Math Kernel Library (MKL)

Description

The Intel Math Kernel Library (Intel MKL) contains highly optimized, extensively threaded math routines for science, engineering, and financial applications. Core math functions include BLAS, LAPACK, ScaLAPACK, Sparse Solvers, Fast Fourier Transforms, Vector Math, and more.

NERSC provides MKL on the Carver system for all compilers.  MKL is available on the Hopper system for Intel compiler only.

How to Access MKL on Carver

module load mkl

How to Use MKL on Carver

Linking Your Code with MKL on Carver

Basic usage, with (default) PGI compiler:

mpif90 my_code.f $MKL

Using ScaLAPACK:

mpif90 my_code.f $MKL -L$MKL_LIBDIR -lmkl_scalapack_lp64 -lmkl_blacs_openmpi_lp64

Basic usage, with (default) Intel or gcc compilers (after appropriate module swap commands):

mpicc -c -I$MKL_INC test.c $MKL

Running Your Code with MKL on Carver

The above procedures create static executables. When running your code you may see an error message such as this:

./a.out: error while loading shared libraries: libmkl_intel_lp64.so: 
cannot open shared object file: No such file or directory

There are several possible solutions:

1. The simplest solution is, in your batch script, include the statement "module load mkl".

2. You can also type "module load mkl" from the shell and then include the statement "#PBS -V" in your batch script.

3. This is a two-step procedure. First, type "module load mkl". Then, when linking your code you can include the "-rpath $MKL_LIBDIR" option. Note that in a Makefile the syntax would be something like:

FC   = mpif90
BTLIBS = -L$(MKL_LIBDIR) -lmkl_core -lmkl_blacs_openmpi_lp64
TESTOBJ = hello.o
all: hello.x
hello.x: $(TESTOBJ)
$(FC) -o $@ $(TESTOBJ) $(BTLIBS) -rpath $(MKL_LIBDIR)
.f.o : ; $(FC) -c $(FCFLAGS) $*.f

How to Use MKL on Hopper (Intel compiler only)

Linking Your Code with MKL on Hopper

Just use the "-mkl" flag with the compiler wrappers under the Intel programming environment. The default is to use the threaded libraries ("-mkl" is equivalent to "-mkl=parallel") .  If sequential libraries are needed, use the "-mkl=sequential" flag instead.

module swap PrgEnv-pgi PrgEnv-intel
ftn -mkl my_code.f 
cc -mkl test.c 

If you experience any trouble using the MKL libraries on Carver or Hopper please send e-mail to consult@nersc.gov.

Documentation

The release notes, user's guide, and reference manual are available in PDF and HTML format on the Intel web site.

Intel also has an "MKL Advisor" that can help with choosing linking options.  To see which libraries are recommended for a particular use case view the Intel interactive form.

Availability