Detailed Description

methods to control the solving process of SCIP

This large group of methods and modules comprises the solving process related API of SCIP. This includes

changing parameters to control the solver behavior
access search tree related information
access relaxation information
access various solving process statistics
solve auxiliary relaxations and subproblems using LP/NLP diving or probing mode

Topics
	Solving Statistics
	methods to query statistics about the solving process
	Parameter
	methods to create, query, and print user parameters
	Event Handling
	methods to create, catch, process, and drop events during the solving process of SCIP
	LP Relaxation
	methods to build and access LP relaxation information
	Exact LP Relaxation
	methods to manage exact LP relaxation
	Exact Solving Mode
	general methods for numerically exact solving
	Certificate Output
	methods for certified solving
	NLP Relaxation
	methods for the nonlinear relaxation
	Conflict Analysis
	public methods for conflict analysis
	Branching
	methods for branching on LP solutions, relaxation solutions, and pseudo solutions
	Local Subproblem
	methods to query information about or strengthen the problem at the current local search node
	Search Tree
	methods to query search tree related information
	Probing
	methods to initiate and control the probing mode of SCIP
	Reoptimization
	methods for reoptimization related tasks

Functions
SCIP_RETCODE	SCIPtransformProb (SCIP *scip)
SCIP_RETCODE	SCIPpresolve (SCIP *scip)
SCIP_RETCODE	SCIPsolve (SCIP *scip)
SCIP_RETCODE	SCIPsolveConcurrent (SCIP *scip)
SCIP_RETCODE	SCIPfreeSolve (SCIP *scip, SCIP_Bool restart)
SCIP_RETCODE	SCIPfreeTransform (SCIP *scip)
SCIP_RETCODE	SCIPinterruptSolve (SCIP *scip)
SCIP_Bool	SCIPisSolveInterrupted (SCIP *scip)
SCIP_RETCODE	SCIPrestartSolve (SCIP *scip)
SCIP_Bool	SCIPisInRestart (SCIP *scip)

Function Documentation

◆ SCIPtransformProb()

SCIP_RETCODE SCIPtransformProb ( SCIP * scip )

initializes solving data structures and transforms problem

Before SCIP 10, this function also called the garbage collection for block memory explicitly. It has been removed for performance reason, but if memory is very tight, then the previous behavior can be restored by adding a call to SCIPcollectMemoryGarbage() before SCIPtransformProb().

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:

Postcondition: When calling this method in the SCIP_STAGE_PROBLEM stage, the SCIP stage is changed to SCIP_STAGE_TRANSFORMED; otherwise, the stage is not changed

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

Parameters

scip	SCIP data structure

Definition at line 232 of file scip_solve.c.

References assert(), calcNonZeros(), FALSE, h, MAX, NULL, REALABS, SCIP_Bool, SCIP_CALL, SCIP_Longint, SCIP_LONGINT_FORMAT, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STAGE_TRANSFORMED, SCIP_STAGE_TRANSFORMING, SCIP_STATUS_UNKNOWN, SCIP_VERBLEVEL_FULL, SCIP_VERBLEVEL_HIGH, SCIPblkmem(), SCIPbranchcandCreate(), SCIPcheckStage, SCIPcliquetableCreate(), SCIPconflictCreate(), SCIPconshdlrGetNActiveConss(), SCIPconshdlrGetName(), SCIPdebugMsg, SCIPerrorMessage, SCIPeventfilterCreate(), SCIPeventqueueCreate(), SCIPgetBestSol(), SCIPgetNConss(), SCIPgetNVars(), SCIPgetPrimalbound(), SCIPisExact(), SCIPisInfinity(), SCIPlpCreate(), SCIPlpExactCreate(), SCIPmessagePrintVerbInfo(), SCIPpermuteProb(), SCIPprimalAddSol(), SCIPprimalCreate(), SCIPprimalUpdateObjlimit(), SCIPprobCheckObjIntegral(), SCIPprobGetName(), SCIPprobGetNImplVars(), SCIPprobMarkNConss(), SCIPprobScaleObj(), SCIPprobTransform(), SCIPrationalCreateBlock(), SCIPrationalSetInfinity(), SCIPrelaxationCreate(), SCIPsetCheckParamValuePtrUnique(), SCIPsetGetNodesel(), SCIPsetInitPlugins(), SCIPsolCheckOrig(), SCIPsolFree(), SCIPsolGetObj(), SCIPsolRecomputeObj(), SCIPstatMark(), SCIPstoreSolutionGap(), SCIPtreeCreate(), sol, and TRUE.

Referenced by componentSetupWorkingSol(), createSubSCIP(), executeLNSHeuristic(), reoptimize(), reoptimize(), SCIP_DECL_DIALOGEXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_RELAXEXEC(), SCIPapplyHeurSubNlp(), SCIPapplyProximity(), SCIPpresolve(), SCIPsolveConcurrent(), setupAndSolve(), setupAndSolve(), setupAndSolveSubscip(), setupAndSolveSubscipCrossover(), setupAndSolveSubscipLocalbranching(), setupAndSolveSubscipOneopt(), setupAndSolveSubscipRapidlearning(), setupAndSolveSubscipTrustregion(), solveSubscip(), solveSubscipLpface(), wrapperDins(), and wrapperRins().

◆ SCIPpresolve()

SCIP_RETCODE SCIPpresolve ( SCIP * scip )

transforms and presolves problem

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:

Postcondition

After calling this method SCIP reaches one of the following stages:

SCIP_STAGE_PRESOLVING if the presolving process was interrupted
SCIP_STAGE_PRESOLVED if the presolving process was finished and did not solve the problem
SCIP_STAGE_SOLVED if the problem was solved during presolving

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

Parameters

scip	SCIP data structure

Definition at line 2449 of file scip_solve.c.

References assert(), displayRelevantStats(), FALSE, h, hasPresolveModifiedProblem(), initSolve(), NULL, presolve(), SCIP_Bool, SCIP_CALL, SCIP_ERROR, SCIP_INVALIDCALL, SCIP_OKAY, SCIP_STAGE_PRESOLVED, SCIP_STAGE_PRESOLVING, SCIP_STAGE_PROBLEM, SCIP_STAGE_SOLVED, SCIP_STAGE_TRANSFORMED, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_OPTIMAL, SCIP_STATUS_UNBOUNDED, SCIP_VERBLEVEL_DIALOG, SCIP_VERBLEVEL_HIGH, SCIP_VERBLEVEL_NORMAL, SCIPABORT, SCIPcheckStage, SCIPclockGetTime(), SCIPclockStart(), SCIPclockStop(), SCIPconshdlrGetNActiveConss(), SCIPconshdlrGetName(), SCIPerrorMessage, SCIPinterruptCapture(), SCIPinterruptLP(), SCIPinterruptRelease(), SCIPmessagePrintVerbInfo(), SCIPprobIsObjIntegral(), SCIPrationalPrintVerbInfo(), SCIPtransformProb(), SCIPtreeClear(), SCIPwarningMessage(), and TRUE.

Referenced by createSubSCIP(), executeLNSHeuristic(), fromCommandLine(), runGastrans(), runSpring(), SCIP_DECL_DIALOGEXEC(), SCIP_DECL_DIALOGEXEC(), SCIP_DECL_DIALOGEXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_RELAXEXEC(), SCIPapplyHeurDualval(), SCIPapplyProximity(), SCIPsolve(), SCIPsolveConcurrent(), setupAndSolve(), setupAndSolve(), setupAndSolveSubscip(), setupAndSolveSubscipRapidlearning(), and solveSubNLP().

◆ SCIPsolve()

SCIP_RETCODE SCIPsolve ( SCIP * scip )

transforms, presolves, and solves problem

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:

Postcondition: After calling this method SCIP reaches one of the following stages depending on if and when the solution process was interrupted:

SCIP_STAGE_PRESOLVING if the solution process was interrupted during presolving
SCIP_STAGE_SOLVING if the solution process was interrupted during the tree search
SCIP_STAGE_SOLVED if the solving process was not interrupted

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

Parameters

scip	SCIP data structure

Definition at line 2635 of file scip_solve.c.

References assert(), displayRelevantStats(), FALSE, freeSolve(), initSolve(), MAX, MIN, NULL, prepareReoptimization(), SCIP_Bool, SCIP_CALL, SCIP_INVALIDCALL, SCIP_Longint, SCIP_LONGINT_FORMAT, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STAGE_PRESOLVED, SCIP_STAGE_PRESOLVING, SCIP_STAGE_PROBLEM, SCIP_STAGE_SOLVED, SCIP_STAGE_SOLVING, SCIP_STAGE_TRANSFORMED, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_OPTIMAL, SCIP_STATUS_UNBOUNDED, SCIP_VERBLEVEL_NORMAL, SCIPcertificateSaveFinalbound(), SCIPcheckStage, SCIPclearRelaxSolVals(), SCIPclockStart(), SCIPclockStop(), SCIPcutpoolAddMaxNCuts(), SCIPcutpoolAddNCalls(), SCIPcutpoolAddNCutsAdded(), SCIPcutpoolAddNCutsFound(), SCIPcutpoolAddNRootCalls(), SCIPcutpoolGetMaxNCuts(), SCIPcutpoolGetNCalls(), SCIPcutpoolGetNCutsAdded(), SCIPcutpoolGetNCutsFound(), SCIPcutpoolGetNRootCalls(), SCIPcutpoolGetTime(), SCIPcutpoolSetTime(), SCIPdebug, SCIPdebugMsg, SCIPerrorMessage, SCIPfindConshdlr(), SCIPgetCertificate(), SCIPgetChildren(), SCIPgetLeaves(), SCIPgetNBinVars(), SCIPgetNIntVars(), SCIPgetNNodesLeft(), SCIPgetRealParam(), SCIPgetSiblings(), SCIPgetSolvingTime(), SCIPinfoMessage(), SCIPinterruptCapture(), SCIPinterruptLP(), SCIPinterruptRelease(), SCIPisExact(), SCIPmessagePrintVerbInfo(), SCIPpresolve(), SCIPreoptAddOptSol(), SCIPreoptAddSol(), SCIPreoptSaveOpenNodes(), SCIPreoptUpdateVarHistory(), SCIPsetGetNodesel(), SCIPsetRealParam(), SCIPsolGetHeur(), SCIPsolGetNodenum(), SCIPsolIsOriginal(), SCIPsolPrint(), SCIPsolRetransform(), SCIPsolveCIP(), SCIPsolveIsStopped(), SCIPstatResetDisplay(), SCIPtreeGetCurrentNode(), SCIPtreeGetNNodes(), SCIPverbMessage(), SCIPwarningMessage(), sol, and TRUE.

◆ SCIPsolveConcurrent()

SCIP_RETCODE SCIPsolveConcurrent ( SCIP * scip )

transforms, presolves, and solves problem using the configured concurrent solvers

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:

Postcondition

After calling this method SCIP reaches one of the following stages depending on if and when the solution process was interrupted:

SCIP_STAGE_PRESOLVING if the solution process was interrupted during presolving
SCIP_STAGE_SOLVING if the solution process was interrupted during the tree search
SCIP_STAGE_SOLVED if the solving process was not interrupted

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

Parameters

scip	SCIP data structure

Definition at line 2961 of file scip_solve.c.

References assert(), displayRelevantStats(), exitPresolve(), FALSE, i, initPresolve(), initSolve(), MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_CLOCKTYPE_WALL, SCIP_INVALIDDATA, SCIP_Longint, SCIP_MEM_NOLIMIT, SCIP_NOTIMPLEMENTED, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STAGE_PRESOLVED, SCIP_STATUS_MEMLIMIT, SCIP_STATUS_UNKNOWN, SCIP_VERBLEVEL_FULL, SCIPallocBufferArray, SCIPcheckStage, SCIPclockStart(), SCIPclockStop(), SCIPconcsolverCreateInstance(), SCIPconcsolverInitSeeds(), SCIPconcsolverTypeGetPrefPrio(), SCIPconcurrentSolve(), SCIPcreateRandom(), SCIPerrorMessage, SCIPfreeBufferArray, SCIPfreeConcurrent(), SCIPfreeRandom(), SCIPgetConcsolverTypes(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNConcsolverTypes(), SCIPgetNConcurrentSolvers(), SCIPgetStage(), SCIPgetStatus(), SCIPgetSyncstore(), SCIPisExact(), SCIPpresolve(), SCIPrandomGetInt(), SCIPselectDownRealInt(), SCIPsetIntParam(), SCIPsolve(), SCIPsyncstoreInit(), SCIPsyncstoreSetSolveIsStopped(), SCIPtpiIsAvailable(), SCIPtransformProb(), SCIPverbMessage(), SCIPwarningMessage(), and TRUE.

Referenced by SCIP_DECL_DIALOGEXEC().

◆ SCIPfreeSolve()

SCIP_RETCODE SCIPfreeSolve	(	SCIP *	scip,
		SCIP_Bool	restart )

frees branch and bound tree and all solution process data; statistics, presolving data and transformed problem is preserved

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:

Postcondition: If this method is called in SCIP stage SCIP_STAGE_INIT or SCIP_STAGE_PROBLEM, the stage of SCIP is not changed; otherwise, the SCIP stage is changed to SCIP_STAGE_TRANSFORMED

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

Parameters

scip	SCIP data structure
restart	should certain data be preserved for improved restarting?

Definition at line 3331 of file scip_solve.c.

References assert(), exitPresolve(), FALSE, freeSolve(), SCIP_Bool, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIP_STAGE_INIT, SCIP_STAGE_PRESOLVED, SCIP_STAGE_PRESOLVING, SCIP_STAGE_PROBLEM, SCIP_STAGE_SOLVED, SCIP_STAGE_SOLVING, SCIP_STAGE_TRANSFORMED, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_OPTIMAL, SCIP_STATUS_UNBOUNDED, SCIPcertificateIsEnabled(), SCIPcheckStage, SCIPerrorMessage, SCIPgetCertificate(), and TRUE.

Referenced by SCIP_DECL_DIALOGEXEC(), and SCIPfreeTransform().

◆ SCIPfreeTransform()

SCIP_RETCODE SCIPfreeTransform ( SCIP * scip )

frees all solution process data including presolving and transformed problem, only original problem is kept

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:

Postcondition

After calling this method SCIP reaches one of the following stages:

SCIP_STAGE_INIT if the method was called from SCIP stage SCIP_STAGE_INIT
SCIP_STAGE_PROBLEM if the method was called from any other of the allowed stages

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

Parameters

scip	SCIP data structure

Definition at line 3462 of file scip_solve.c.

References assert(), exitPresolve(), FALSE, freeTransform(), freeTransforming(), NULL, SCIP_Bool, SCIP_CALL, SCIP_INVALIDCALL, SCIP_OKAY, SCIP_STAGE_INIT, SCIP_STAGE_PRESOLVED, SCIP_STAGE_PRESOLVING, SCIP_STAGE_PROBLEM, SCIP_STAGE_SOLVED, SCIP_STAGE_SOLVING, SCIP_STAGE_TRANSFORMED, SCIP_STAGE_TRANSFORMING, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_OPTIMAL, SCIP_STATUS_UNBOUNDED, SCIPcheckStage, SCIPerrorMessage, SCIPfreeSolve(), SCIPreoptReleaseData(), and TRUE.

Referenced by additionFilterBatch(), deletionFilterBatch(), deletionSubproblem(), freeMemory(), readDiffFile(), reoptimize(), runBenders(), SCIP_DECL_DIALOGEXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXEC(), SCIP_DECL_READERREAD(), SCIPapplyHeurDualval(), SCIPapplyHeurSubNlp(), SCIPapplyProximity(), SCIPapplyUndercover(), SCIPbendersFreeSubproblem(), SCIPfreeProb(), SCIPiisGenerate(), solveAndEvalSubscip(), and updateMIP().

◆ SCIPinterruptSolve()

SCIP_RETCODE SCIPinterruptSolve ( SCIP * scip )

informs SCIP that the solving process should be interrupted as soon as possible (e.g., after the current node has been solved)

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:

Note: the SCIP stage does not get changed

Parameters

scip	SCIP data structure

Definition at line 3548 of file scip_solve.c.

References FALSE, SCIP_CALL, SCIP_OKAY, SCIPcheckStage, and TRUE.

Referenced by applySolvingPhase(), checkSolution(), SCIP_DECL_CONCSOLVERSTOP(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_RELAXEXEC(), and solveComponent().

◆ SCIPisSolveInterrupted()

SCIP_Bool SCIPisSolveInterrupted ( SCIP * scip )

indicates whether SCIP has been informed that the solving process should be interrupted as soon as possible

This function returns whether SCIPinterruptSolve() has been called, which is different from SCIPinterrupted(), which returns whether a SIGINT signal has been received by the SCIP signal handler.

Precondition

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

Note: the SCIP stage does not get changed

Parameters

scip	SCIP data structure

Definition at line 3580 of file scip_solve.c.

References FALSE, SCIP_Bool, SCIP_CALL_ABORT, SCIPcheckStage, and TRUE.

Referenced by F77_FUNC(), processSolveOutcome(), SCIP_DECL_NLPISOLVE(), and SCIP_DECL_NLPISOLVE().

◆ SCIPrestartSolve()

SCIP_RETCODE SCIPrestartSolve ( SCIP * scip )

informs SCIP that the solving process should be restarted as soon as possible (e.g., after the current node has been solved)

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:

Note: the SCIP stage does not get changed

Parameters

scip	SCIP data structure

Definition at line 3603 of file scip_solve.c.

References FALSE, SCIP_CALL, SCIP_OKAY, SCIPcheckStage, and TRUE.

Referenced by applySolvingPhase(), SCIP_DECL_CONSINITLP(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EVENTEXEC(), and SCIPbendersSolveSubproblemCIP().

◆ SCIPisInRestart()

SCIP_Bool SCIPisInRestart ( SCIP * scip )

returns whether we are in the restarting phase

Returns: TRUE, if we are in the restarting phase; FALSE, otherwise

Precondition

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

Parameters

scip	SCIP data structure

Definition at line 3709 of file scip_solve.c.

References FALSE, SCIP_Bool, SCIP_CALL_ABORT, SCIPcheckStage, and TRUE.

Referenced by copyCuts(), DECL_TIMESERIESUPDATE(), SCIP_DECL_PROPEXITSOL(), SCIPcertificatePrintResult(), SCIPconflictstoreClean(), and updateTreeData().

Detailed Description

Topics

Functions

Function Documentation

◆ SCIPtransformProb()

◆ SCIPpresolve()

◆ SCIPsolve()

◆ SCIPsolveConcurrent()

◆ SCIPfreeSolve()

◆ SCIPfreeTransform()

◆ SCIPinterruptSolve()

◆ SCIPisSolveInterrupted()

◆ SCIPrestartSolve()

◆ SCIPisInRestart()