[QE-users] pw_readschema_file failed retrieving input info from xml file ph.x using grid in qe-6.3-bkp and 2D cutoff

[Raphael Longuinhos Monteiro Lobato]

Hi,

Using ph.x with grid may lead to

       Reading data from directory:
       scratch/X.Y/_ph0/test.save/
       Message from routine pw_readschema_file:
       failed retrieving input info from xml file, check it !!!

and wrong results.

In more details (sorry if not too methodical ... but I tried ... spent 
all day on it):

There is no problem with Gamma calculations ... as there is no bands to 
be read from /scratch/_ph0/ ... I guess.

Single-q, out Gamma (say X Y 0 instead 0. 0. 0.): tests without grid 
(without breaking in start_irr) in qe-6.3-bkp (3D), and in qe-5.1.1 
without/with grid leads to same results (as expected).

Using grid in qe-6.3-bkp (2D):

   + using only_init true leads to the message of error above ... the 
calculations goes on as if all were all right, and the frequencies are 
all wrong at the end (after collect).

   + using only_init true and reduce_io true (thus repeating the band 
structure calculations done at only_init calculations each time ... the 
xml is not saved in /scratch/_ph0/) leads to frequencies as expected 
when comparison to without grid calculations.

Using grid in qe-6.3-bkp (3D):
   + using only_init true leads to the expected results (comparison with 
previous 3D cases).

For me, it indicates it may be a problem when reading the information of 
2D cutoff in the in /scrath/_ph0/test.save/data-file-schema.xml (same as 
/scrath/_ph0/test.xml).

The comparison between the scrathc/test.xml and /scratch/_ph0/test.xml 
when using the only_init true and reduce_io false shows indeed some 
unexpected discrepancies (e.g., from what I could get, it misses the 
fact that the scf was performed with assume isolated flag)

(note ... I use wf_collect false in the scf calculation and norm 
conserving pseudopotentials)

The above were single-q calculations. For the case of dispersion 
calculations using 2D, reading from /scratch/X.Y/test.save/ does not 
display the message. However, when reading the bands (reading from 
/scratch/X.Y/_ph0/test.q_X/test.save/data-file-schema.xml) it does 
display it (except for the 0. 0. 0. point ... in this case the bands are 
read from /scratch/test.save/ ) ... surprisingly, the calculations are 
correct ... I guess because in this case the code, somehow, does not 
miss the 2D flag, as it informs on the output of out.X.Y it is using 
2D... the question remains "what is the information it misses when 
reading the bands from xml ... and when it will lead to error on the 
results ? "

Also, a previous post 
http://lists.quantum-espresso.org/pipermail/users/2018-October/041419.html
... the celldm problem in the dyn header remains in 6.3-backports ... 
and one have to correct it by hand on the .dyn

If these are indeed unexpected error (not my ...  if someone can 
reproduce it) yet not solved (sorry if I miss the solution in older 
posts), the real problem is ... I don't have idea to help solving them 
...  although I could give it a try with some guide.

best,

-- 
Associate Professor Raphael Longuinhos Monteiro Lobato
CV:http://lattes.cnpq.br/1475483971471395.
Research Group site:http://jenainassoares2.wixsite.com/nanomat 
(Portuguese only - English version on the way)
Departamento de Fisica, Universidade Federal de Lavras
Av. Dr. Silvio Menicucci 1001, bairro Kenedy
Post office box 3037
37200-000 - Lavras, MG, Brazil