Originally posted by: SystemAdmin

[carali said:]

I'm solving MIP problems using Cplex 9.0 in a C++ program. To reduce time , I set a maximum number of seconds to each Cplex solve().
IloCplex cplex(env);
cplex.extract(model);
cplex.setParam(IloCplex::TiLim,600);
cplex.solve();
What I find strange is that Cplex won't stop when time is 600s firstly. Then, Cplex  count time from 0, when time isn't 600s secondly, Cplex stop. Why?
Who can help me?
Thanks very much.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

[EdKlotz said:]

CPLEX has certain procedures (e.g. presolve, some cut generation) that don't check the time limit until the procedure is finished.    The time limit is checked essentially once per subproblem, so if one of these other procedures takes a long time, you may encounter a significant delay before the time limit is checked.
So, look at the CPLEX node log and try to assess what CPLEX is doing at the time the run passes the
600 second time limit.  If CPLEX appears to be generating cuts, try turning off cut generation, just to
see what's happening.  If you need assistance with interpreting the node log output, either post it
on this forum or provide a URL where the forum members can have a look.
#CPLEXOptimizers
#DecisionOptimization