Originally posted by: SystemAdmin

[hernan said:]

Hi everybody!
When CPXmipopt finishes, I want to get the last gap information that appears in the log file, so if CPXmipopt execution finishes caused by Time Limit, I want to know the %gap. Is it possible using CPLEX Callable Library or I must parse the log file??
Thanks!

#DecisionOptimization
#MathematicalProgramming-General

Originally posted by: SystemAdmin

[johncui said:]

Please try:

CPXgetmiprelgap
int CPXgetmiprelgap(CPXCENVptr env, CPXCLPptr lp, double * gap_p)
Definition file: cplex.h
The routine CPXgetmiprelgap accesses the relative objective gap for a MIP optimization.

For a minimization problem, this value is computed by

(bestinteger - bestobjective) / (1e-10 + |bestobjective|)
where bestinteger is the value returned by CPXgetobjval and bestobjective is the value returned by CPXgetbestobjval. For a maximization problem, the value is computed by:

(bestobjective - bestinteger) / (1e-10 + |bestobjective|)

Example

status = CPXgetmiprelgap (env, lp, &gap);

Parameters:
env A pointer to the CPLEX environment as returned by CPXopenCPLEX.

lp A pointer to a CPLEX problem object as returned by CPXcreateprob.

gap_p A pointer to the location where the relative mip gap is returned.


Returns:
The routine returns zero if successful and nonzero if an error occurs.
#DecisionOptimization
#MathematicalProgramming-General