[Wien] Doubt in mpi running of Wien2K

[Peter Blaha]

Please read the UG (section about parallelization).
There is no k-parallelzation using mpi.

PS: Did you set a local SCRATCH directory ? Using a suitable $SCRATCH all
big files should go to a local disk.
PPS: Check the input sections of lapw0,1,2 for the switch to reduce further the
size of the outputX files.
If this does not help, your cluster is an "unusable" machine.
PPPS: If k-point parallel does not work, most likely also mpi will not work, because
also in this case you need to be able to write/read files reliably.

Marcos Veríssimo Alves schrieb:
> Hi all,
> 
> The setting up of the .machines file of Wien2K for a parallel run using 
> mpi is not very clear to me... I am searching the list and I do not get 
> to conclusions about it, so I am asking for your help. I'll state my 
> problem as concisely and precisely as I can.
> 
> I am still having problems with running Wien2K parallel over k-points 
> (that is, using ssh/rsh) because our cluster's AFS seems to be really 
> unstable. So I am going to try to compile Wien2K using mvapich, since 
> part of the cluster is interconnected with infiniband.
> 
> Now, the infiniband part of the cluster is composed of 16 identical 
> machines (let's call them machine1...machine16) with 4 cpus each. I 
> would like to run Wien2K in parallel over k-points but using mvapich 
> instead of ssh. The machines are assigned by a queuing system, but I 
> have already easily written a script which reads the machines file 
> assigned by the queuing system, determines the machines assigned, and 
> how many processors of each machine participate in the calculation. I 
> have a number of k-points which is not a multiple of the number of cpus 
> assigned, so I'd like to assign one k-point per processor, and the 
> remaining k-points could either be done fine-grained, or assigned 
> individually.
> 
> To be more precise, suppose I have 32 k-points and the maximum number of 
> processors I got was 9 (because all the others were busy with other 
> users' processes). Supposing that the file with the machines assigned by 
> the queuing system was:
> 
> machine1            (machine1: one processor)
> machine2
> machine2
> machine2            (machine2: three processors)
> machine3            (machine3: one processor)
> machine4
> machine4            (machine4: two processors)
> machine5
> machine5            (machine5: two prcessors)
> 
> My question is: if all processor have the same speed, would the 
> following .machines file be valid for running processes **only with 
> mpi** (no sending processes over ssh whatsoever)?
> 
> 
> #
> # Hypothetical 
> granularity:1
> extrafine:1
> 1:machine1:4 machine2:12 machine4:2 machine3:3 machine4:6 machine5: 6
> 
> I am so sorry to ask a question which must be extremely basic, but I 
> couldn't find any enlightenment in the list, and I find the example in 
> the manual very confusing... I thank you for any advice you can give me 
> with that respect.
> 
> Best regards,
> 
> Marcos
> 
> 
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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