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This routine returns the linear constraints and variables belonging
to a conflict previously computed by the routine
CPXrefineconflict. The conflict is a subset
of constraints and variables from the original, infeasible model
that is still infeasible. It is generally minimal, in the sense that
removal of any of the constraints or variable bounds in the conflict will
make the conflict set become feasible. However, the
computed conflict will not be minimal if the previous call to
CPXrefineconflict was not allowed to run to completion.
Conflict Status
The status of the currently available conflict is returned in
confstat_p. If CPXrefineconflict was
called previously, the status will be one of the following values:
CPX_STAT_CONFLICT_MINIMAL,CPX_STAT_CONFLICT_FEASIBLE, or CPX_STAT_CONFLICT_ABORT_reason.When the status of a conflict is CPX_STAT_CONFLICT_FEASIBLE,
the routine CPXrefineconflict determined that the model
was feasible, and thus no conflict is available. Otherwise, a conflict
is returned. The returned conflict is minimal if the status is
CPX_STAT_CONFLICT_MINIMAL.
The conflict status can also be queried with the
routine CPXgetstat.
Row and Column Status
In the array rowbdstat, integer values are returned specifying
the status of the corresponding row in the conflict. For row
rowind[i], rowbdstat[i] can assume the value
CPX_CONFLICT_MEMBER for constraints
that participate in a minimal conflict. When the computed conflict
is not minimal, rowbdstat[i] can assume the value
CPX_CONFLICT_POSSIBLE_MEMBER, to indicate that row i has not
been proven to be part of the conflict. If a row has been proven not
to belong to the conflict, its index will not be listed in
rowind.
Similarly, the array colbdstat
contains integers indicating the status of
the variable bounds in the conflict. The value specified in
colbdstat[i] is the conflict status
for variable colind[i]. If colind[i]
has been proven to be part of the
conflict, colbdstat[i] will take one of the following values:
CPX_CONFLICT_MEMBER, CPX_CONFLICT_LB, or CPX_CONFLICT_UB. When variable colind[i] has neither been proven to belong
nor been proven not to belong
to the conflict, the status colbdstat[i] will be one of
the following values:
CPX_CONFLICT_POSSIBLE_MEMBER, CPX_CONFLICT_POSSIBLE_LB, or CPX_CONFLICT_POSSIBLE_UB. In both cases, the _LB status indicates that only the lower bound is part of the conflict. Similarly, the _UB status indicates that the upper bound is part of the conflict. Finally, if both bounds are required in the conflict, a _MEMBER status is assigned to that variable.
The status values marked POSSIBLE
specify that the corresponding constraints
and variables in the conflict are possibly not required to produce
a minimal conflict, but the conflict
refinement algorithm was not able to remove them
before it terminated (for example, because it reached a time limit
set by the user).
See Also:
CPXrefineconflict, CPXclpwrite
| env | A pointer to the CPLEX environment as returned by the routine |
| lp | A pointer to a CPLEX problem object as returned by |
| confstat_p | A pointer to an integer used to return the status of the conflict. |
| rowind | An array to receive the list of the indices of the constraints that participate in the conflict. The length of the array must not be less than the number of rows in the conflict. If that number is not known, use the total number of rows in the problem object instead. |
| rowbdstat | An array to receive the conflict status of the rows. Entry |
| confnumrows_p | A pointer to an integer where the number of rows in the conflict is returned. |
| colind | An array to receive the list of the indices of the variables that participate in the conflict. The length of the array must not be less than the number of columns in the conflict. If that number is not known, use the number of columns in the problem object instead. |
| colbdstat | An array to receive the conflict status of the columns. Entry |
| confnumcols_p | A pointer to an integer where the number of columns in the conflict is returned. |