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BLACS - Basic Linear Algebra Communication Subprograms

Installed Platforms

Version 1.1 of the BLACS, including the 3rd patch set, is available on the following platforms:

  • Itanium Linux Myrinet Cluster (mpi.myrinet), for the 8.1 Intel Compilers
  • 4-way Itanium nodes (mpi.shmem), for the 8.1 Intel Compilers
  • SGI Altix (mpi.altix), for the 8.1 Intel Compilers
  • Pentium III Linux Myrinet Cluster (mpi.myrinet), for the 8.1 Intel Compilers
  • IA32 Linux nodes (mpi.shmem), for the 8.1 Intel Compilers

Note that the mpi.xxx in brackets above refers to the MPI environment module which needs to be loaded prior to initializing BLACS.

Usage

First, check that the appropriate MPI environment is loaded. If the default supplied at login is not suitable for your purpose, you might need to issue a module switch .... Then, type

module load blacs

Linking Fortran Programs

Using the standard MPI wrapper mpif90, first compile your program, then link all objects with

mpif90 -o myprog.exe myprog.o foo.o ...   $BLACS_LIB

Linking C Programs

Using the standard MPI wrapper mpicc, first compile your program, then link all objects with

mpicc -o myprog.exe myprog.o foo.o ...   $BLACS_LIB_C

Presumably, this should also work for C++ programs using mpiCC.

Running executables

The compiled executables should be run in the usual manner, via mpirun. Note that you will need to set up the same MPI environment as used for the compilation process, otherwise starting your executable will fail.

Furthermore, if your program run fails at some point, and your program (if compiled with the -traceback option of the Intel compiler) points to a BLACS routine as the source of failure, please try adjusting the stack limit: For sh-derived shells, issue

ulimit -s 500000

and for csh-derived shells, issue

limit stacksize 500000

If this does not help, please contact LRZ HPC support, sending a short (!) example code, together with a description of what needs to be done to reproduce the problem.

Documentation

All documentation is provided in PostScript unless explicitly marked otherwise.

Some less relevant documents: