Intel MPI

Using Intel MPI on PDC systems.

Available versions

To see which versions of intel mpi are available use the command

module avail intelmpi

Compiling your program using Intel MPI

Intel MPI has two mpicc/mpif90 type wrapper scripts for automatically linking the required MPI libraries and header files.

Using Intel compiler

To use the intel compiler with Intel MPI you must have one of the i-compiler modules loaded, then you can use

mpiifort
mpiicc

to compile and link your MPI programs.

Using gcc

Intel MPI also has wrappers that automatically use gcc

mpigcc
mpif90

If the compiler is invoked using these commands then the version of gcc or gfortran in your $PATH is automatically used to compile

Other wrappers

As well as the compiler specific wrappers you can also use

mpicc -cc=<compiler>
mpifc -f90=<compiler>

Note the PGI compiler is not supported

Running Intel MPI programs using EASY

A. Preparation - once in your home catalog

Your home directory is available on all PDC clusters (Ekman, Ferlin, Povel, Zorn) from an OpenAFS volume. You can create there a configuration file that will be used for authentication within the MPI library. This is an optinal step for Intel MPI. However, because it can be used for MPICH and MVAPICH too, it is recommended to create this file. That makes it more convenient to change between different MPI libraries later.

echo "secretword=<arbitrary-word>" >~/.mpd.conf
chmod 600 ~/.mpd.conf

N.B. Do not use a word that you use somewhere else as password.

B. Repeatedly in interactive sessions and job scripts

To run appliations with Intel MPI you need to start the mpd daemons on the compute nodes before the application can run. These daemons should be stopped again if you stop using MPI programs. The next sections shows an example of a jobscript that can be used with Intel MPI on clusters with the batch system EASY.

#!/bin/bash

# Load the appropriate module of the batch system, t.ex.
module load easy

#Start the mpd daemons: one on every compute node
NR_NODES=$(cat ${SP_HOSTFILE} | wc -l)
mpdboot -n ${NR_NODES} -f ${SP_HOSTFILE}

# Now start the MPI application
mpiexec -n <desired-number-of-mpi-processes> ./my_mpi_prog_1
# Maybe use another MPI program
mpiexec -n <desired-number-of-mpi-processes> ./my_mpi_prog_2

# Done with MPI. Shutdown the mpd daemons.
mpdallexit

The same commands can also be used in interactive jobs. But, before issuing the commands listed above, please do the following preparation.

Determine the nodes that belong to your job. You will get an e-mail that lists the assigned compute nodes or you can use the command spusage for that.
Login to the first node in the list.
Make the environment definitions of the batch job available to your terminal session
$ module load easy
spattach -j <the-number-of-your-job>

Your terminal session uses after this preparation the same environment like a batch job would do. You can now execute your job script manually or issue the commands one by one.

Documentation

For more information see the online documentation on the Intel website.

The documentation is also available in the doc sub-directory of the install directory, e.g. for version 4.0.1.007 of the intel compiler

/pdc/vol/i-compilers/2011.0.013/impi/4.0.1.007/doc

Personal tools

Sections