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Specify the number of threads that SimInf should use

Source: R/openmp.R
set_num_threads.Rd

Set the number of threads to be used in SimInf code that is parallelized with OpenMP (if available). The number of threads is initialized when SimInf is first loaded in the R session using optional envioronment variables (see ‘Details’). It is also possible to specify the number of threads by calling set_num_threads. If the environment variables that affect the number of threads change, then set_num_threads must be called again for it to take effect.

Usage

set_num_threads(threads = NULL)

Arguments

threads

integer with maximum number of threads to use in functions that are parallelized with OpenMP (if available). Default is NULL, i.e. to use all available processors and then check for limits in the environment varibles (see ‘Details’).

Value

The previous value is returned (invisible).

Details

The omp_get_num_procs() function is used to determine the number of processors that are available to the device at the time the routine is called. The number of threads is then limited by omp_get_thread_limit() and the current values of the environmental variables (if set)

  • Sys.getenv("OMP_THREAD_LIMIT")

  • Sys.getenv("OMP_NUM_THREADS")

  • Sys.getenv("SIMINF_NUM_THREADS")

Additionally, the maximum number of threads can be controlled by the threads argument, given that its value is not above any of the limits described above.