[Wien] parallelisation problem in optic

[Peter Blaha]

You have first to understand how parallelization works in wien2k:

The file   .machines   (which should be generated automatically by a 
script which you submit to the queuing system) is used by the "lapw1" 
step to get the parallelization. At the same time, lapw1 produces a 
.processes file, which is used in other steps (like lapw2, optic,...)

When you want to regenerate this .processes file for a different set of 
processors, you can use:

x lapw1 -p -d

which will create .processes from the new .machines file.

In your case, note, however, that for the optic step you need the same 
number of k-parallel jobs, so could use a .machines of
1:node1


The command to "regenerate" a new parallelization
1:node1
1:node1
1:node1
1:node1

and you would use only ONE of your nodes.
Am 30.01.2015 um 10:31 schrieb Pavel Ondračka:
> Dear Wien2k mailing list,
>
> I'm calculating optical properties on some large systems and I'm using a
> combination of k-point and mpi parallelisation. After converging the
> calculations would like to run optics with different .machines file.
>
> Motivation behind this is for example if I run calculation with 4
> kpoints on 4 nodes with 4 cores each node, e.g. something like this:
>
> 1:node1:4
> 1:node2:4
> 1:node3:4
> 1:node4:4
>
> then for optics (which to my knowledge can't be parallelized on mpi or
> MKL level, right?) I use only 1 core on each node thus wasting CPU-hours
> of my allocation (I can only allocate a full node). In the optimal case
> I would supply a new .machines file and calculate optics just on 1 node
>
> 1:node1
> 1:node1
> 1:node1
> 1:node1
>
> however optic -p command doesn't regenerate the .machine1...x files.
>
> This is also a problem if I want to do just
>
> x lapw2 -p -fermi
> x optics -p
>
> in already converged case. This is because I'm generating my .machines
> files based on current node allocation, however neither "x lapw2 -p" nor
> "x optics -p" refresh .machine1...x files and hence I need to rerun "x
> lapw1 -p" again, just to get the right .machine1...x files, which is a
> huge waste of CPU time.
>
> One solution is of course to generate my own .machine1...x on the fly
> with some script, but this is a nuisance and error prone.
>
> Is it possible to force x script to just generate right .machine1...x
> files and do nothing else?
>
> The optimal way would be a switch, something like
>
> x -genmachines
>
> so that I can just continue with:
>
> x lapw2 -p -fermi
> x optic -p
>
> Any ideas?
>
> Best regards
> Pavel Ondračka
>
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-- 
Peter Blaha
Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671