Running single element using multiple element POD potential

LAMMPS LAMMPS Beginners
1

Hello,
I’m trying to run a single element (atome type 1) simulation using a POD potential that was fit on two elements database (atome type 1 and 2).
example trying to run a simulation containing only In atoms using the POD potential fit on In and P (see examples/PACKAGE/pod). I got the following error :
ERROR: Number of element to type mappings does not match number of atom types (…/pair.cpp:825)
Last command: pair_coeff * * InP_param.pod InP_coefficients.pod In P
Is there any way to avoid this error (for example in spliting the potential coefficients file into two distincts files for each element ?)
Many thanks,
Jean-Bernard

2

What if you write ?

pair_coeff * * InP_param.pod InP_coefficients.pod P

Simon

3

Thanks for your reply ; the simulation runs with your modification ! Although I’m not sure it takes the right coefficients because there is no element type identification in the coefficient file, just a succession of numbers, so lammps does’nt know how to attributes which coefficient to which element).
JB

4

It should be easy to design a simple test simulation and verify whether LAMMPS is using “ln” or “P”.

5

It is in the “param” file, though.

There are two way to deal with this situation:

  • only map elements that you want to use and for which you have atom types
  • have the full list of atom types and assign them masses and pair style parameters, but then only create atoms of the one type you want to model.
    The result should be the same. If it isn’t, there is likely a bug in the pair style.