propagator using the LP reduced cost and the cutoff bound
This propagator uses the reduced cost of an optimal solved LP relaxation to propagate the variables against the cutoff bound.
Definition in file prop_redcost.c.
Go to the source code of this file.
Macros | |
Propagator properties | |
#define | PROP_NAME "redcost" |
#define | PROP_DESC "reduced cost strengthening propagator" |
#define | PROP_TIMING SCIP_PROPTIMING_DURINGLPLOOP | SCIP_PROPTIMING_AFTERLPLOOP |
#define | PROP_PRIORITY +1000000 |
#define | PROP_FREQ 1 |
#define | PROP_DELAY FALSE |
Default parameter values | |
#define | DEFAULT_CONTINUOUS FALSE |
#define | DEFAULT_USEIMPLICS TRUE |
#define | DEFAULT_FORCE FALSE |
Functions | |
Local methods | |
static SCIP_RETCODE | propagateRootRedcostBinvar (SCIP *scip, SCIP_PROPDATA *propdata, SCIP_VAR *var, SCIP_COL *col, SCIP_Real cutoffbound, int *nchgbds) |
static SCIP_RETCODE | propagateRedcostBinvar (SCIP *scip, SCIP_PROPDATA *propdata, SCIP_VAR *var, SCIP_COL *col, SCIP_Real requiredredcost, int *nchgbds, SCIP_Bool *cutoff) |
static SCIP_RETCODE | propagateRedcostVar (SCIP *scip, SCIP_VAR *var, SCIP_COL *col, SCIP_Real lpobjval, SCIP_Real cutoffbound, int *nchgbds) |
Callback methods of propagator | |
static | SCIP_DECL_PROPCOPY (propCopyRedcost) |
static | SCIP_DECL_PROPFREE (propFreeRedcost) |
static | SCIP_DECL_PROPINITSOL (propInitsolRedcost) |
static | SCIP_DECL_PROPEXEC (propExecRedcost) |
Interface methods | |
SCIP_RETCODE | SCIPincludePropRedcost (SCIP *scip) |
#define PROP_NAME "redcost" |
Definition at line 40 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define PROP_DESC "reduced cost strengthening propagator" |
Definition at line 41 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define PROP_TIMING SCIP_PROPTIMING_DURINGLPLOOP | SCIP_PROPTIMING_AFTERLPLOOP |
Definition at line 42 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define PROP_PRIORITY +1000000 |
propagator priority
Definition at line 43 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define PROP_FREQ 1 |
propagator frequency
Definition at line 44 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define PROP_DELAY FALSE |
should propagation method be delayed, if other propagators found reductions?
Definition at line 45 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define DEFAULT_CONTINUOUS FALSE |
should reduced cost fixing be also applied to continuous variables?
Definition at line 55 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define DEFAULT_USEIMPLICS TRUE |
should implications be used to strength the reduced cost for binary variables?
Definition at line 56 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
#define DEFAULT_FORCE FALSE |
should the propagator be forced even if active pricer are present? Note that the reductions are always valid, but installing an upper bound on priced variables may lead to problems in pricing (existing variables at their upper bound may be priced again since they may have negative reduced costs)
Definition at line 57 of file prop_redcost.c.
Referenced by SCIPincludePropRedcost().
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propagate the given binary variable/column using the root reduced cost stored in the SCIP internal data structures and check if the implications can be useful. Depending on that implications are used or not used during the search to strength the reduced costs.
scip | SCIP data structure |
propdata | propagator data structure |
var | variable to use for propagation |
col | LP column of the variable |
cutoffbound | the current cutoff bound |
nchgbds | pointer to count the number of bound changes |
Definition at line 94 of file prop_redcost.c.
References FALSE, MAX, propagateRedcostBinvar(), SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_CALL, SCIP_INVALID, SCIP_OKAY, SCIP_Real, SCIPchgVarLb(), SCIPchgVarUb(), SCIPcolGetBasisStatus(), SCIPdebugMsg, SCIPgetDepth(), SCIPgetVarImplRedcost(), SCIPgetVarRedcost(), SCIPisDualfeasNegative(), SCIPisDualfeasPositive(), SCIPisDualfeasZero(), SCIPisLPDualReliable(), SCIPvarGetBestRootLPObjval(), SCIPvarGetBestRootRedcost(), SCIPvarGetBestRootSol(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetUbLocal(), and TRUE.
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propagate the given binary variable/column using the reduced cost
scip | SCIP data structure |
propdata | propagator data structure |
var | variable to use for propagation |
col | LP column of the variable |
requiredredcost | required reduset cost to be able to fix a binary variable |
nchgbds | pointer to count the number of bound changes |
cutoff | pointer to store if an cutoff was detected |
Definition at line 217 of file prop_redcost.c.
References FALSE, propagateRedcostVar(), SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_Real, SCIPchgVarLb(), SCIPchgVarUb(), SCIPcolGetBasisStatus(), SCIPdebugMsg, SCIPerrorMessage, SCIPgetColRedcost(), SCIPgetVarImplRedcost(), SCIPgetVarRedcost(), SCIPisDualfeasNegative(), SCIPisDualfeasPositive(), SCIPisDualfeasZero(), SCIPisFeasEQ(), SCIPisLPDualReliable(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetUbLocal(), and TRUE.
Referenced by propagateRootRedcostBinvar().
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propagate the given none binary variable/column using the reduced cost
scip | SCIP data structure |
var | variable to use for propagation |
col | LP column of the variable |
lpobjval | objective value of the current LP |
cutoffbound | the current cutoff bound |
nchgbds | pointer to count the number of bound changes |
Definition at line 351 of file prop_redcost.c.
References SCIP_BASESTAT_BASIC, SCIP_BASESTAT_LOWER, SCIP_BASESTAT_UPPER, SCIP_BASESTAT_ZERO, SCIP_Bool, SCIP_CALL, SCIP_DECL_PROPCOPY(), SCIP_INVALIDDATA, SCIP_OKAY, SCIP_Real, SCIPadjustedVarLb(), SCIPadjustedVarUb(), SCIPchgVarLb(), SCIPchgVarUb(), SCIPcolGetBasisStatus(), SCIPcolGetLb(), SCIPcolGetMaxPrimsol(), SCIPcolGetMinPrimsol(), SCIPcolGetUb(), SCIPdebugMsg, SCIPerrorMessage, SCIPgetColRedcost(), SCIPisDualfeasNegative(), SCIPisDualfeasPositive(), SCIPisDualfeasZero(), SCIPisEQ(), SCIPisFeasEQ(), SCIPisFeasLT(), SCIPisLPDualReliable(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetUbLocal(), and SCIPvarIsIntegral().
Referenced by propagateRedcostBinvar().
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copy method for propagator plugins (called when SCIP copies plugins)
Definition at line 502 of file prop_redcost.c.
Referenced by propagateRedcostVar().
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destructor of propagator to free user data (called when SCIP is exiting) ! [SnippetPropFreeRedcost]
Definition at line 517 of file prop_redcost.c.
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! [SnippetPropFreeRedcost] solving process initialization method of propagator (called when branch and bound process is about to begin)
Definition at line 535 of file prop_redcost.c.
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reduced cost propagation method for an LP solution
Definition at line 550 of file prop_redcost.c.