warm start LP solver in Gurobi
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Hi,
I have two questions related to solving LPs.
- When I warm start the LP solver, it seems the LP solver automatically switches to the single thread mode, while I allocate 4 threads to it.
- When I use 4 threads, it seems the solving time of my LP can be reduced much more than four times as compared to using a single thread.
Can you please explain to me what is going on under the hood?
Thanks,
Yunzhuang
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Hi Yunzhuang,
When supplying a warm start solution, Gurobi will use the simplex method to solve the LP and only the barrier method is able to utilize more than one thread. The barrier method cannot be warm started, though.
Quite possibly, the observed performance difference is not directly due to the 4 threads but rather due to a different algorithm - in this case, the barrier - being used.
Please refer to these sections in our documentation for further information on how to interpret the LP logs:
I hope that answers your questions.
Cheers,
Matthias0 -
Thanks, Matthias. The answer makes sense to me.
Regards,
Yunzhuang
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