever created rows, are present in the LP, and FALSE, if there are additional already existing columns, that may be added to the LP in pricing.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 584 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPprobAllColsInLP(), Scip::set, Scip::transprob, and TRUE.

Referenced by branch(), execRelpscost(), executeBranchingRecursive(), performRandRounding(), performSimpleRounding(), performStrongbranchWithPropagation(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_PROPEXEC(), SCIP_DECL_RELAXEXEC(), SCIPgetVarStrongbranchWithPropagation(), SCIPselectVarPseudoStrongBranching(), SCIPselectVarStrongBranching(), selectVarMultAggrBranching(), and selectVarRecursive().

◆ SCIPisLPSolBasic()

SCIP_EXPORT SCIP_Bool SCIPisLPSolBasic ( SCIP * scip )

returns whether the current LP solution is basic, i.e. is defined by a valid simplex basis

Returns: whether the current LP solution is basic, i.e. is defined by a valid simplex basis.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure

Definition at line 602 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL_ABORT, SCIPcheckStage(), SCIPlpIsSolBasic(), and TRUE.

Referenced by execRelpscost(), redcostAvailable(), SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_HEUREXEC(), SCIP_DECL_SEPAEXECLP(), and SCIPperformGenericDivingAlgorithm().

◆ SCIPgetLPBasisInd()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPBasisInd	(	SCIP *	scip,
		int *	basisind
	)

gets all indices of basic columns and rows: index i >= 0 corresponds to column i, index i < 0 to row -i-1

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
basisind	pointer to store basis indices ready to keep number of rows entries

Definition at line 621 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPcheckStage(), SCIPerrorMessage, SCIPlpGetBasisInd(), SCIPlpIsSolBasic(), and TRUE.

Referenced by SCIP_DECL_SEPAEXECLP(), and SCIPdummyDebugMethodForSun().

◆ SCIPgetLPBInvRow()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPBInvRow	(	SCIP *	scip,
		int	r,
		SCIP_Real *	coefs,
		int *	inds,
		int *	ninds
	)

gets a row from the inverse basis matrix B^-1

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
r	row number
coefs	array 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 informations)

Definition at line 649 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPcheckStage(), SCIPdebugCheckBInvRow, SCIPerrorMessage, SCIPlpGetBInvRow(), SCIPlpIsSolBasic(), and TRUE.

Referenced by SCIP_DECL_SEPAEXECLP().

◆ SCIPgetLPBInvCol()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPBInvCol	(	SCIP *	scip,
		int	c,
		SCIP_Real *	coefs,
		int *	inds,
		int *	ninds
	)

gets a column from the inverse basis matrix B^-1

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
c	column number of B^-1; this is NOT the number of the column in the LP returned by SCIPcolGetLPPos(); you have to call SCIPgetBasisInd() 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
coefs	array 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 informations)

Definition at line 684 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPcheckStage(), SCIPerrorMessage, SCIPlpGetBInvCol(), SCIPlpIsSolBasic(), and TRUE.

◆ SCIPgetLPBInvARow()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPBInvARow	(	SCIP *	scip,
		int	r,
		SCIP_Real *	binvrow,
		SCIP_Real *	coefs,
		int *	inds,
		int *	ninds
	)

gets a row from the product of inverse basis matrix B^-1 and coefficient matrix A (i.e. from B^-1 * A)

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
r	row number
binvrow	row in B^-1 from prior call to SCIPgetLPBInvRow(), or NULL
coefs	array 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 informations)

Definition at line 720 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPcheckStage(), SCIPerrorMessage, SCIPlpGetBInvARow(), SCIPlpIsSolBasic(), and TRUE.

Referenced by SCIP_DECL_SEPAEXECLP().

◆ SCIPgetLPBInvACol()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPBInvACol	(	SCIP *	scip,
		int	c,
		SCIP_Real *	coefs,
		int *	inds,
		int *	ninds
	)

gets a column from the product of inverse basis matrix B^-1 and coefficient matrix A (i.e. from B^-1 * A), i.e., it computes B^-1 * A_c with A_c being the c'th column of A

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
c	column number which can be accessed by SCIPcolGetLPPos()
coefs	array 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 informations)

Definition at line 754 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPcheckStage(), SCIPerrorMessage, SCIPlpGetBInvACol(), SCIPlpIsSolBasic(), and TRUE.

Referenced by generateAverageRay().

◆ SCIPsumLPRows()

SCIP_EXPORT SCIP_RETCODE SCIPsumLPRows	(	SCIP *	scip,
		SCIP_Real *	weights,
		SCIP_REALARRAY *	sumcoef,
		SCIP_Real *	sumlhs,
		SCIP_Real *	sumrhs
	)

calculates a weighted sum of all LP rows; for negative weights, the left and right hand side of the corresponding LP row are swapped in the summation

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
weights	row weights in row summation
sumcoef	array to store sum coefficients indexed by variables' probindex
sumlhs	pointer to store the left hand side of the row summation
sumrhs	pointer to store the right hand side of the row summation

Definition at line 787 of file scip_lp.c.

References FALSE, Scip::lp, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpSumRows(), Scip::set, Scip::transprob, and TRUE.

◆ SCIPwriteLP()

SCIP_EXPORT SCIP_RETCODE SCIPwriteLP	(	SCIP *	scip,
		const char *	filename
	)

writes current LP to a file

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
filename	file name

Definition at line 812 of file scip_lp.c.

References Scip::branchcand, Scip::cliquetable, Scip::cutpool, Scip::eventfilter, Scip::eventqueue, FALSE, Scip::lp, Scip::mem, Scip::origprob, Scip::pricestore, SCIP_Mem::probmem, Scip::reopt, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPconstructCurrentLP(), SCIPlpFlush(), SCIPlpWrite(), SCIPtreeIsFocusNodeLPConstructed(), Scip::sepastore, Scip::set, Scip::stat, Scip::transprob, Scip::tree, and TRUE.

Referenced by SCIP_DECL_DIALOGEXEC(), and SCIP_DECL_HEUREXEC().

◆ SCIPwriteMIP()

SCIP_EXPORT SCIP_RETCODE SCIPwriteMIP	(	SCIP *	scip,
		const char *	filename,
		SCIP_Bool	genericnames,
		SCIP_Bool	origobj,
		SCIP_Bool	lazyconss
	)

writes MIP relaxation of the current branch-and-bound node to a file

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

SCIP_STAGE_SOLVING

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
filename	file name
genericnames	should generic names like x_i and row_j be used in order to avoid troubles with reserved symbols?
origobj	should the original objective function be used?
lazyconss	output removable rows as lazy constraints?

Definition at line 846 of file scip_lp.c.

References Scip::eventqueue, FALSE, Scip::lp, Scip::mem, Scip::messagehdlr, SCIP_Prob::objoffset, SCIP_Prob::objscale, SCIP_Prob::objsense, Scip::origprob, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpFlush(), SCIPlpWriteMip(), Scip::set, Scip::transprob, and TRUE.

Referenced by SCIP_DECL_DIALOGEXEC().

◆ SCIPgetLPI()

SCIP_EXPORT SCIP_RETCODE SCIPgetLPI	(	SCIP *	scip,
		SCIP_LPI **	lpi
	)

gets the LP interface of SCIP; with the LPI you can use all of the methods defined in lpi/lpi.h;

Warning: You have to make sure, that the full internal state of the LPI does not change or is recovered completely after the end of the method that uses the LPI. In particular, if you manipulate the LP or its solution (e.g. by calling one of the SCIPlpiAdd...() or one of the SCIPlpiSolve...() methods), you have to check in advance with SCIPlpiWasSolved() whether the LP is currently solved. If this is the case, you have to make sure, the internal solution status is recovered completely at the end of your method. This can be achieved by getting the LPI state before applying any LPI manipulations with SCIPlpiGetState() and restoring it afterwards with SCIPlpiSetState() and SCIPlpiFreeState(). Additionally you have to resolve the LP with the appropriate SCIPlpiSolve...() call in order to reinstall the internal solution status.; Make also sure, that all parameter values that you have changed are set back to their original values.

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
lpi	pointer to store the LP interface

Definition at line 896 of file scip_lp.c.

References FALSE, Scip::lp, NULL, SCIP_CALL, SCIP_OKAY, SCIPcheckStage(), SCIPlpGetLPI(), and TRUE.

Referenced by performStrongbranchWithPropagation(), SCIP_DECL_DISPOUTPUT(), selectVarRecursive(), and warmStartInfoIsReadable().

◆ SCIPprintLPSolutionQuality()

SCIP_EXPORT SCIP_RETCODE SCIPprintLPSolutionQuality	(	SCIP *	scip,
		FILE *	file
	)

Displays quality information about the current LP solution. An LP solution need to be available. Information printed is subject to what the LP solver supports

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Note: The printing process is done via the message handler system.

displays quality information about the current LP solution. An LP solution need to be available; information printed is subject to what the LP solver supports

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Note: The printing process is done via the message handler system.

Parameters

scip	SCIP data structure
file	output file (or NULL for standard output)

Definition at line 932 of file scip_lp.c.

References FALSE, Scip::lp, Scip::messagehdlr, NULL, SCIP_CALL, SCIP_INVALID, SCIP_INVALIDCALL, SCIP_LPSOLQUALITY_ESTIMCONDITION, SCIP_LPSOLQUALITY_EXACTCONDITION, SCIP_OKAY, SCIP_Real, SCIP_STAGE_EXITPRESOLVE, SCIP_STAGE_INIT, SCIP_STAGE_INITPRESOLVE, SCIP_STAGE_PRESOLVED, SCIP_STAGE_PRESOLVING, SCIP_STAGE_PROBLEM, SCIP_STAGE_SOLVED, SCIP_STAGE_SOLVING, SCIP_STAGE_TRANSFORMED, SCIPcheckStage(), SCIPerrorMessage, SCIPlpGetLPI(), SCIPlpiGetRealSolQuality(), SCIPmessageFPrintInfo(), Scip::set, SCIP_Set::stage, and TRUE.

Referenced by SCIP_DECL_DIALOGEXEC().

◆ SCIPcomputeLPRelIntPoint()

SCIP_EXPORT SCIP_RETCODE SCIPcomputeLPRelIntPoint	(	SCIP *	scip,
		SCIP_Bool	relaxrows,
		SCIP_Bool	inclobjcutoff,
		SCIP_Real	timelimit,
		int	iterlimit,
		SCIP_SOL **	point
	)

compute relative interior point to current LP

See also: SCIPlpComputeRelIntPoint

Returns: SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See SCIP_RETCODE for a complete list of error codes.

Precondition

This method can be called if scip is in one of the following stages:

See SCIP_STAGE for a complete list of all possible solving stages.

Parameters

scip	SCIP data structure
relaxrows	should the rows be relaxed
inclobjcutoff	should a row for the objective cutoff be included
timelimit	time limit for LP solver
iterlimit	iteration limit for LP solver
point	relative interior point on exit

Definition at line 1005 of file scip_lp.c.

References FALSE, Scip::lp, Scip::messagehdlr, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcheckStage(), SCIPcolGetVar(), SCIPcreateSol(), SCIPfreeBufferArray, SCIPlpComputeRelIntPoint(), SCIPlpGetCols(), SCIPlpGetNCols(), SCIPsetSolVal(), Scip::set, Scip::transprob, and TRUE.

Referenced by SCIP_DECL_SEPAEXECLP().

SCIP

Detailed Description

Modules

Functions

Function Documentation

◆ SCIPhasCurrentNodeLP()

◆ SCIPisLPConstructed()

◆ SCIPconstructLP()

◆ SCIPflushLP()

◆ SCIPgetLPSolstat()

◆ SCIPisLPPrimalReliable()

◆ SCIPisLPDualReliable()

◆ SCIPisLPRelax()

◆ SCIPgetLPObjval()

◆ SCIPgetLPColumnObjval()

◆ SCIPgetLPLooseObjval()

◆ SCIPgetGlobalPseudoObjval()

◆ SCIPgetPseudoObjval()

◆ SCIPisRootLPRelax()

◆ SCIPgetLPRootObjval()

◆ SCIPgetLPRootColumnObjval()

◆ SCIPgetLPRootLooseObjval()

◆ SCIPgetLPColsData()

◆ SCIPgetLPCols()

◆ SCIPgetNLPCols()

◆ SCIPgetLPRowsData()

◆ SCIPgetLPRows()

◆ SCIPgetNLPRows()

◆ SCIPallColsInLP()

◆ SCIPisLPSolBasic()

◆ SCIPgetLPBasisInd()

◆ SCIPgetLPBInvRow()

◆ SCIPgetLPBInvCol()

◆ SCIPgetLPBInvARow()

◆ SCIPgetLPBInvACol()

◆ SCIPsumLPRows()

◆ SCIPwriteLP()

◆ SCIPwriteMIP()

◆ SCIPgetLPI()

◆ SCIPprintLPSolutionQuality()

◆ SCIPcomputeLPRelIntPoint()