inizialization and databases

Concerns any physical issues arising during the setup step (-i option). This includes problems with symmetries, k/q-point sets, and so on. For technical problems (running in parallel, etc), refer to the Technical forum.

Moderator: Daniele Varsano

Re: inizialization and databases

Postby Daniele Varsano » Tue Jul 12, 2011 6:12 pm

Dear Sam,
the answer is: it depends.

It depends what do you want to calculate with this wavefunctions.
I think you can safely calculates optical properties in RPA or BSE.
Anyway there are problem for GW calculations. When calculating the
self-energy, you want to subtract the Vxc part of the ground state calculations:

<n|Sigma_x - Vxc|n> and Yambo it is not able to perform this operation:
<n|Vxc|n>.

May it is possible to ask pwscf to write this part and then ask yambo to read it
and subtract, but a little bit of coding is needed.

Cheers,

Daniele

PS: Non local exchange-correlation potential are implemented in Yambo, but unfortunately they are not
in the GPL version. Still check is needed. May be people working on that can add more information.
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: inizialization and databases

Postby samazadi » Tue Jul 12, 2011 6:15 pm

Dear Andrea

I am using yambo 3.2.3 rev.676

I didn't get any problem. I used hybrid functional to do -g n -p p calculations to find QP band-gap.
the final QP band-gap comes from PBE0 input is much more larger (about 3.5 eV) than GGA orbitals.

Cheers
Sam
*******************************************
Sam Azadi
Institute of Physical Chemistry and
Center for Computational Sciences
Johannes Gutenberg University Mainz
Staudinger Weg 9
D-55128 Mainz
Germany
azadi@uni-mainz.de
+49/(0)6131/39-26844
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Re: inizialization and databases

Postby Daniele Varsano » Tue Jul 12, 2011 6:20 pm

Dear Sam,
Careful!!! this is the calculation you can't do starting from wavefunctions calcualated by hybrid functionals,
for the reason I explained you above.

Cheers,

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: inizialization and databases

Postby samazadi » Tue Jul 12, 2011 6:40 pm

Dear Daniele

Thanks for your explanation. So, I got wrong results !
I have to say I waste 4 days to get this wrong results :-)
But, as Andrea said, it might be better that Yambo stops in such case.
By the way, this problem doesn't detract from Yambo value.
Thank you again for your answer.

Cheers
Sam
*******************************************
Sam Azadi
Institute of Physical Chemistry and
Center for Computational Sciences
Johannes Gutenberg University Mainz
Staudinger Weg 9
D-55128 Mainz
Germany
azadi@uni-mainz.de
+49/(0)6131/39-26844
samazadi
 
Posts: 21
Joined: Fri Apr 15, 2011 11:24 am
Location: Mainz, Germany

Re: inizialization and databases

Postby samazadi » Tue Jul 19, 2011 1:10 pm

Dear Daniele

Some of my Yambo calculations take long time, about 6-7 days.
But the max run time of the cluster I am using, is 5 days.
Is there any checkpoint restart facility in Yambo ?
I appreciate any idea to solve this problem.

Cheers
Sam
*******************************************
Sam Azadi
Institute of Physical Chemistry and
Center for Computational Sciences
Johannes Gutenberg University Mainz
Staudinger Weg 9
D-55128 Mainz
Germany
azadi@uni-mainz.de
+49/(0)6131/39-26844
samazadi
 
Posts: 21
Joined: Fri Apr 15, 2011 11:24 am
Location: Mainz, Germany

Re: inizialization and databases

Postby Daniele Varsano » Tue Jul 19, 2011 4:25 pm

Dear Sam,
yes there are some possibility to restart calculations,
what kind of calculations are you doing?
You can restart surely the excitonic matrix (Bethe Salpeter) construction, and calculation
of the screening (plasmon-pole) for the GW.

Cheers,

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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Daniele Varsano
 
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Re: inizialization and databases

Postby samazadi » Wed Jul 20, 2011 8:35 am

Dear Daniele

Thank you for reply. I am doing GW calculations with plasmon-pole approximation (-g n -p p)
Would you please tell me how can I restart GW calculations ?
Thanks in advance.

Cheers
Sam
*******************************************
Sam Azadi
Institute of Physical Chemistry and
Center for Computational Sciences
Johannes Gutenberg University Mainz
Staudinger Weg 9
D-55128 Mainz
Germany
azadi@uni-mainz.de
+49/(0)6131/39-26844
samazadi
 
Posts: 21
Joined: Fri Apr 15, 2011 11:24 am
Location: Mainz, Germany

Re: inizialization and databases

Postby Daniele Varsano » Wed Jul 20, 2011 9:07 am

Dear Sam,
I'm not totally sure, but running the same input on the interrupted calculation,
Yambo should recognize it and continue it from where it was interrupted.

Cheers,

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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