methods and files provided by the default branching rules of SCIP
A detailed description what a branching rule does and how to add a branching rule to SCIP can be found here.
Modules | |
Inclusion methods | |
methods to include specific branching rules into SCIP | |
Functions | |
void | SCIPvarCalcDistributionParameters (SCIP *scip, SCIP_Real varlb, SCIP_Real varub, SCIP_VARTYPE vartype, SCIP_Real *mean, SCIP_Real *variance) |
SCIP_Real | SCIPcalcCumulativeDistribution (SCIP *scip, SCIP_Real mean, SCIP_Real variance, SCIP_Real value) |
SCIP_Real | SCIProwCalcProbability (SCIP *scip, SCIP_ROW *row, SCIP_Real mu, SCIP_Real sigma2, int rowinfinitiesdown, int rowinfinitiesup) |
SCIP_RETCODE | SCIPupdateDistributionScore (SCIP *scip, SCIP_Real currentprob, SCIP_Real newprobup, SCIP_Real newprobdown, SCIP_Real *upscore, SCIP_Real *downscore, char scoreparam) |
SCIP_RETCODE | SCIPselectVarStrongBranching (SCIP *scip, SCIP_VAR **lpcands, SCIP_Real *lpcandssol, SCIP_Real *lpcandsfrac, SCIP_Bool *skipdown, SCIP_Bool *skipup, int nlpcands, int npriolpcands, int ncomplete, int *start, SCIP_Bool allowaddcons, int maxproprounds, SCIP_Bool probingbounds, SCIP_Bool forcestrongbranch, int *bestcand, SCIP_Real *bestdown, SCIP_Real *bestup, SCIP_Real *bestscore, SCIP_Bool *bestdownvalid, SCIP_Bool *bestupvalid, SCIP_Real *provedbound, SCIP_RESULT *result) |
SCIP_RETCODE | SCIPselectBranchVarPscost (SCIP *scip, SCIP_VAR **branchcands, SCIP_Real *branchcandssol, SCIP_Real *branchcandsscore, int nbranchcands, SCIP_VAR **var, SCIP_Real *brpoint) |
SCIP_RETCODE | SCIPexecRelpscostBranching (SCIP *scip, SCIP_Bool allowaddcons, SCIP_VAR **branchcands, SCIP_Real *branchcandssol, SCIP_Real *branchcandsfrac, int nbranchcands, SCIP_Bool executebranching, SCIP_RESULT *result) |
Files | |
file | branch_allfullstrong.h |
all variables full strong LP branching rule | |
file | branch_cloud.h |
cloud branching rule | |
file | branch_distribution.c |
probability based branching rule based on an article by J. Pryor and J.W. Chinneck | |
file | branch_distribution.h |
probability based branching rule based on an article by J. Pryor and J.W. Chinneck | |
file | branch_fullstrong.h |
full strong LP branching rule | |
file | branch_inference.h |
inference history branching rule | |
file | branch_leastinf.h |
least infeasible LP branching rule | |
file | branch_mostinf.h |
most infeasible LP branching rule | |
file | branch_multaggr.h |
fullstrong branching on fractional and multi-aggregated variables | |
file | branch_nodereopt.h |
nodereopt branching rule | |
file | branch_pscost.h |
pseudo costs branching rule | |
file | branch_random.h |
random variable branching rule | |
file | branch_relpscost.h |
reliable pseudo costs branching rule | |
file | branch_ryanfoster.c |
Ryan/Foster branching rule. | |
void SCIPvarCalcDistributionParameters | ( | SCIP * | scip, |
SCIP_Real | varlb, | ||
SCIP_Real | varub, | ||
SCIP_VARTYPE | vartype, | ||
SCIP_Real * | mean, | ||
SCIP_Real * | variance | ||
) |
calculate the variable's distribution parameters (mean and variance) for the bounds specified in the arguments. special treatment of infinite bounds necessary
scip | SCIP data structure |
varlb | variable lower bound |
varub | variable upper bound |
vartype | type of the variable |
mean | pointer to store mean value |
variance | pointer to store the variance of the variable uniform distribution |
Definition at line 235 of file branch_distribution.c.
References NULL, SCIP_VARTYPE_CONTINUOUS, SCIPisInfinity(), SCIPisNegative(), and SQUARED.
Referenced by calcBranchScore(), rowCalculateGauss(), and varProcessBoundChanges().
SCIP_Real SCIPcalcCumulativeDistribution | ( | SCIP * | scip, |
SCIP_Real | mean, | ||
SCIP_Real | variance, | ||
SCIP_Real | value | ||
) |
calculates the cumulative distribution P(-infinity <= x <= value) that a normally distributed random variable x takes a value between -infinity and parameter value
.
The distribution is given by the respective mean and deviation. This implementation uses the error function erf().
calculates the cumulative distribution P(-infinity <= x <= value) that a normally distributed random variable x takes a value between -infinity and parameter value
.
The distribution is given by the respective mean and deviation. This implementation uses the error function SCIPerf().
scip | current SCIP |
mean | the mean value of the distribution |
variance | the square of the deviation of the distribution |
value | the upper limit of the calculated distribution integral |
Definition at line 280 of file branch_distribution.c.
References SCIP_Real, SCIPdebugMsg, SCIPerf(), SCIPisFeasLE(), SCIPisFeasZero(), SCIPisNegative(), sqrt(), and SQRTOFTWO.
Referenced by SCIProwCalcProbability().
SCIP_Real SCIProwCalcProbability | ( | SCIP * | scip, |
SCIP_ROW * | row, | ||
SCIP_Real | mu, | ||
SCIP_Real | sigma2, | ||
int | rowinfinitiesdown, | ||
int | rowinfinitiesup | ||
) |
calculates the probability of satisfying an LP-row under the assumption of uniformly distributed variable values.
For inequalities, we use the cumulative distribution function of the standard normal distribution PHI(rhs - mu/sqrt(sigma2)) to calculate the probability for a right hand side row with mean activity mu and variance sigma2 to be satisfied. Similarly, 1 - PHI(lhs - mu/sqrt(sigma2)) is the probability to satisfy a left hand side row. For equations (lhs==rhs), we use the centeredness measure p = min(PHI(lhs'), 1-PHI(lhs'))/max(PHI(lhs'), 1 - PHI(lhs')), where lhs' = lhs - mu / sqrt(sigma2).
scip | current scip |
row | the row |
mu | the mean value of the row distribution |
sigma2 | the variance of the row distribution |
rowinfinitiesdown | the number of variables with infinite bounds to DECREASE activity |
rowinfinitiesup | the number of variables with infinite bounds to INCREASE activity |
Definition at line 344 of file branch_distribution.c.
References MAX, MIN, NULL, SCIP_Real, SCIPcalcCumulativeDistribution(), SCIPdebug, SCIPdebugMsg, SCIPisFeasEQ(), SCIPisFeasGE(), SCIPisFeasLE(), SCIPisInfinity(), SCIPprintRow(), SCIProwGetLhs(), SCIProwGetName(), and SCIProwGetRhs().
Referenced by calcBranchScore().
SCIP_RETCODE SCIPupdateDistributionScore | ( | SCIP * | scip, |
SCIP_Real | currentprob, | ||
SCIP_Real | newprobup, | ||
SCIP_Real | newprobdown, | ||
SCIP_Real * | upscore, | ||
SCIP_Real * | downscore, | ||
char | scoreparam | ||
) |
update the up- and downscore of a single variable after calculating the impact of branching on a particular row, depending on the chosen score parameter
scip | current SCIP pointer |
currentprob | the current probability |
newprobup | the new probability if branched upwards |
newprobdown | the new probability if branched downwards |
upscore | pointer to store the new score for branching up |
downscore | pointer to store the new score for branching down |
scoreparam | parameter to determine the way the score is calculated |
Definition at line 524 of file branch_distribution.c.
References NULL, SCIP_INVALIDCALL, SCIP_OKAY, SCIPerrorMessage, SCIPisFeasGE(), SCIPisFeasLE(), SCIPisGT(), and SCIPisLT().
Referenced by calcBranchScore().
SCIP_RETCODE SCIPselectVarStrongBranching | ( | SCIP * | scip, |
SCIP_VAR ** | lpcands, | ||
SCIP_Real * | lpcandssol, | ||
SCIP_Real * | lpcandsfrac, | ||
SCIP_Bool * | skipdown, | ||
SCIP_Bool * | skipup, | ||
int | nlpcands, | ||
int | npriolpcands, | ||
int | ncomplete, | ||
int * | start, | ||
SCIP_Bool | allowaddcons, | ||
int | maxproprounds, | ||
SCIP_Bool | probingbounds, | ||
SCIP_Bool | forcestrongbranch, | ||
int * | bestcand, | ||
SCIP_Real * | bestdown, | ||
SCIP_Real * | bestup, | ||
SCIP_Real * | bestscore, | ||
SCIP_Bool * | bestdownvalid, | ||
SCIP_Bool * | bestupvalid, | ||
SCIP_Real * | provedbound, | ||
SCIP_RESULT * | result | ||
) |
Selects a variable from a set of candidates by strong branching
scip | original SCIP data structure |
lpcands | branching candidates |
lpcandssol | solution values of the branching candidates |
lpcandsfrac | fractional values of the branching candidates |
skipdown | should down branchings be skipped? |
skipup | should up branchings be skipped? |
nlpcands | number of branching candidates |
npriolpcands | number of priority branching candidates |
ncomplete | number of branching candidates without skip |
start | starting index in lpcands |
allowaddcons | is the branching rule allowed to add constraints? |
maxproprounds | maximum number of propagation rounds to be performed during strong branching before solving the LP (-1: no limit, -2: parameter settings) |
probingbounds | should valid bounds be identified in a probing-like fashion during strong branching (only with propagation)? |
forcestrongbranch | should strong branching be applied even if there is just a single candidate? |
bestcand | best candidate for branching |
bestdown | objective value of the down branch for bestcand |
bestup | objective value of the up branch for bestcand |
bestscore | score for bestcand |
bestdownvalid | is bestdown a valid dual bound for the down branch? |
bestupvalid | is bestup a valid dual bound for the up branch? |
provedbound | proved dual bound for current subtree |
result | result pointer |
Definition at line 149 of file branch_fullstrong.c.
References BRANCHRULE_NAME, FALSE, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_CONSADDED, SCIP_CUTOFF, SCIP_DECL_BRANCHEXECLP(), SCIP_Longint, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIP_Real, SCIP_REDUCEDDOM, SCIP_VERBLEVEL_HIGH, SCIPallColsInLP(), SCIPallocBufferArray, SCIPbranchruleGetData(), SCIPchgVarLb(), SCIPchgVarUb(), SCIPdebug, SCIPdebugMsg, SCIPendStrongbranch(), SCIPfeasCeil(), SCIPfeasFloor(), SCIPfindBranchrule(), SCIPfreeBufferArray, SCIPgetBranchScore(), SCIPgetCutoffbound(), SCIPgetDepth(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetNNodes(), SCIPgetNVars(), SCIPgetVars(), SCIPgetVarStrongbranchFrac(), SCIPgetVarStrongbranchLast(), SCIPgetVarStrongbranchLPAge(), SCIPgetVarStrongbranchNode(), SCIPgetVarStrongbranchWithPropagation(), SCIPinfinity(), SCIPisExactSolve(), SCIPisFeasZero(), SCIPisGE(), SCIPisGT(), SCIPisLT(), SCIPisStopped(), SCIPprintDisplayLine(), SCIPstartStrongbranch(), SCIPtightenVarLb(), SCIPtightenVarUb(), SCIPupdateVarPseudocost(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetUbLocal(), SCIPverbMessage(), and TRUE.
Referenced by SCIP_DECL_BRANCHEXECLP().
SCIP_RETCODE SCIPselectBranchVarPscost | ( | SCIP * | scip, |
SCIP_VAR ** | branchcands, | ||
SCIP_Real * | branchcandssol, | ||
SCIP_Real * | branchcandsscore, | ||
int | nbranchcands, | ||
SCIP_VAR ** | var, | ||
SCIP_Real * | brpoint | ||
) |
selects a branching variable, due to pseudo cost, from the given candidate array and returns this variable together with a branching point
scip | SCIP data structure |
branchcands | branching candidates |
branchcandssol | solution value for the branching candidates |
branchcandsscore | array of candidate scores |
nbranchcands | number of branching candidates |
var | pointer to store the variable to branch on, or NULL if none |
brpoint | pointer to store the branching point for the branching variable, will be fractional for a discrete variable |
Definition at line 806 of file branch_pscost.c.
References BRANCHRULE_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPfindBranchrule(), and selectBranchVar().
SCIP_RETCODE SCIPexecRelpscostBranching | ( | SCIP * | scip, |
SCIP_Bool | allowaddcons, | ||
SCIP_VAR ** | branchcands, | ||
SCIP_Real * | branchcandssol, | ||
SCIP_Real * | branchcandsfrac, | ||
int | nbranchcands, | ||
SCIP_Bool | executebranching, | ||
SCIP_RESULT * | result | ||
) |
execution reliability pseudo cost branching with the given branching candidates
scip | SCIP data structure |
allowaddcons | is the branching rule allowed to add constraints to the current node in order to cut off the current solution instead of creating a branching? |
branchcands | branching candidates |
branchcandssol | solution value for the branching candidates |
branchcandsfrac | fractional part of the branching candidates |
nbranchcands | number of branching candidates |
executebranching | perform a branching step after probing |
result | pointer to the result of the execution |
Definition at line 1719 of file branch_relpscost.c.
References BRANCHRULE_NAME, execRelpscost(), NULL, SCIP_CALL, SCIP_OKAY, and SCIPfindBranchrule().
Referenced by SCIP_DECL_BRANCHEXECLP(), and SCIPincludeBranchruleRelpscost().