Query about launching multiple local solvers through a single AMPL instance
M I Shafique
I have a question about simultaneous launch of multiple local solvers through a single AMPL instance.
In my problem I have a scenario where I would like to explore multiple areas of a variable space simultaneously using multiple launches of local solvers. For example, I plan to run multiple instances of IPOPT(with different initial values, on same model) at the same time. Is it possible by a single instance of AMPL? I am worried if the value of problem variables would be inter-mingled by different instances of IPOPT.
Alternatively, will it help if I launch multiple instances of AMPL, each interacting with a single local solver(IPOPT)?
Thank you and regards,
MS
Robert Fourer
It should be possible to set up an AMPL loop to do the kind of processing you describe. The papers listed below describe an approach that uses one AMPL process to spawn multiple solver processes, using a combination of AMPL features and some auxiliary programming. No doubt your situation will be different from these in some ways, but the same ideas should apply.
You could also try launching multiple instances of AMPL, each of which would launch a separate instance of the solver and would leave behind some results (as a text file or AMPL .sol file). The processing of the results would have to take place separately, however.
Regards,
Bob Fourer
Michael C. Ferris and Todd S. Munson, Modeling Languages and Condor: Metacomputing for Optimization. dx.doi.org/10.1007/PL00011382: Mathematical Programming 88 (2000) 487-505.
Elizabeth D. Dolan, Robert Fourer, Jean-Pierre Goux, Todd S. Munson and Jason Sarich, Kestrel: An Interface from Optimization Modeling Systems to the NEOS Server. dx.doi.org/10.1287/ijoc.1080.0264: INFORMS Journal on Computing 20 (2008) 525–538.
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Subject: [AMPL 7353] Query about launching multiple local solvers through a single AMPL instance