[QE-users] dexx is negative with QE_6.4.1

[Dr. K. C. Bhamu]

Dear Experts,
I am running GAUPBE calculations for a FCC binary scalar relativistic case
with latest version of QE with mkl-2015 on a cluster with pseudo-dojo PPs
and SG15 ONCV.
K_POINTS {automatic}
 X X X 0 0 0            (X=12, 15).
taking converged value of ecutwfc (4meV). Beyond this criteria I am facing
memory issue.

I am getting the dexx is negative error:
Error in routine electrons (1):
     dexx is negative!  Check that exxdiv_treatment is appropriate for the
system, or ecutfock may be too low

I would like to mention two case where I encounter this error:
 1.
k_POINTS
12 12 12 0 0 0
nqx=1,2,3,6 finished well but error was occurred with nqx=4.
2.
k_POINTS
15 15 15 0 0 0
nqx=1,5 finished well but error was occurred with nqx=3.

I have looked over all the available threads on this forum and trying to
overcome this error.

To dig into the available options I would like to ask about input variables
of gaupbe.

1. exxdiv_treatment:  as per pw.x input descriptions it should be none but
the error says "exxdiv_treatment" ?
Can we use other approach to be used for treating the Coulomb potential
divergencies? I am afraid of using option other than none as the other
options are suggested for supercells.

2. By default  ecutvcut is 0.0.
Can we vary this ecutvcut with gaupbe? if yes then what is the approximate
range?


regards
Bhamu
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