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Re: [lammps-users] hybrid pair_style error
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Re: [lammps-users] hybrid pair_style error


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Tue, 7 Nov 2017 10:56:24 -0500



On Tue, Nov 7, 2017 at 4:01 AM, YOHANNA Jacob Baro via lammps-users <lammps-users@lists.sourceforge.net> wrote:
yes sir, am new with lammps and gradually getting use it.
the problem am trying to solve involves the use of morethan One pair potential. can it be model without the use of 'hybrid'?

​as i already told you, i highly recommend to start with simulating (much) simpler and well understood systems first.
you are not the first person describing to be in this kind of situation who is at the same time directly starting with setting up his research project.
history has shown that - unless you are an exceptional genius - this is a doomed approach and you are bound to waste a lot of your time and the time of the people on this list. the fact, that you manage to cram so many errors in such a few lines of input script and, that you seem to be missing the understanding of some general concepts of manybody potentials and units, confirms that you are normal than anybody else here.
also you seem to believe just using cut-n-paste from random pieces of input will give you something that is somewhat working and if it won't that either LAMMPS or people on this mailing list will tell you how to fix it. that will also not work. plenty of people have tried and i don't recall anybody succeeding. instead people were quickly frustrated and upset.
the problem here is an attitude problem. the core of doing effective and correct MD is not mastering the software, but understanding the method. the hardest part of good simulations is to design the model well and have a good grasp on what is an effective descriptor of the properties you want to compute. getting a working and correct LAMMPS input is a minor issue in that respect, only that even if LAMMPS is not crashing, it does not mean, the result is useful. 

axel.
 



On Tuesday, November 7, 2017, 5:28:43 AM GMT+1, Axel Kohlmeyer <akohlmey@...24...> wrote:




On Mon, Nov 6, 2017 at 10:02 PM, YOHANNA Jacob Baro via lammps-users <lammps-users@...396...sourceforge.net> wrote:
Hi,
I got this error when running mysimulation. can somebody help please?

​there are about 5 definite errors in this little input segment​, and likely a couple more conceptual problems which point to a significant lack of experience and understanding.
i suggest you start with something simpler, where you don't need to use anything "hybrid".

since LAMMPS is a modular software, you need to make certain, that you have all modules included, that are needed for your simulations. it appears, that this is not the case here.

axel.
 

    ERROR: Illegal pair_style command (../pair_lj_cut.cpp:430)
    Last command: pair_style hybrid lj/cut 2.5 sw tersoff

here is part of my input file.

pair_style hybrid lj/cut 2.5 sw tersoff
pair_coeff       * * Ge.tersoff Ge
pair_coeff       * * p.sw P
pair_coeff       1 2 lj/cut 1.0 1.0 2.5

Jakes



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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.

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--
Dr. Axel Kohlmeyer  akohlmey@...12...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.