timeLimit Parameter Ignored in pulp.FSCIP_CMD Solver

[kami9811]

Details for the issue

What did you do?

I attempted to use the timeLimit parameter with the pulp.FSCIP_CMD solver to restrict the optimization time for solving a linear programming problem. The parameter was set as an argument while initializing the FSCIP_CMD solver instance.

What did you expect to see?

I expected the solver to halt the optimization process when the specified time limit was reached, thereby respecting the time constraint set by timeLimit.

What did you see instead?

Despite specifying the timeLimit parameter, the solver seems to ignore this constraint and continues the optimization process beyond the set time limit. The optimization completes, but it does so in a time frame that exceeds the specified limit, indicating that the timeLimit parameter is not being effectively enforced or recognized by the solver.

Useful extra information

In pulp.SCIP_CMD, the parameter is fine as expected.

What operating system are you using?

• Windows: ( version: ___ )
• Linux: ( distro: ___ )
• Mac OS: ( version: ___ )
• Other: ___

I'm using python version:

• 2.7
• 3.4
• 3.5
• 3.6
• Other: 3.10

I installed PuLP via:

• pypi (python -m pip install pulp)
• github (python -m pip install -U git+https://github.com/coin-or/pulp)
• Other: ___ (conda?)

Did you also

• Tried out the latest github version: https://github.com/coin-or/pulp
• Searched for an existing similar issue: https://github.com/coin-or/pulp/issues?utf8=%E2%9C%93&q=is%3Aissue%20

[pchtsp]

Hello! thanks for the report. can you provide the logs of the solver? or a reproducible example?

[berkomeratay]

I also have this this issue with FSCIP_CMD api, only difference with the issue holder @kami9811 is that I have installed PuLP via pip. I guess this is a common bug for both versions.

I just went around the problem by giving options = ["TimeLimit = 60"] for a minute long limit.

But there might be something troubling here since:

As far as I understand from scip_api.py this api tries to give fscip limits/time parameter which is a scip parameter.

Since FSCIP uses UG I looked at their documentation as well and UG uses TimeLimit, I guess that's why it worked. I am not an expert on this, I might have been using the terms wrong but if you need a practical solution you can use the options for time limit.