rth.nthreads: Determining the Number of Threads a Routine Uses

In matloff/Rth: Rth: Parallel R through Thrust

Description

Note, this only applies for OpenMP and Intel Thread Building Blocks backends.

Usage

rth.nthreads()

Details

rth.nthreads() will determine the maximum number of threads to use by checking against the environment variable RTH_NUM_THREADS (and in the case of OpenMP, OMP_NUM_THREADS), and failing that, the default for the given backend. For OpenMP this means that the number of cores (physical+logical) will be returned. For Intel Thread Building Blocks, the default is the value -1.

For any function taking nthreads= as an argument, the priority is (highest to lowest):

nthreads argument in the R-level Rth function

RTH_NUM_THREADS environment variable

OMP_NUM_THREADS environment variable (for OpenMP backends)

Number of cores

matloff/Rth documentation built on May 21, 2019, 12:55 p.m.