MVAPICH2

MPI is a standard library for performing parallel processing using a distributed-memory model. 

Availability & Restrictions

MPI is available without restriction to all OSC users.

The following versions of MVAPICH2 are available on OSC systems:

Version Oakley Ruby Owens
1.7 X    
1.8 X    
1.9 X X  
2.1 X* X*  
2.2     X*
NOTE: *Default version.

Usage

Set-up

To set up your environment for using the MPI libraries, you must load the appropriate module:

module load mvapich2

You will get the default version for the compiler you have loaded.

Note:Be sure to swap the intel compiler module for the gnu module if you're using gnu.

Building With MPI

To build a program that uses MPI, you should use the compiler wrappers provided on the system. They accept the same options as the underlying compiler. The commands are shown in the following table.

C mpicc
C++ mpicxx
FORTRAN 77 mpif77
Fortran 90 mpif90

For example, to build the code my_prog.c using the -O2 option, you would use:

mpicc -o my_prog -O2 my_prog.c

In rare cases you may be unable to use the wrappers. In that case you should use the environment variables set by the module.

Variable Use
$MPI_CFLAGS Use during your compilation step for C programs.
$MPI_CXXFLAGS Use during your compilation step for C++ programs.
$MPI_FFLAGS Use during your compilation step for Fortran 77 programs.
$MPI_F90FLAGS Use during your compilation step for Fortran 90 programs.
$MPI_LIBS Use when linking your program to the MPI libraries.

For example, to build the code my_prog.c without using the wrappers you would use:

mpicc -c $MPI_CFLAGS my_prog.c

mpicc -o my_prog my_prog.o $MPI_LIBS

Batch Usage

Programs built with MPI can only be run in the batch environment at OSC. For information on starting MPI programs using the mpiexec command, see Batch Processing at OSC.

Be sure to load the same compiler and mvapich modules at execution time as at build time.

Further Reading

See Also

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