[Wien] Segmentation fault in w2w

[Niraj Aryal]

Dear w2w experts and developers,

I am using Wien2k version 19.2 in scientific linux 7.5 using intel
compilers (2018).

I am trying to wannierize f-electron system with antiferromagnetic magnetic
ordering using w2w version 2.0 in the presence of SOC.

After self-consistent calculations, these are the steps I am following for
the wannierisation:

init_w2w (to write case.klist, case.inwf, case.win etc)

 x lapw1 -up -p
 x lapw1 -dn -p
 x lapwso -up -orb -p

x w2w -so -up -p  --> segmentation fault here
x w2w -so -dn -p  --> segmentation fault here
..........

Everything works perfectly if I use small kmesh (about 100 kpoints) for the
wannierisation.
I have about 50 bands to wannierize.
When I increase the number of kpoints, w2w crashes giving segmentation
fault.

I found that w2w can write case.mmn and case.eig with no problems but the
seg fault occurred while writing case.amn.
I confirmed the following hoping that it could help in the debugging
process:

1) If I decrease the number of bands to wannierize, the number of kpoints
in the wannierisation can be slightly increased without seg fault.
2)The problem persists without -so and -p (i.e. without parallel
calculation) flag.

In my opinion, there are some hard coded array size value(s) in the w2w
program in amn/mmn subroutines which give segmentation fault when the
number of projections*bands*kpoints exceeds that value.
This was confirmed by doing calculations in a simpler system like silicon
with a large number of kpoints and bands.

I tried looking into the w2w source files and found few hard coded values.
However, I am hesitant to make changes because I am worried this could ruin
other things.

This problem is similar to the one posted last year:
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg18896.html
which was not solved.
I would greatly appreciate your suggestion/feedback regarding this problem.
You could also guide me to the right subroutines if you know the details of
the code.

Thank you.

Sincerely,
Niraj Aryal
Research Associate
Brookhaven National Lab.
Upton, NY
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