Problem while running NEB, neb style ‘each’ – LAMMPS General Discussion

Hello everyone
I am sorry if the question is so bacis, acutally I am facing problem while running NEB and using the file style ‘each’. The calculation don’t run with the error of ‘Illegal NEB command (src/REPLICA/neb.cpp:124)’.
I have all replicas initial configurations present in the directory and here is the simplest command I am using for neb
‘neb 0.0 0.001 1000 500 30 each sic.1 sic.2 sic.3 sic.4 sic.5 sic.6 sic.7’

I have also tried by specifying variable “variable i equal part” and neb command “neb 0.0 0.001 1000 500 50 each sic.$i”
even, I also try to run with “variable u uloop 7” and mentioning it in neb command.
can you suggest me where could be the problem.
i am facing very bad optimisation of final replica with file style final for so I am trying to be mroe confident of final geometry so I am using this file style.
please accept my best regards
Irslan Ullah Ashraf


Basic or not, there are crucial pieces of information missing here like what is the exact LAMMPS version you are using, what is the platform you are running on and – since you are using a REPLICA package command, what is the exact command line you are using, so that we see how many replica you are using.

This is incorrect and in conflict with the documentation.

What is the exact error message in this case?

That would also be incorrect.

That reasoning makes little sense.
Are you saying that if you use minimize in a standalone calculation on the final geometry, you get a different geometry than what you get with the neb command? Can you provide a minimal example demonstrating that?

FWIW, I can run the in.neb.sivac input file from the LAMMPS distribution with the following modifications:

  • in the in.neb.sivac file replace the line neb 0.0 0.01 100 100 10 final final.sivac with variable i equal part and neb 0.0 0.01 100 100 10 final $i.sivac
  • copy the file final.sivac to 2.sivac
  • create a file 1.sivac based on 2.sivac where the coordinates are in between their values in initial.sivac and 2.sivac

This input deck runs without errors and converges to the specified tolerances.

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