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parallel-processingmathematical-optimizationscip

Use of threads in SCIP

In the list of SCIP's parameters I see three types of references to the use of threads:

  • lp/threads (threads used for solving the LP, which don't matter when using SoPlex, according to this question).

  • parallel/{min, max}threads (number of threads during parallel solve).

  • concurrent/* (parameters related to the use of threads in concurrent mode).

My question(s) is(are): How are threads used in SCIP when using a default installation? Are the parallel/{min, max}threads parameters related only to the concurrent solver? If I don't turn on the concurrent solver, would SCIP use the available threads for solving the branch-and-bound subproblems in parallel?

Thanks in advance!

Solution

  • All parameters in the "parallel/" and "concurrent/" sections of the SCIP parameter space only affect the concurrent mode.

    SCIP is by default single-threaded, but can be parallelized using the UG-framework or by enabling the concurrent mode.