Howto - OpenMP and/or Intel MKL
This is not a whyto/howto parallelisation. There are many reasons to do this. Instead, just a quick guide is given here to running such calculations on getfix. Both the GNU-based compilers and the Intel compiler are able to handle the OpenMP protocol if it is included in your source code.
gnu compiler, OpenMP, and LAPACK/BLAS
For the gnu compiler (gcc, g++, gfortran)
the basic -fopenmp option will enable any OpenMP commands in your source code.
The system GNU compiled LAPACK and BLAS (-llapack -lblas) are not parallelised.
Intel compiler, OpenMP, and LAPACK/BLAS via Intel MKL
For the Intel compiler (icc, ifort)
the basic -openmp command will enable any OpenMP commands in your source code.
The Intel MKL compiled LAPACK and BLAS require special commands at compile time:
@@
-Wl,--start-group -lmkl_intel_lp64 -lmkl_sequential -lmkl_core -Wl,--end-group
@@ which explicitly links to the single-processor version of the intel MKL.
To link to the multi-core Intel MKL do:
@@
-Wl,--start-group -lmkl_intel_lp64 -lmkl_intel_thread -lmkl_core -Wl,--end-group -openmp -lpthread
@@
These commands change from compiler version to version.
The best way to work out the options for the Intel compiler are to use the [[https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/| https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/]]
Example multicore/OpenMP/Intel MKL script
Slurm openmp example needed.
Note that you are able to separately control the number of threads that OpenMP and the Intel MKL will spawn.