[Wien] some comments on parallel execution of wien2k

[Sergiu Arapan]

Hi,

It seems to be working. I've tested it for 
$WIENROOT/example_struct_files/cd16te15sb.struct on 1 node with 8 cpus.

Regards,
Sergiu Arapan

Robert Laskowski wrote:
> Hi,
> I agree iatm_proc_pack is "color" for MPI_Comm_split and according to the specification it should be non negative.
> The idea behind the code around line 319
>
>      if (jatom.le.nat.and.myid_vec.eq.0) then
>         iatm_proc_pack=jatom_pe
>      else if (jatom.le.nat) then
>         iatm_proc_pack=nat+npe+jatom_pe
>      else
>         iatm_proc_pack=-(nat+npe+jatom_pe)
>      endif
>
> is to extract the first processors from suncommunicators used to split eigenvectors.
> Only communicators that comes from  iatm_proc_pack=jatom_pe are used latter in the code,
> but the rest must be separated. I suggest to change this part of the code to:
>
>      if (jatom.le.nat.and.myid_vec.eq.0) then
>         iatm_proc_pack=jatom_pe
>      else if (jatom.le.nat) then
>         iatm_proc_pack=nat+npe+jatom_pe
>      else
>         iatm_proc_pack=nat+npe+jatom_pe + npe       !!!! change
>      endif
>
> I do not have openmpi installed so please test it.
>
> regards
>
> Robert
>
>  
>
>
> On Tuesday 05 January 2010, Andres Saul wrote:
>   
>> Dear wien users:
>>    I can also confirm that there is a problem with lapw2_mpi and
>> openmpi for some specific combinations of
>> the number of atoms and number of processors. The same calculations
>> with mpich or hpmpi work fine.
>>    Looking at the source files I concluded that the problem was
>> related to using a negative second argument
>> in MPI_COMM_SPLIT in line 327 of l2main.F (wien2k v9.1).
>>
>>    I have found that a simple dirty solution consisting in changing
>> line 319 from
>>          iatm_proc_pack=-(nat+npe+jatom_pe)
>> to
>>          iatm_proc_pack=10000-(nat+npe+jatom_pe)
>>    was enough to solve the problem. I my opinion the occurrence of the
>> error for a given number of atoms or specific number of processors is
>> related to the "if then else" structure around this line.
>>
>> Regards
>> Andres Saul
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>>
>>     
>
>
>
>   

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