[QE-users] Directory mismatch and too few bands problem in split irr calculation in ph.x

[Yujia Teng]

Dear QE forum,
I had the following 2 problems related to split irrep in ph.x calculation and wondering how to solve them. I'm following the GRID_example.


  1.  There's always directory mismatch problem of some q and irr, when I split irrep. For example, for q=2,irr=1, the tmp dir is './tmp/1.2', but in its output file, it reads other tmp directory, like './tmp/3.7'. I already set low_directory_check=.true., but this doesn't work. Sometimes, it even reports namelist error in the input file but there's no. My current solution is to write a check script to find these failed jobs and resubmit them.



  1.  There's always 'Too few bands at k point xxx' warning when I collect the result, even if I increased nbnd a lot. My system has 124 wfcs, I increased nbnd up to 256 but the warning is still present. But there's no such warning if I split q-point only or don't split. I did a convergence test w.r.t nbnd on a small q-point grid, and in my system the phonon dispersion converges (or same as no split result) at nbnd=192, although the warning is still there. I'm not sure if the result is still correct for denser parameters.


Is there a way to fully avoid the problems above? I attach some input/outputs in zip file here.

Best,
Yujia
Rutgers University.


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