[Q-e-developers] Debugging pw.x - a sanity check

[Pacey, Mike]

Hi folks,

I'm getting a segfault when running a parallel build of pw.x. I'm in the process of tracing the problem, but it's a slow process, so I thought I'd ask for a quick sanity check to see if I'm missing something:

The error occurs when running the example33 test, and specifically:

     from diropn : error #        10
     error opening ch4.wfc

Running this through a debugger shows that this reporting comes from io_file.f90, line 289. While that line refers to the variable "filename", the open statement before it refers to variable "tempfile", whose content is "/ch4.wfc", hence the failure. An earlier bit of code appends the "tmp_dir" from io_files.f90 onto the filename. The odd thing here is that tmp_dir is initialised to "./" not "/"

A bit more digging shows that tmp_dir gets overwritten in subroutine iosys, file input.f90, line 1027:

tmp_dir = trimcheck ( outdir ) 

The outdir variable here comes from input_parameters.f90, and it too is initialised to "./" not "/"

I'm not sure how far this particular rabbit hole goes, so before I spend another day+ trying to debug, I've decided to ask if you have any suggestions of what might be causing that value to change? Some sort of (missing) environment variable, or configuration file item? I see in the code some references to the ESPRESSO_TMPDIR environment variable, but that doesn't seem to be affecting the outcome.

Regards,
Mike.

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Dr Mike Pacey,                         Email: M.Pacey at lancaster.ac.uk
High Performance Systems Support,      Phone: 01524 510659
Information Systems Services,            Fax: 01524 594459
ISS Building, Lancaster University,
Lancaster LA1 4WA