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Re: [lammps-users] Segmentation fault when using Kolmogorov/Crespi/z with REBO
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Re: [lammps-users] Segmentation fault when using Kolmogorov/Crespi/z with REBO


From: Srilok Srinivasan <srilok@...258...>
Date: Wed, 30 Aug 2017 09:56:56 -0500

Axel, 

Yes, I want to apply kolmogorov/crespi for each pairs of types separately. 

The syntax in your last email works without any error and I believe that is the model that I want for my system. 

Thanks a lot for your help! 

Suggestion: Updating the documentation for kolmogorov/crespi/z with the details in your last email will be useful for other lammps users in the future. 

Thanks 

On Tue, Aug 29, 2017 at 9:33 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:
after some more thinking, i believe the way you have to enter the potential is the following:

pair_style     hybrid/overlay rebo  kolmogorov/crespi/z 14.0  kolmogorov/crespi/z 14.0  kolmogorov/crespi/z 14.0
pair_coeff     * * rebo  CH.airebo  C C C C

pair_coeff     1 2 kolmogorov/crespi/z 1 CC.KC C  C NULL NULL
pair_coeff     1 3 kolmogorov/crespi/z 2 CC.KC C  NULL   C NULL
pair_coeff     3 4 kolmogorov/crespi/z 3 CC.KC NULL NULL C    C

because you want to apply the kolmolgorov/crespi term independently for these three pairs of types and not combine them.

axel.


On Tue, Aug 29, 2017 at 6:59 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:


On Tue, Aug 29, 2017 at 4:46 PM, Srilok Srinivasan <srilok@...258...> wrote:
Hi, 

I am trying to energy minimize a system of few layer graphene. The interaction between the atoms is modeled as a combination of REBO potential and Kolmogorov/crespi/z. My simulations work when there are only 2 layers of graphene. 

However, when there is more than 2 layers, I am getting a segmentation fault. I checked to see if I have made any mistakes in my code. But the documentation for Kolmogorov/crespi/z was not clear on how to use it when there are multiple layers. I just want to make sure that this is not a bug within lammps

I have attached the code (in.equil) and the data file (Gr_4layer_AB.data) along with the potential file. I am using the latest stable lammps release (Aug 11 2017). 

​you should contact the author of this pair style how to deal with this case. it looks to me as if you scenario is not considered, i.e. the pair style has no provisions for handling NULL atom types. you could avoid the segfault by using arguments "C C C C" to map all types to the only available set of types, but i have no idea, whether that will result in the correct behavior.  again, contacting the author is your best shot at getting an authoritative answer.

axel.​

 

Thanks a lot for your help. 

Regards, 


--
Srilok Srinivasan
Graduate Student
Mechanical Engineering
Iowa State University, Ames, IA


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--
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.



--
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.



--
Srilok Srinivasan
Graduate Student
Mechanical Engineering
Iowa State University, Ames, IA