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probing propagator
- Author
- Tobias Achterberg
Definition in file prop_probing.h.
Go to the source code of this file.
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| SCIP_RETCODE | SCIPincludePropProbing (SCIP *scip) |
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| SCIP_RETCODE | SCIPapplyProbingVar (SCIP *scip, SCIP_VAR **vars, int nvars, int probingpos, SCIP_BOUNDTYPE boundtype, SCIP_Real bound, int maxproprounds, SCIP_Real *impllbs, SCIP_Real *implubs, SCIP_Real *proplbs, SCIP_Real *propubs, SCIP_Bool *cutoff) |
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| SCIP_RETCODE | SCIPanalyzeDeductionsProbing (SCIP *scip, SCIP_VAR *probingvar, SCIP_Real leftub, SCIP_Real rightlb, int nvars, SCIP_VAR **vars, SCIP_Real *leftimpllbs, SCIP_Real *leftimplubs, SCIP_Real *leftproplbs, SCIP_Real *leftpropubs, SCIP_Real *rightimpllbs, SCIP_Real *rightimplubs, SCIP_Real *rightproplbs, SCIP_Real *rightpropubs, int *nfixedvars, int *naggrvars, int *nimplications, int *nchgbds, SCIP_Bool *cutoff) |
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creates the probing propagator and includes it in SCIP
- Parameters
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| SCIP_RETCODE SCIPapplyProbingVar |
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SCIP * |
scip, |
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SCIP_VAR ** |
vars, |
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int |
nvars, |
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int |
probingpos, |
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SCIP_BOUNDTYPE |
boundtype, |
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SCIP_Real |
bound, |
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int |
maxproprounds, |
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SCIP_Real * |
impllbs, |
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SCIP_Real * |
implubs, |
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SCIP_Real * |
proplbs, |
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SCIP_Real * |
propubs, |
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SCIP_Bool * |
cutoff |
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applies and evaluates probing of a single variable in the given direction and bound
- Parameters
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| scip | SCIP data structure |
| vars | problem variables |
| nvars | number of problem variables |
| probingpos | variable number to apply probing on |
| boundtype | which bound should be changed |
| bound | whioch bound should be set |
| maxproprounds | maximal number of propagation rounds (-1: no limit, 0: parameter settings) |
| impllbs | array to store lower bounds after applying implications and cliques |
| implubs | array to store upper bounds after applying implications and cliques |
| proplbs | array to store lower bounds after full propagation |
| propubs | array to store upper bounds after full propagation |
| cutoff | pointer to store whether the probing direction is infeasible |
| SCIP_RETCODE SCIPanalyzeDeductionsProbing |
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SCIP * |
scip, |
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SCIP_VAR * |
probingvar, |
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SCIP_Real |
leftub, |
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SCIP_Real |
rightlb, |
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int |
nvars, |
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SCIP_VAR ** |
vars, |
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SCIP_Real * |
leftimpllbs, |
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SCIP_Real * |
leftimplubs, |
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SCIP_Real * |
leftproplbs, |
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SCIP_Real * |
leftpropubs, |
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SCIP_Real * |
rightimpllbs, |
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SCIP_Real * |
rightimplubs, |
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SCIP_Real * |
rightproplbs, |
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SCIP_Real * |
rightpropubs, |
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int * |
nfixedvars, |
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int * |
naggrvars, |
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int * |
nimplications, |
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int * |
nchgbds, |
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SCIP_Bool * |
cutoff |
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analyses boundchanges resulting from probing on a variable and performs deduced fixations, aggregations, and domain tightenings
Given a variable probingvar with domain [l,u] and bound tightening results from reducing the domain once to [l,leftub] and once to [rightlb,u], the method computes and applies resulting variable fixations, aggregations, implications, and bound changes. Variable probingvar does not need to be binary. The whole domain of probingvar need to be covered by the left and right branches, i.e., we assume leftub >= rightlb for continuous variables or floor(leftub) >= ceil(rightlb)-1 for discrete variables. Bounds after applying implications and cliques do not need to be provided, but if they are omitted and probingvar is a binary variable, then already existing implications may be added.
- Parameters
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| scip | SCIP data structure |
| probingvar | the probing variable |
| leftub | upper bound of probing variable in left branch |
| rightlb | lower bound of probing variable in right branch |
| nvars | number of variables which bound changes should be analyzed |
| vars | variables which bound changes should be analyzed |
| leftimpllbs | lower bounds after applying implications and cliques in left branch, or NULL |
| leftimplubs | upper bounds after applying implications and cliques in left branch, or NULL |
| leftproplbs | lower bounds after applying domain propagation in left branch |
| leftpropubs | upper bounds after applying domain propagation in left branch |
| rightimpllbs | lower bounds after applying implications and cliques in right branch, or NULL |
| rightimplubs | upper bounds after applying implications and cliques in right branch, or NULL |
| rightproplbs | lower bounds after applying domain propagation in right branch |
| rightpropubs | upper bounds after applying domain propagation in right branch |
| nfixedvars | pointer to counter which is increased by the number of deduced variable fixations |
| naggrvars | pointer to counter which is increased by the number of deduced variable aggregations |
| nimplications | pointer to counter which is increased by the number of deduced implications |
| nchgbds | pointer to counter which is increased by the number of deduced bound tightenings |
| cutoff | buffer to store whether a cutoff is detected |
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