[Wien] Wien on Cray XT4

[Bernd Kallies]

There was a note regarding problems about running Wien2k on a Cray XT4
cluster in october 2007.

The general problem was that the micro kernel on Cray XT4 compute nodes
did not allow to run scripts or launching subprocesses, which introduces
problems when executing k-point parallel runs via the Wien2k script
framework.

I'd like to mention that I provided the Wien2k developers in August 2007
with a Wien2k version that implements the k-point parallelization scheme
fully within MPI, yielding a two-level MPI parallelization scheme. I
originally developed this for running lapw1 and lapw2 on several IBM
32-way SMP nodes, and also tested this on usual Linux clusters. It does
not need the complicated script framework or a .machines file, and does
not need heavy code changes. I regard this solution as more suitable for
computing centres or architectures, where logging in into remote compute
nodes to start processes outside of the control of a batch queuing
system is not allowed or not possible.

If anybody is interested in this, I suggest to contact the Wien2k
developers.

Sincerely, BK

-- 
Dr. Bernd Kallies
Konrad-Zuse-Zentrum für Informationstechnik Berlin
Takustr. 7
14195 Berlin
Tel: +49-30-84185-270
Fax: +49-30-84185-311
e-mail: kallies at zib.de