[Pw_forum] Crash on wf_collect in multi-pool spin-polarized calcs

[Paolo Giannozzi]

It looks like yet another case of the usual mess with wavefunctions 
a. kept in memory, b. stored to a memory buffer, c. written to file.
With one k-point per pool we are in case a. but apparently the code
thinks to be in case b. that falls back to case c.. Does this happen
also in the spin-unpolarized case with # of k-points = # of points?

Paolo

On Wed, 2015-02-04 at 12:59 -0600, Peter Scherpelz wrote:
> Hello,
> 
> I'm hitting a crash that I've traced to a fairly particular set of 
> circumstances, and want to check if this is a known and/or reproducible 
> bug beyond what I've found.
> 
> In detail: I've been running parallelized, spin-polarized pw.x 
> calculations (scf and relax). Quantum-espresso v5.1, using the MPI 
> version on either a single node or cluster. I find that quantum espresso 
> crashes with a davcio error, during the wf_collect stage of the 
> computation, only if the number of pools I'm using is equal to the total 
> number of k-points after spin-polarization is considered (e.g., gamma 
> only with 2 pools, or 2 distinct k-point locations with 4 pools).
> 
> If I run on half that many pools, I do not get a crash. If I run on an 
> equal number of pools but double the number of k-points, I also do not 
> get a crash. If I set wf_collect to false, I also do not get a crash.
> 
> I've attached a toy model (Si crystal) that exhibits this behavior; and 
> can include the successful runs with the alternate configurations if 
> that helps.
> 
> Thanks in advance for your help!  And thanks overall to the developers 
> for the program - I'm a fairly new user and it's been working great 
> otherwise.
> 
> Best,
> Peter Scherpelz
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