How to calculate RAM for BSE

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

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Daniele Varsano
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Re: How to calculate RAM for BSE

Post by Daniele Varsano » Thu Dec 24, 2020 4:11 pm

Dear Fadil,

you can either:
1) using the iterative solver haydock in BSS_mode
2) or compile the code using the scalapack support and assign CPU in the BS_nCPU_LinAlg_DIAGO variable.

Best,

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/

Fadil
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Re: How to calculate RAM for BSE

Post by Fadil » Fri Dec 25, 2020 11:09 pm

Dear Daniele,

Since I will calculate the excitonic eigenstates I have to use the diagonalization method.
I compiled the code using the scalapack support and set BS_nCPU_LinAlg_DIAGO as different variables like 2, 8, 16, but still does not work.
You can find the report and input files in the attachment.

Best
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Dr. Fadıl İYİKANAT
ICFO-The Institute of Photonic Sciences
Barcelona-SPAIN

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Daniele Varsano
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Re: How to calculate RAM for BSE

Post by Daniele Varsano » Sat Dec 26, 2020 7:27 am

Dear Fadil,
actually, I do not understand why there are problems in diagonalizing a 20kx20k matrix in you system as you should have enough memory.
In any case you can solve iteratively using haydock and then calculate the eigenvectors of a desired number of eigenstates using the slepc libraries, you can find here some instructions.

Best,
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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