[Pw_forum] segmentation faults in pwcond.x

[Lex Kemper]

Hey everyone,

To address one part of this question, I kept track of the memory used 
by pwcond while working on a large system. The error below (assuming 
it's the same one I have) is not RAM related, or at least was not in 
my case. I've tried different compilers/libraries, including the ones 
Dr. Stewart used.

Lex Kemper
Ph. D. student
Department of Physics
University of Florida

Derek Stewart wrote:
> Hi everyone, 
> 
> I am trying to do some calculations with pwcond to determine the complex 
> band structure for a fairly large unit cell structure (22 atoms).  I am 
> using QE version 4.0.4 compiled with the intel compilers (ifort & icc v10.1, 
> mkl 10.0.4) in parallel with lam-mpi 7.1.4.  I have no problem running the 
> scf calculation. 
> 
> However, my pwcond calculation crashes after printing out the atomic 
> positions and the following lines: 
> 
>         k(    1) = (   0.0000000   0.0000000), wk =   1.0000000 
> 
>  ngper, shell number =          951         256
>  ngper, n2d =          951         212
> forrtl: severe (174): SIGSEGV, segmentation fault occurred
> Image              PC        Routine            Line        Source
> Stack trace terminated abnormally.
> forrtl: severe (174): SIGSEGV, segmentation fault occurred
> Image              PC        Routine            Line        Source 
> 
> The run was done in parallel over 10 processors.  I have set the stack as 
> unlimited. 
> 
> Looking back through the pwscf archive, it appears that other people have 
> run into segmenation faults at a similar point in their calculation.  It was 
> mentioned that pwcond performs a diagonilization over a non-symmetric matrix 
> that occasionally crashes.  Has this issue been resolved?  Also, are there 
> problems with larger systems for pwcond and total RAM required? 
> 
> All my parameters for the pwcond input file are similar to those used in 
> example12. 
> 
> Any suggestions would be greatly appreciated! 
> 
> Thanks, 
> 
> Derek 
> 
> 
> ################################
> Derek Stewart, Ph. D.
> Scientific Computation Associate
> http://www.people.cornell.edu/pages/das248/
> 250 Duffield Hall
> Cornell Nanoscale Facility (CNF)
> Ithaca, NY 14853
> stewart (at) cnf.cornell.edu
> (607) 255-2856
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