/** adds all constraints in conjunction constraints to the problem; disables unmodifiable conjunction constraints */
static
SCIP_RETCODE addAllConss(
SCIP* scip, /**< SCIP data structure */
SCIP_CONS** conss, /**< active conjunction constraints */
int nconss, /**< number of active conjunction constraints */
SCIP_RESULT* result /**< pointer to store the result */
)
{
SCIP_CONSDATA* consdata;
int c;
int i;
assert(result != NULL);
for( c = 0; c < nconss; ++c )
{
consdata = SCIPconsGetData(conss[c]);
assert(consdata != NULL);
/* add all inactive constraints to local subproblem */
for( i = 0; i < consdata->nconss; ++i )
{
/* update check flag for sub constraints when upgrade takes place */
if( SCIPconsIsChecked(conss[c]) )
{
/* make sure, the constraint is checked for feasibility */
SCIP_CALL( SCIPsetConsChecked(scip, consdata->conss[i], TRUE) );
}
if( !SCIPconsIsActive(consdata->conss[i]) )
{
SCIPdebugMessage("adding constraint <%s> from add conjunction <%s>\n",
SCIPconsGetName(consdata->conss[i]), SCIPconsGetName(conss[c]));
SCIP_CALL( SCIPaddConsLocal(scip, consdata->conss[i], NULL) );
*result = SCIP_CONSADDED;
}
}
/* disable conjunction constraint, if it is unmodifiable */
if( !SCIPconsIsModifiable(conss[c]) )
{
SCIP_CALL( SCIPdelConsLocal(scip, conss[c]) );
}
}
return SCIP_OKAY;
}
/** propagation method for disjunction constraint */
static
SCIP_RETCODE propagateCons(
SCIP* scip, /**< SCIP data structure */
SCIP_CONS* cons, /**< knapsack constraint */
int* ndelconss /**< pointer to count number of deleted constraints */
)
{
SCIP_CONSDATA* consdata;
SCIP_CONS** conss;
int nconss;
int c;
assert(scip != NULL);
assert(cons != NULL);
assert(ndelconss != NULL);
consdata = SCIPconsGetData(cons);
assert(consdata != NULL);
conss = consdata->conss;
assert(conss != NULL);
nconss = consdata->nconss;
assert(nconss > 1);
for( c = 0; c < nconss; ++c )
{
if( SCIPconsIsActive(conss[c]) )
{
(*ndelconss)++;
SCIP_CALL( SCIPdelConsLocal(scip, cons) );
break;
}
}
return SCIP_OKAY;
}
/** initializes the pricing problem for the given capacity */
static
SCIP_RETCODE initPricing(
SCIP* scip, /**< SCIP data structure */
SCIP_PRICERDATA* pricerdata, /**< pricer data */
SCIP* subscip, /**< pricing SCIP data structure */
SCIP_VAR** vars /**< variable array for the items */
)
{
SCIP_CONS** conss;
SCIP_Longint* vals;
SCIP_CONS* cons;
SCIP_VAR* var;
SCIP_Longint* weights;
SCIP_Longint capacity;
SCIP_Real dual;
int nitems;
int nvars;
int c;
assert( SCIPgetStage(subscip) == SCIP_STAGE_PROBLEM );
assert(pricerdata != NULL);
nitems = pricerdata->nitems;
conss = pricerdata->conss;
weights = pricerdata->weights;
capacity = pricerdata->capacity;
nvars = 0;
SCIP_CALL( SCIPallocBufferArray(subscip, &vals, nitems) );
/* create for each order, which is not assigned yet, a variable with objective coefficient */
for( c = 0; c < nitems; ++c )
{
cons = conss[c];
/* check if each constraint is setppc constraint */
assert( !strncmp( SCIPconshdlrGetName( SCIPconsGetHdlr(cons) ), "setppc", 6) );
/* constraints which are (locally) disabled/redundant are not of
* interest since the corresponding job is assigned to a packing
*/
if( !SCIPconsIsEnabled(cons) )
continue;
if( SCIPgetNFixedonesSetppc(scip, cons) == 1 )
{
/* disable constraint locally */
SCIP_CALL( SCIPdelConsLocal(scip, cons) );
continue;
}
/* dual value in original SCIP */
dual = SCIPgetDualsolSetppc(scip, cons);
SCIP_CALL( SCIPcreateVarBasic(subscip, &var, SCIPconsGetName(cons), 0.0, 1.0, dual, SCIP_VARTYPE_BINARY) );
SCIP_CALL( SCIPaddVar(subscip, var) );
vals[nvars] = weights[c];
vars[nvars] = var;
nvars++;
/* release variable */
SCIP_CALL( SCIPreleaseVar(subscip, &var) );
}
/* create capacity constraint */
SCIP_CALL( SCIPcreateConsBasicKnapsack(subscip, &cons, "capacity", nvars, vars, vals,
capacity) );
SCIP_CALL( SCIPaddCons(subscip, cons) );
SCIP_CALL( SCIPreleaseCons(subscip, &cons) );
/* add constraint of the branching decisions */
SCIP_CALL( addBranchingDecisionConss(scip, subscip, vars, pricerdata->conshdlr) );
/* avoid to generate columns which are fixed to zero */
SCIP_CALL( addFixedVarsConss(scip, subscip, vars, conss, nitems) );
SCIPfreeBufferArray(subscip, &vals);
return SCIP_OKAY;
}
