[Wien] Parallelize Spin Up and Down

[Peter Blaha]

It is not implemented, since I'm not convinced that it is a usefull option.

a) Usually even big magnetic systems require more than 1 k-point (maybe not?)
b) On most dual processor machines I know you will not gain as much as
   expected, because the memory bus is slow and the run-time will increase if
   two lapw1 are running simultaneously.
   Instead, I tend to use a parallel goto-lib which gives a very nice
   speedup (at least for dual Xeons).

Anyway, for a shared memory machine I think it is trivial to
implement. Test the following:

Change in runsp_lapw the sections lapw1: lapw1c: lapw2: lapw2c:
and add a "background"  &  character and a    "wait" line

lapw1:
....
if ( "$so" == "-so" ) then
  total_exec	lapw1 $it0 -up $para $nohns &               <==change
else
  total_exec	lapw1 $it0 -up $para $nohns $orb &               <==change
endif
  if ($icycle >= $in1new ) then
    write_in1_lapw -dn -ql $qlimit >> $dayfile
    if($status == 0 ) cp $file.in1new $file.in1
  endif
if ( "$so" == "-so" ) then
  total_exec	lapw1 $it0 -dn $para $nohns &               <==change
else
  total_exec	lapw1 $it0 -dn $para $nohns $orb &               <==change
endif
wait                                                           <==add
...

lapw2:
if ( "$so" == "-so" ) goto lapw2c
testinput	$file.in2 error_input
total_exec	lapw2 -up $para &               <==change
total_exec	lapw2 -dn $para &               <==change
wait                                                           <==add
 
And similar in lapw1c and lapw2c sections.

In addition I'd expect that you need to comment the   testerror   statements
of the total_exec aliases.
I think that should do it. Let me know if you are successfull and it is 
usefull.

> I am running a spin-polarized job with only one k-point on a
> 2-processor machine.
> If I don't want to do fine grained parallelization, can I distribute
> spin-up and down tasks into the 2 processors so that they can run
> simultaneously (for lapw1 and
> lapw2)?
> 
> Thanks for your attention,
> Chiung-Yuan
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> 


                                      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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