registerDoMC function is used to register the multicore
parallel backend with the
The number of cores to use for parallel execution. If not specified, the number of cores is set to the value of
options("cores"), if specified, or to approximately half the number of cores detected by the
Package options. Currently, only the
nocompileoption is supported. If
nocompileis set to
TRUE, compiler support is disabled.
multicore functionality, originally written by Simon Urbanek and
subsumed in the
parallel package in R 2.14.0, provides functions
for parallel execution of R code on machines with multiple cores or
fork call to spawn copies of the current process. The
multicore functionality, and therefore
not be used
in a GUI environment, because multiple processes then share the same GUI.