[Wien] pondering wien2kMPI performance

[Kevin Jorissen]

Dear wien2k community,

I have a few basic questions regarding the MPI/SCALAPACK version of wien2k :

* does anyone have a formula for calculating the memory requirements
of the code (lapw0/1/2) given, say, nmat and nume and the number of
cores used?  It's easy enough for the serial code, but I'm sometimes
baffled by the memory taken by each of the MPI threads when
distributing the job over N cores.  It's sometimes very different from
[serial size in GB] / N_cores.  It makes the queue manager unhappy,
and occasionally I unintentionally overload a node this way.


* I was asked the following question about the MPI wien2k code :
>> So would it be correct to state that your apps are more bandwidth sensitive than latency sensitive?
and I don't know what to answer.  Thinking about LARGE calculations
(hundreds of atoms) I want to say that both will be important ...
Does anyone have a more sophisticated insight here?



cheers,


Kevin Jorissen
University of Washington