/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ /* */ /* This file is part of the program and library */ /* SCIP --- Solving Constraint Integer Programs */ /* */ /* Copyright 2002-2022 Zuse Institute Berlin */ /* */ /* Licensed under the Apache License, Version 2.0 (the "License"); */ /* you may not use this file except in compliance with the License. */ /* You may obtain a copy of the License at */ /* */ /* http://www.apache.org/licenses/LICENSE-2.0 */ /* */ /* Unless required by applicable law or agreed to in writing, software */ /* distributed under the License is distributed on an "AS IS" BASIS, */ /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */ /* See the License for the specific language governing permissions and */ /* limitations under the License. */ /* */ /* You should have received a copy of the Apache-2.0 license */ /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */ /* */ /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ /**@file branch.h * @ingroup INTERNALAPI * @brief internal methods for branching rules and branching candidate storage * @author Tobias Achterberg */ /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ #ifndef __SCIP_BRANCH_H__ #define __SCIP_BRANCH_H__ #include "blockmemshell/memory.h" #include "scip/def.h" #include "scip/type_branch.h" #include "scip/type_event.h" #include "scip/type_lp.h" #include "scip/type_message.h" #include "scip/type_prob.h" #include "scip/type_reopt.h" #include "scip/type_result.h" #include "scip/type_retcode.h" #include "scip/type_scip.h" #include "scip/type_sepastore.h" #include "scip/type_set.h" #include "scip/type_stat.h" #include "scip/type_tree.h" #include "scip/type_var.h" #ifdef __cplusplus extern "C" { #endif /* * branching candidate storage methods */ /** creates a branching candidate storage */ SCIP_RETCODE SCIPbranchcandCreate( SCIP_BRANCHCAND** branchcand /**< pointer to store branching candidate storage */ ); /** frees branching candidate storage */ SCIP_RETCODE SCIPbranchcandFree( SCIP_BRANCHCAND** branchcand /**< pointer to store branching candidate storage */ ); /** invalidates branching candidates storage */ void SCIPbranchcandInvalidate( SCIP_BRANCHCAND* branchcand /**< pointer to store branching candidate storage */ ); /** gets branching candidates for LP solution branching (fractional variables) */ SCIP_RETCODE SCIPbranchcandGetLPCands( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_LP* lp, /**< current LP data */ SCIP_VAR*** lpcands, /**< pointer to store the array of LP branching candidates, or NULL */ SCIP_Real** lpcandssol, /**< pointer to store the array of LP candidate solution values, or NULL */ SCIP_Real** lpcandsfrac, /**< pointer to store the array of LP candidate fractionalities, or NULL */ int* nlpcands, /**< pointer to store the number of LP branching candidates, or NULL */ int* npriolpcands, /**< pointer to store the number of candidates with maximal priority, or NULL */ int* nfracimplvars /**< pointer to store the number of implicit fractional variables, or NULL */ ); /** gets external branching candidates */ SCIP_RETCODE SCIPbranchcandGetExternCands( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_VAR*** externcands, /**< pointer to store the array of external branching candidates, or NULL */ SCIP_Real** externcandssol, /**< pointer to store the array of external candidate solution values, or NULL */ SCIP_Real** externcandsscore, /**< pointer to store the array of external candidate scores, or NULL */ int* nexterncands, /**< pointer to store the number of external branching candidates, or NULL */ int* nprioexterncands, /**< pointer to store the number of candidates with maximal priority, or NULL */ int* nprioexternbins, /**< pointer to store the number of binary candidates with maximal priority, or NULL */ int* nprioexternints, /**< pointer to store the number of integer candidates with maximal priority, or NULL */ int* nprioexternimpls /**< pointer to store the number of implicit integer candidates with maximal priority, * or NULL */ ); /** gets maximal branching priority of LP branching candidates */ int SCIPbranchcandGetLPMaxPrio( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of LP branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioLPCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets maximal branching priority of external branching candidates */ int SCIPbranchcandGetExternMaxPrio( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of external branching candidates */ int SCIPbranchcandGetNExternCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of external branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioExternCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of binary external branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioExternBins( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of integer external branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioExternInts( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of implicit integer external branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioExternImpls( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of continuous external branching candidates with maximal branch priority */ int SCIPbranchcandGetNPrioExternConts( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** insert variable, its score and its solution value into the external branching candidate storage * the absolute difference of the current lower and upper bounds of the variable must be at least epsilon */ SCIP_RETCODE SCIPbranchcandAddExternCand( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_SET* set, /**< global SCIP settings */ SCIP_VAR* var, /**< variable to insert */ SCIP_Real score, /**< score of external candidate, e.g. infeasibility */ SCIP_Real solval /**< value of the variable in the current solution */ ); /** removes all external candidates from the storage for external branching */ void SCIPbranchcandClearExternCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** checks whether the given variable is contained in the candidate storage for external branching */ SCIP_Bool SCIPbranchcandContainsExternCand( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_VAR* var /**< variable to look for */ ); /** gets branching candidates for pseudo solution branching (non-fixed variables) */ SCIP_RETCODE SCIPbranchcandGetPseudoCands( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_SET* set, /**< global SCIP settings */ SCIP_PROB* prob, /**< problem data */ SCIP_VAR*** pseudocands, /**< pointer to store the array of pseudo branching candidates, or NULL */ int* npseudocands, /**< pointer to store the number of pseudo branching candidates, or NULL */ int* npriopseudocands /**< pointer to store the number of candidates with maximal priority, or NULL */ ); /** gets number of branching candidates for pseudo solution branching (non-fixed variables) */ int SCIPbranchcandGetNPseudoCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of branching candidates with maximal branch priority for pseudo solution branching */ int SCIPbranchcandGetNPrioPseudoCands( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of binary branching candidates with maximal branch priority for pseudo solution branching */ int SCIPbranchcandGetNPrioPseudoBins( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of integer branching candidates with maximal branch priority for pseudo solution branching */ int SCIPbranchcandGetNPrioPseudoInts( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** gets number of implicit integer branching candidates with maximal branch priority for pseudo solution branching */ int SCIPbranchcandGetNPrioPseudoImpls( SCIP_BRANCHCAND* branchcand /**< branching candidate storage */ ); /** removes variable from branching candidate list */ SCIP_RETCODE SCIPbranchcandRemoveVar( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_VAR* var /**< variable that changed its bounds */ ); /** updates branching candidate list for a given variable */ SCIP_RETCODE SCIPbranchcandUpdateVar( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_SET* set, /**< global SCIP settings */ SCIP_VAR* var /**< variable that changed its bounds */ ); /** updates branching priority of the given variable and update the pseudo candidate array if needed */ SCIP_RETCODE SCIPbranchcandUpdateVarBranchPriority( SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_SET* set, /**< global SCIP settings */ SCIP_VAR* var, /**< variable that changed its bounds */ int branchpriority /**< branch priority of the variable */ ); /* * branching rules */ /** copies the given branchrule to a new scip */ SCIP_RETCODE SCIPbranchruleCopyInclude( SCIP_BRANCHRULE* branchrule, /**< branchrule */ SCIP_SET* set /**< SCIP_SET of SCIP to copy to */ ); /** creates a branching rule */ SCIP_RETCODE SCIPbranchruleCreate( SCIP_BRANCHRULE** branchrule, /**< pointer to store branching rule */ SCIP_SET* set, /**< global SCIP settings */ SCIP_MESSAGEHDLR* messagehdlr, /**< message handler */ BMS_BLKMEM* blkmem, /**< block memory for parameter settings */ const char* name, /**< name of branching rule */ const char* desc, /**< description of branching rule */ int priority, /**< priority of the branching rule */ int maxdepth, /**< maximal depth level, up to which this branching rule should be used (or -1) */ SCIP_Real maxbounddist, /**< maximal relative distance from current node's dual bound to primal bound * compared to best node's dual bound for applying branching rule * (0.0: only on current best node, 1.0: on all nodes) */ SCIP_DECL_BRANCHCOPY ((*branchcopy)), /**< copy method of branching rule */ SCIP_DECL_BRANCHFREE ((*branchfree)), /**< destructor of branching rule */ SCIP_DECL_BRANCHINIT ((*branchinit)), /**< initialize branching rule */ SCIP_DECL_BRANCHEXIT ((*branchexit)), /**< deinitialize branching rule */ SCIP_DECL_BRANCHINITSOL((*branchinitsol)),/**< solving process initialization method of branching rule */ SCIP_DECL_BRANCHEXITSOL((*branchexitsol)),/**< solving process deinitialization method of branching rule */ SCIP_DECL_BRANCHEXECLP((*branchexeclp)), /**< branching execution method for fractional LP solutions */ SCIP_DECL_BRANCHEXECEXT((*branchexecext)),/**< branching execution method for external solutions */ SCIP_DECL_BRANCHEXECPS((*branchexecps)), /**< branching execution method for not completely fixed pseudo solutions */ SCIP_BRANCHRULEDATA* branchruledata /**< branching rule data */ ); /** frees memory of branching rule */ SCIP_RETCODE SCIPbranchruleFree( SCIP_BRANCHRULE** branchrule, /**< pointer to branching rule data structure */ SCIP_SET* set /**< global SCIP settings */ ); /** initializes branching rule */ SCIP_RETCODE SCIPbranchruleInit( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set /**< global SCIP settings */ ); /** deinitializes branching rule */ SCIP_RETCODE SCIPbranchruleExit( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set /**< global SCIP settings */ ); /** informs branching rule that the branch and bound process is being started */ SCIP_RETCODE SCIPbranchruleInitsol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set /**< global SCIP settings */ ); /** informs branching rule that the branch and bound process data is being freed */ SCIP_RETCODE SCIPbranchruleExitsol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set /**< global SCIP settings */ ); /** executes branching rule for fractional LP solution */ SCIP_RETCODE SCIPbranchruleExecLPSol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_SEPASTORE* sepastore, /**< separation storage */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the callback method */ ); /** executes branching rule for external branching candidates */ SCIP_RETCODE SCIPbranchruleExecExternSol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_SEPASTORE* sepastore, /**< separation storage */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the callback method */ ); /** executes branching rule for not completely fixed pseudo solution */ SCIP_RETCODE SCIPbranchruleExecPseudoSol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the callback method */ ); /** sets priority of branching rule */ void SCIPbranchruleSetPriority( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_SET* set, /**< global SCIP settings */ int priority /**< new priority of the branching rule */ ); /** sets maximal depth level, up to which this branching rule should be used (-1 for no limit) */ void SCIPbranchruleSetMaxdepth( SCIP_BRANCHRULE* branchrule, /**< branching rule */ int maxdepth /**< new maxdepth of the branching rule */ ); /** sets maximal relative distance from current node's dual bound to primal bound for applying branching rule */ void SCIPbranchruleSetMaxbounddist( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_Real maxbounddist /**< new maxbounddist of the branching rule */ ); /** sets copy method of branching rule */ void SCIPbranchruleSetCopy( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHCOPY ((*branchcopy)) /**< copy method of branching rule or NULL if you don't want to copy your plugin into sub-SCIPs */ ); /** sets destructor method of branching rule */ void SCIPbranchruleSetFree( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHFREE ((*branchfree)) /**< destructor of branching rule */ ); /** sets initialization method of branching rule */ void SCIPbranchruleSetInit( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHINIT ((*branchinit)) /**< initialize branching rule */ ); /** sets deinitialization method of branching rule */ void SCIPbranchruleSetExit( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHEXIT ((*branchexit)) /**< deinitialize branching rule */ ); /** sets solving process initialization method of branching rule */ void SCIPbranchruleSetInitsol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHINITSOL((*branchinitsol)) /**< solving process initialization method of branching rule */ ); /** sets solving process deinitialization method of branching rule */ void SCIPbranchruleSetExitsol( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHEXITSOL((*branchexitsol)) /**< solving process deinitialization method of branching rule */ ); /** sets branching execution method for fractional LP solutions */ void SCIPbranchruleSetExecLp( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHEXECLP((*branchexeclp)) /**< branching execution method for fractional LP solutions */ ); /** sets branching execution method for external candidates */ void SCIPbranchruleSetExecExt( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHEXECEXT((*branchexecext)) /**< branching execution method for external candidates */ ); /** sets branching execution method for not completely fixed pseudo solutions */ void SCIPbranchruleSetExecPs( SCIP_BRANCHRULE* branchrule, /**< branching rule */ SCIP_DECL_BRANCHEXECPS((*branchexecps)) /**< branching execution method for not completely fixed pseudo solutions */ ); /** enables or disables all clocks of \p branchrule, depending on the value of the flag */ void SCIPbranchruleEnableOrDisableClocks( SCIP_BRANCHRULE* branchrule, /**< the branching rule for which all clocks should be enabled or disabled */ SCIP_Bool enable /**< should the clocks of the branching rule be enabled? */ ); /* * branching methods */ /** calculates the branching score out of the gain predictions for a binary branching */ SCIP_Real SCIPbranchGetScore( SCIP_SET* set, /**< global SCIP settings */ SCIP_VAR* var, /**< variable, of which the branching factor should be applied, or NULL */ SCIP_Real downgain, /**< prediction of objective gain for rounding downwards */ SCIP_Real upgain /**< prediction of objective gain for rounding upwards */ ); /** calculates the branching score out of the gain predictions for a branching with arbitrary many children */ SCIP_Real SCIPbranchGetScoreMultiple( SCIP_SET* set, /**< global SCIP settings */ SCIP_VAR* var, /**< variable, of which the branching factor should be applied, or NULL */ int nchildren, /**< number of children that the branching will create */ SCIP_Real* gains /**< prediction of objective gain for each child */ ); /** computes a branching point for a (not necessarily discrete) variable * a suggested branching point is first projected onto the box * if no point is suggested, then the value in the current LP or pseudo solution is used * if this value is at infinity, then 0.0 projected onto the bounds and then moved inside the interval is used * for a discrete variable, it is ensured that the returned value is fractional * for a continuous variable, the parameter branching/clamp defines how far a branching point need to be from the bounds of a variable * the latter is only applied if no point has been suggested, or the suggested point is not inside the variable's interval */ SCIP_Real SCIPbranchGetBranchingPoint( SCIP_SET* set, /**< global SCIP settings */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_VAR* var, /**< variable, of which the branching point should be computed */ SCIP_Real suggestion /**< suggestion for branching point, or SCIP_INVALID if no suggestion */ ); /** calls branching rules to branch on an LP solution; if no fractional variables exist, the result is SCIP_DIDNOTRUN; * if the branch priority of an unfixed variable is larger than the maximal branch priority of the fractional * variables, pseudo solution branching is applied on the unfixed variables with maximal branch priority */ SCIP_RETCODE SCIPbranchExecLP( BMS_BLKMEM* blkmem, /**< block memory for parameter settings */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_PROB* transprob, /**< transformed problem after presolve */ SCIP_PROB* origprob, /**< original problem */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_REOPT* reopt, /**< reoptimization data structure */ SCIP_LP* lp, /**< current LP data */ SCIP_SEPASTORE* sepastore, /**< separation storage */ SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_EVENTQUEUE* eventqueue, /**< event queue */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the branching */ ); /** calls branching rules to branch on an external solution; if no external branching candidates exist, the result is SCIP_DIDNOTRUN */ SCIP_RETCODE SCIPbranchExecExtern( BMS_BLKMEM* blkmem, /**< block memory for parameter settings */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_PROB* transprob, /**< transformed problem after presolve */ SCIP_PROB* origprob, /**< original problem */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_REOPT* reopt, /**< reoptimization data structure */ SCIP_LP* lp, /**< current LP data */ SCIP_SEPASTORE* sepastore, /**< separation storage */ SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_EVENTQUEUE* eventqueue, /**< event queue */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the branching */ ); /** calls branching rules to branch on a pseudo solution; if no unfixed variables exist, the result is SCIP_DIDNOTRUN */ SCIP_RETCODE SCIPbranchExecPseudo( BMS_BLKMEM* blkmem, /**< block memory for parameter settings */ SCIP_SET* set, /**< global SCIP settings */ SCIP_STAT* stat, /**< problem statistics */ SCIP_PROB* transprob, /**< transformed problem after presolve */ SCIP_PROB* origprob, /**< original problem */ SCIP_TREE* tree, /**< branch and bound tree */ SCIP_REOPT* reopt, /**< reoptimization data structure */ SCIP_LP* lp, /**< current LP data */ SCIP_BRANCHCAND* branchcand, /**< branching candidate storage */ SCIP_EVENTQUEUE* eventqueue, /**< event queue */ SCIP_Real cutoffbound, /**< global upper cutoff bound */ SCIP_Bool allowaddcons, /**< should adding constraints be allowed to avoid a branching? */ SCIP_RESULT* result /**< pointer to store the result of the branching */ ); #ifdef __cplusplus } #endif #endif