## Detailed Description

constraint handler for orbisack constraints

The constraint works on two vectors of variables, which are interpreted as columns of a matrix such that the first column is lexicographically not smaller than the second.

Definition in file cons_orbisack.h.

`#include "scip/def.h"`

`#include "scip/type_cons.h"`

`#include "scip/type_retcode.h"`

`#include "scip/type_scip.h"`

`#include "scip/type_sol.h"`

`#include "scip/type_var.h"`

Go to the source code of this file.

## Functions | |

SCIP_RETCODE | SCIPincludeConshdlrOrbisack (SCIP *scip) |

Orbisack Constraints | |

This constraint handler can be used to handle symmetries in certain 0/1-programs. The principle structure is that some variables can be ordered in matrix form with two columns, such that permuting both columns does not change the validity and objective function value of a solution. That is, there exists a permutation symmetry of the program that permutes the variables of the first and second column row-wise. In more mathematical terms the structure has to be as follows: There are 0/1-variables \(x_{ij}\), \(i \in \{1, \dots, n\}\), \(j \in \{1, 2\}\). Permuting columns of \(x\) does not change the validity and objective function value of any feasible solution. | |

SCIP_RETCODE | SCIPcheckSolutionOrbisack (SCIP *scip, SCIP_SOL *sol, SCIP_VAR **vars1, SCIP_VAR **vars2, int nrows, SCIP_Bool printreason, SCIP_Bool *feasible) |

SCIP_RETCODE | SCIPcreateConsOrbisack (SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR *const *vars1, SCIP_VAR *const *vars2, int nrows, SCIP_Bool ispporbisack, SCIP_Bool isparttype, SCIP_Bool ismodelcons, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode) |

SCIP_RETCODE | SCIPcreateConsBasicOrbisack (SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR **vars1, SCIP_VAR **vars2, int nrows, SCIP_Bool ispporbisack, SCIP_Bool isparttype, SCIP_Bool ismodelcons) |