situations in graphene system

Asked by Jui-Cheng Kao on 2019-09-23

Hi all

Recently, I tried to study material properties of graphene ,so I used BigDFT to
calculate it. However, I have trouble with testing graphene model. There are
some confusing situations.

First, in my understanding, the lattice constant of graphene is roughly 2.468A.
However, I found the lattice constant of graphene in BigDFT tests folder is
2.468*R2 which is larger than regular value. Second ,I used the graphene.yaml(60 atoms)
in BigDFT's test example to extend to 2160 atoms for calculating, it is successful
to run on our machine (one node). But if we use the lattice constant of 2.468 A,
we can only run a graphene system with ~500 C atoms. Above situations are all
in the linear scaling method. I test on same machine ,but I don't know why 2160
carbon atoms could be run, and changing the lattice constant ~500 carbon atoms
could not. The error message in ~500 atoms' case shows that "segmentation fault

I would like to know what reasons caused those situations, anyone could solve my
question? Besides, may someone tell what key parameters are.

thanks :))

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Jui-Cheng Kao
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Jui-Cheng Kao (juichengkao) said :

I have found that what is the problem. It is just a misunderstanding.

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Jui-Cheng Kao (juichengkao) said :

I have found the solution. Thanks for all the developers of BigDFT and researchers.