I am interested in leveraging more number of physical cores when solving a MIP problem with mathopt.
Parallelization was easy with CP-SAT by setting the number of search workers
solver.parameters.num_workers = 8 # use 8 cores
I struggling to find the right parameter to enable the solver to use more than 1 core to solve with mathopt. I am using HiGHS solver with mathopt (like below snippet)
params = mathopt.SolveParameters(enable_output=True)
result = mathopt.solve(model, mathopt.SolverType.HIGHS, params=params)
— EDIT —
params = mathopt.SolveParameters(enable_output=True, threads=8)
I get below error:
proto_result = solver.solve(
RuntimeError: INVALID_ARGUMENT: threads not supported for HiGHS solver, this must be set using globals, see HiGHS documentation
tried below:
params = mathopt.SolveParameters(enable_output=True, highs={"threads": 8})
result = mathopt.solve(model, mathopt.SolverType.HIGHS, params=params)
result = math_opt_parameters_pb2.SolveParametersProto(
ValueError: Protocol message HighsOptionsProto has no "threads" field.
Can anybody please help ?
You can export to MPS as seen here:
https://github.com/google/or-tools/blob/stable/ortools/math_opt/io/python/mps_converter_test.py
For some further context, see this recent conversation on the or-tools google group:
https://groups.google.com/g/or-tools-discuss/c/x_gvQQzpisk/m/eOB8v8Q6AQAJ
AFAIK, HiGHS is only multithreaded for LP, not for MIP, so this may not do what you want (better to check with HiGHS team).
We have memory issues with highs in parallel. This is currently disabled.
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