MaxGvecs for PBE in initialization

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MaxGvecs for PBE in initialization

Postby sdwang » Mon Nov 05, 2018 7:57 am

Dear users and developers,
I used PBE in scf and nscf of PW with cutoff 80 Ry. And I generate the SAVE directory then. The yambo -i -V all gives:

setup # [R INI] Initialization
StdoHash= 40 # [IO] Live-timing Hashes
Nelectro= 32.00000 # Electrons number
ElecTemp= 0.000000 eV # Electronic Temperature
BoseTemp=-1.000000 eV # Bosonic Temperature
OccTresh=0.1000E-4 # Occupation treshold (metallic bands)
NLogCPUs=0 # [PARALLEL] Live-timing CPU`s (0 for all)
DBsIOoff= "none" # [IO] Space-separated list of DB with NO I/O. DB=(DIP,X,HF,COLLs,J,GF,CARRIERs,W,SC,BS,ALL)
DBsFRAGpm= "none" # [IO] Space-separated list of +DB to FRAG and -DB to NOT FRAG. DB=(DIP,X,W,HF,COLLS,K,BS,QINDX,RT,ELP
MaxGvecs= 68681 RL # [INI] Max number of G-vectors planned to use
and then following >yambo, in the out put r_setup, it gives
-Input file : yambo.in
| setup # [R INI] Initialization
| BoseTemp= 0.000000 eV # Bosonic Temperature
| MaxGvecs= 675 RL # [INI] Max number of G-vectors planned to use
As we see the MaxGvecs reduced from 68681 RL to 675 RL without any revision of the input of yambo -i.
My pseudo is C.pbe-mt_fhi.UPF and I changed it to ONCVPSP PBE but the results are same.
What this problem could be?

Thanks!

Shudong
S. D. Wang
IMU,HOHHOT,CHINA
E-mail: sdwang@imu.edu.cn
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Re: MaxGvecs for PBE in initialization

Postby Daniele Varsano » Mon Nov 05, 2018 11:00 am

Dear Shudong,
can you tell us what version and release are you using?

Thanks,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/
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Re: MaxGvecs for PBE in initialization

Postby sdwang » Mon Nov 05, 2018 11:04 am

Dear Daniele,
I used 4.2.4 and 4.3.0, both give the same results. I compiled 4.2.4 with double-precision and in the output MaxGvecs increase but still less than
in the input.

Best

Shudong
S. D. Wang
IMU,HOHHOT,CHINA
E-mail: sdwang@imu.edu.cn
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Posts: 202
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Re: MaxGvecs for PBE in initialization

Postby Davide Sangalli » Mon Nov 05, 2018 11:11 am

Dear Shudong,
can you please attach the report and the log file of the run. (r-setup and l-setup)
Also the file "config/report" in the yambo source, generated after compilation.

Best,
D.
Davide Sangalli, PhD
CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) and MaX Centre
http://www.ism.cnr.it/en/davide-sangalli-cv/
http://www.max-centre.eu/
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Re: MaxGvecs for PBE in initialization

Postby sdwang » Tue Nov 06, 2018 8:53 am

Dear Davide,
Attached is the file including r_setup, log_setup, yambo.in and config.log of version 4.2.2.
Note here the file is for LDA input of QE since I found it is the same situation for LDA and PBE.

Thanks!

Shudong
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S. D. Wang
IMU,HOHHOT,CHINA
E-mail: sdwang@imu.edu.cn
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Posts: 202
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Re: MaxGvecs for PBE in initialization

Postby Davide Sangalli » Thu Nov 08, 2018 11:50 pm

Dear Shudong,
indeed from your report there are in total 114127 G-vectors, but yambo prints shells only up to [S2749]:53769(0.9691E+5).
i.e. 53769 G-vectors and ~97 Ha (instead of 160 Ha for the density).

In the output I read
Code: Select all
 .-Input file : yambo.in
 | setup                          # [R INI] Initialization
 | BoseTemp= 0.000000     eV      # Bosonic Temperature
 | MaxGvecs=  53769       RL      # [INI] Max number of G-vectors planned to use

which is consistent with the report.
Yambo uses only g-vectors up to the last closed shell.
I guess the difference from 114127 to 53769 could be a problem with precision.
Probably due to precision issues it recognizes only the shells up to 96 Ha as closed.

Did you try to compile yambo with the flag "--enable-dp" ?
You specified that in the previous message. If so, can you upload the result of the setup with yambo compiled in dp ?
Notice that you also need to compile p2y in dp and re-run p2y before doing the setup.
Also please do not use version 4.2.1 but the last patchlevel: 4.2.4

I expect that dp neither will fully solve the problem, since the real solution would be to re-write the g-vectors as integers in the code ...
At least in the part which computes the shells. This is particularly problematic in systems with hexagonal cells unfortunately.

Best,
D.
Davide Sangalli, PhD
CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) and MaX Centre
http://www.ism.cnr.it/en/davide-sangalli-cv/
http://www.max-centre.eu/
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