Re: [QE-users] LIBXC versus internal QE functionals

2024-05-26 Thread Paolo Giannozzi 



On 5/26/24 23:20, Abdesalem Houari via users wrote:

After checking well the exchange-correlation document 
(Modules/funct.f90), my first issue seems resolved.


and the second as well: absolute energies depend upon the pseudopotentials

Paolo

I found that "pbe"   = "sla+pw+pbx+pbc" (= 
XC-001I-004I-003I-004I-000I-000I).
So the true PBE needs, not only "pbx" exchange + "pbc" correlation, but 
also "sla" exchange + "pw" correlation.


Thanks.

A. Houari


On Sunday, 26 May 2024 at 08:54:24 pm GMT+1, Abdesalem Houari via users 
 wrote:



Dear All,

I wanted to do a calculation test using PBE-functional from LIBXC and 
compare it to the internal QE one. As a test, I opted for body centered 
cubic (bcc) iron.


I'm a bit puzzled by the differences in the results.

- First, for PBE from LIBXC, following the QE user-guide on how to use 
LIBXC, I put the following input: 
*input_dft='XC-000I-000I-101L-130L-000I-000I*'. I obtained a total 
energy value of -39.08694619 Ry.


- Then, for QE internal PBE functional, after having a look to 
Modules/funct.f90 file, I deduced the PBE should be forced from the 
input as follow:**input_dft='XC-000I-000I-003I-004I-000I-000I*'.* Here I 
was quite surprised  obtaining a different value of the total energy 
-31.22123378 Ry... It seems like it is not the correct PBE ?


- When I just use NC-PP (Fe.pbe-mt_fhi.UPF) without forcing the 
input_dft, I get a similar result to LIBXC-PBE ... The same result is 
obtained also when I forced the input_dft, but including LDA-exchange 
(Slater)+correlation (PW) i.e. 
**input_dft='XC-001I-004I-003I-004I-000I-000I*'*

*
*
I'm really confused ! I**would be grateful if some could give a bit of 
explanation, on how the input_dft works exactly ? especially with 
respect to the Module/funct.f90 file which gives all the internal 
functionals.



I would also ask for another issue. It is explained in the PW manuel 
that input_dft overrides the PP. Normally, if I'm not wrong, whatever 
the kind of the PP given in the input file (PBE or other; 
norm-conserving or ultra-soft or PAW potential), the code will discard 
it and does not look at it at all when input_dft is forced.
Here also I'm confused, I forced the input_dft as: 
**input_dft='XC-001I-004I-003I-004I-000I-000I*'*, with two different PP 
(Fe.pbe-mt_fhi.UPF and Fe.pbe-spn-rrkjus_psl.0.2.1.UPF); and the total 
energies are completely different ! *

*
*
*
Thanks a lot in advance*
*

Sincerely yours.



Dr. Abdesalem HOUARI
---
Department of physics, Theoretical Physics Laboratory
University of Bejaia-06000. Algeria.
E-mail: abdeslam.hou...@univ-bejaia.dz & habds...@yahoo.fr
https://sites.google.com/site/houariabdeslam/homepage 



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effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine Italy, +39-0432-558216
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The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
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Re: [QE-users] LIBXC versus internal QE functionals

2024-05-26 Thread Abdesalem Houari via users 
Dear All,
I'm sorry, I have written my previous email in rush !After checking well the 
exchange-correlation document (Modules/funct.f90), my first issue seems 
resolved. 
I found that "pbe"   = "sla+pw+pbx+pbc" (= XC-001I-004I-003I-004I-000I-000I).So 
the true PBE needs, not only "pbx" exchange + "pbc" correlation, but also "sla" 
exchange + "pw" correlation. 

Thanks.
A. Houari
 

On Sunday, 26 May 2024 at 08:54:24 pm GMT+1, Abdesalem Houari via users 
 wrote:  
 
 Dear All,
I wanted to do a calculation test using PBE-functional from LIBXC and compare 
it to the internal QE one. As a test, I opted for body centered cubic (bcc) 
iron.
I'm a bit puzzled by the differences in the results.
- First, for PBE from LIBXC, following the QE user-guide on how to use LIBXC, I 
put the following input: input_dft='XC-000I-000I-101L-130L-000I-000I'. I 
obtained a total energy value of -39.08694619 Ry.

- Then, for QE internal PBE functional, after having a look to 
Modules/funct.f90 file, I deduced the PBE should be forced from the input as 
follow: input_dft='XC-000I-000I-003I-004I-000I-000I'. Here I was quite 
surprised  obtaining a different value of the total energy  -31.22123378 Ry... 
It seems like it is not the correct PBE ?

- When I just use NC-PP (Fe.pbe-mt_fhi.UPF) without forcing the input_dft, I 
get a similar result to LIBXC-PBE ... The same result is obtained also when I 
forced the input_dft, but including LDA-exchange (Slater)+correlation (PW) i.e. 
input_dft='XC-001I-004I-003I-004I-000I-000I'

I'm really confused ! I would be grateful if some could give a bit of 
explanation, on how the input_dft works exactly ? especially with respect to 
the Module/funct.f90 file which gives all the internal functionals.  


I would also ask for another issue. It is explained in the PW manuel that 
input_dft overrides the PP. Normally, if I'm not wrong, whatever the kind of 
the PP given in the input file (PBE or other; norm-conserving or ultra-soft or 
PAW potential), the code will discard it and does not look at it at all when 
input_dft is forced.Here also I'm confused, I forced the input_dft as: 
input_dft='XC-001I-004I-003I-004I-000I-000I', with two different PP 
(Fe.pbe-mt_fhi.UPF and Fe.pbe-spn-rrkjus_psl.0.2.1.UPF); and the total energies 
are completely different !  

Thanks a lot in advance

Sincerely yours.


Dr. Abdesalem 
HOUARI---
Department of physics, Theoretical Physics Laboratory
University of Bejaia-06000. Algeria.
E-mail: abdeslam.hou...@univ-bejaia.dz & habds...@yahoo.fr
https://sites.google.com/site/houariabdeslam/homepage

___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users  ___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users

[QE-users] LIBXC versus internal QE functionals

2024-05-26 Thread Abdesalem Houari via users 
Dear All,
I wanted to do a calculation test using PBE-functional from LIBXC and compare 
it to the internal QE one. As a test, I opted for body centered cubic (bcc) 
iron.
I'm a bit puzzled by the differences in the results.
- First, for PBE from LIBXC, following the QE user-guide on how to use LIBXC, I 
put the following input: input_dft='XC-000I-000I-101L-130L-000I-000I'. I 
obtained a total energy value of -39.08694619 Ry.

- Then, for QE internal PBE functional, after having a look to 
Modules/funct.f90 file, I deduced the PBE should be forced from the input as 
follow: input_dft='XC-000I-000I-003I-004I-000I-000I'. Here I was quite 
surprised  obtaining a different value of the total energy  -31.22123378 Ry... 
It seems like it is not the correct PBE ?

- When I just use NC-PP (Fe.pbe-mt_fhi.UPF) without forcing the input_dft, I 
get a similar result to LIBXC-PBE ... The same result is obtained also when I 
forced the input_dft, but including LDA-exchange (Slater)+correlation (PW) i.e. 
input_dft='XC-001I-004I-003I-004I-000I-000I'

I'm really confused ! I would be grateful if some could give a bit of 
explanation, on how the input_dft works exactly ? especially with respect to 
the Module/funct.f90 file which gives all the internal functionals.  


I would also ask for another issue. It is explained in the PW manuel that 
input_dft overrides the PP. Normally, if I'm not wrong, whatever the kind of 
the PP given in the input file (PBE or other; norm-conserving or ultra-soft or 
PAW potential), the code will discard it and does not look at it at all when 
input_dft is forced.Here also I'm confused, I forced the input_dft as: 
input_dft='XC-001I-004I-003I-004I-000I-000I', with two different PP 
(Fe.pbe-mt_fhi.UPF and Fe.pbe-spn-rrkjus_psl.0.2.1.UPF); and the total energies 
are completely different !  

Thanks a lot in advance

Sincerely yours.


Dr. Abdesalem 
HOUARI---
Department of physics, Theoretical Physics Laboratory
University of Bejaia-06000. Algeria.
E-mail: abdeslam.hou...@univ-bejaia.dz & habds...@yahoo.fr
https://sites.google.com/site/houariabdeslam/homepage

___
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users