Back to SYMPHONY Home Page

user_is_feasible

int user_is_feasible(void *user, double lpetol, int varnum, int
                     *indices, double *values, int *feasible)

Description:

User tests the feasibility of the solution to the current LP relaxation.

There is no post-processing. Possible defaults are testing integrality (TEST_INTEGRALITY) and testing whether the solution is binary (TEST_ZERO_ONE).

Arguments:

void *user	INOUT	Pointer to the user-defined LP data structure.
double lpetol	IN	The $\epsilon$ tolerance of the LP solver.
int varnum	IN	The length of the indices and values arrays.
int *indices	IN	User indices of variables at nonzero level in the current solution.
double *values	IN	Values of the variables listed in indices.
int *feasible	OUT	Feasibility status of the solution ( NOT_FEASIBLE, or FEASIBLE).

Return values:

ERROR	Error. Solution is considered to be not feasible.
USER_NO_PP	User checked IP feasibility.
DEFAULT	Regulated by the parameter is_feasible_default, but set to TEST_INTEGRALITY unless over-ridden by the user.
TEST_INTEGRALITY	Test integrality of the given solution.
TEST_ZERO_ONE	Tests whether the solution is binary.

Wrapper invoked from:

select_branching_object() after pre-solving the LP relaxation of a child corresponding to a candidate and from fathom_branch() after solving an LP relaxation.