MKL - Intel Math Kernel Library

To load the default MKL, run the following command: module load mkl. To load a particular version, use  module load mkl/version. For example, use module load mkl/11.2.3 to load MKL version 11.2.3. You can use module spider mkl to view available modules.

This step is required for both building and running MKL applications.

The MKL module will automatically configure your environment to locate the appropriate include files. When linking, however, you have a variety of options to choose from depending on your needs. These options come in the form of environment variables defined by the module. Which variable you include when linking will determine what particular configuration of MKL you get.

Notes:

• 64-bit integers are not supported by the FFTW2 wrappers. (See below.)
• The Intel compilers are specially configured for Intel MKL. If you are using this toolchain, you can use the "-mkl” option when linking in place of $MKL_LIBS.
• The default, multithreaded MKL libraries will automatically run in a single thread if they are called from an OpenMP parallel region. If you want to force single-threaded behavior throughout your program, choose one of the “_SEQ” variables from the list above.

Fortran 95 BLAS/LAPACK Wrappers

To compile Fortran 95 programs with modules, add the $MKL_F95FLAGS variable to your compilation step. If you need 64-bit integers, use the $MKL_F95_FLAGS_INT64 instead. When linking, you will also need to use $MKL_F95LIBS (or $MKL_F95LIBS_INT64 if using 64-bit integers). These variables will allow your programs to use the BLAS and LAPACK wrappers for MKL.

FFTW Wrappers

A number of “wrappers” are provided in the form of environment variables that allow you to use FFTW APIs with MKL. Variables ending in FLAGS should be included with your compilation step, while variables ending in LIBS should be included in your linking step.

Notes:

• FFTW3 is the default wrapper and should be picked up by your linker automatically. If you would prefer to use FFTW2, use the appropriate linking variable.
• The FFTW2 wrappers do not support 64-bit (“ILP64”) integers.

Examples

The following examples use the Intel compilers, though they should work using the GNU and Portland Group compilers as well.

Compiling a Fortran77 program with MKL:

ifort -c my_prog.f
ifort -o my_prog my_prog.o $MKL_LIBS

Compiling a C program with MKL:

icc -c my_prog.c
icc -o my_prog my_prog.o $MKL_LIBS

Compiling a module-based Fortran90/95 program with MKL:

ifort -c my_prog.f95 $MKL_F95FLAGS
ifort -o my_prog my_prog.o $MKL_F95LIBS $MKL_LIBS

Compiling a C program with the double-precision FFTW2 wrapper:

icc -c $MKL_FFTW_CFLAGS -DMKL_DOUBLE my_prog.c
icc -o my_prog my_prog.o $MKL_FFTW2_D_CLIBS $MKL_LIBS

Compiling a Fortran77 program with the FFTW2 wrapper:

ifort -c $MKL_FFTW_FFLAGS my_prog.f
ifort -o my_prog my_prog.o $MKL_FFTW2_S_FLIBS $MKL_LIBS

Compiling a C program with the FFTW3 wrapper:

icc -c $MKL_FFTW_CFLAGS my_prog.c
icc -o my_prog my_prog.o $MKL_FFTW3_CLIBS $MKL_LIBS

Compiling a Fortran program with the FFTW3 wrapper:

ifort -c $MKL_FFTW_FFLAGS my_prog.f 
ifort -o my_prog my_prog.o $MKL_FFTW3_CLIBS $MKL_LIBS

If you are already familiar with building MKL applications with your chosen build tool (GCC, Intel, or PGI) and you do not wish to use the convenience variables discussed above, you may wish to use the $MKLROOT variable instead. This variable points to the installation directory for Intel MKL. All include files can be found in $MKLROOT/include, for example, and the libraries are in $MKLROOT/lib/intel64.

When running an MKL program, you need to be sure to take the following steps.

1. Load the mkl module:

   module load mkl
   

2. If running with parallel MKL, set OMP_NUM_THREADS to match the number of cores per node in your process. In the bash shell, you can accomplish this with:

   PPNPERNODE=$(expr $(cat $PBS_NODEFILE | wc -l) / $(uniq $PBS_NODEFILE | wc -l))
   export OMP_NUM_THREADS=$PPNPERNODE
   

To load the default MKL, run the following command: module load mkl. To load a particular version, use  module load mkl/version. For example, use  module load mkl/11.2.3 to load MKL version 11.2.3. You can use module spider mkl to view available modules.

This step is required for both building and running MKL applications.

To load the default MKL, run the following command: module load mkl. To load a particular version, use  module load mkl/version. For example, use module load mkl/11.3.3 to load MKL version 11.3.3. You can use module spider mkl to view available modules.

This step is required for both building and running MKL applications.