[Pw_forum] set_irr_sym_new error in ph.x

[Ye Luo]

Hi all,

When I performed phonon calculation in QE 5.3.0 on BGQ,
I got set_irr_sym_new
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     Error in routine set_irr_sym_new (211):
     wrong representation
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
This error doesn't appear all the time but on some specific q points in a
grid.

By comparing with the same calculation performed on x86,
I noticed that some of the eigenvalues (autoval) computed for the q points
emitting errors are quite different. So I went to check how those values
are computed. I found that the cdiagh (in PW/src/cdiagh.f90) are branched
using ZHPEV in ESSL or ZHEEV in LAPACK. So I changed the route to force the
LAPACK one and my issue disappears. Though this solution seems solve my
issue but I was not sure it address the key problem.

My library linking order is SCALAPACK ESSL LAPACK ESSL (for FFT and BLAS)
I think this is the right order for BGQ.
Since, the cdiagh is not reported at the end of pw or ph output, I guess it
takes little time during the run and I won't get any performance penalty.

Any comments or suggestions? particularly from developers.

PS: I send an email a few weeks ago and got no reply. I hope someone can
also answer these questions.
1) Any update for releasing DFT+U phonon? I saw the paper was out years ago.
2) Any ways to reduce the phonon disk I/O to 'none' similar to pw.x?
Reduce_io seems help very little during the calculation.

Best regards,
Ye

===================
Ye Luo, Ph.D.
Leadership Computing Facility
Argonne National Laboratory
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