[Pw_forum] Pw_forum Digest, Vol 24, Issue 58

[Lorenzo Paulatto]

In data 29 giugno 2009 alle ore 18:47:11, leila salimi  
<l.salimi at ph.iut.ac.ir> ha scritto:
> from ewald : error #         1
>      optimal alpha not found
>
> what should I do now?

 From what I can see, it looks like the xlf version of function erfc is not  
working as it should, or at least as we expect it to. It may take a while  
before it is possible to fix or workaround the problem in an "official"  
way.

For now, I can propose this other temporary workaround:
1. put the line you've removed from Makefile back in there, so that the  
QE-internal version of erfc is compiled,
2. open include/f_defs.h and add the following line (it does not matter  
where):
#define erfc erfc_qe
3. open PW/ewald.f90 and add the following line at the very beginning:
#include "f_defs.h"
4. add the same line also at the beginning of flib/erf.f90
4. recompile

This shall be enough for now (not for car-parrinello, though).

I'm not sure why you're having this weird problem, I've personally  
compiled QE on SP5 and SP6 machines, using the xlf compiler without any  
such problem (although editing make.sys by hand). Can you please attach  
you copy of make.sys (from the QE source directory)?

best regards

-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
www:   http://people.sissa.it/~paulatto/

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