math operation on per atom array

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1

Hello everybody,

I tried to do some math operations with arrays but it didn't work, e.g. an element-by-element-subtraction of a force array from a different force array. Is an element-by-element subtraction just possible for vectors?

Thanks a lot,
kind regards

Sebastian

2

Hello everybody,

I tried to do some math operations with arrays but it didn't work, e.g.
an element-by-element-subtraction of a force array from a different
force array. Is an element-by-element subtraction just possible for vectors?

can you provide a lammps script example, please?
it is difficult to discuss something that nobody but you can see.

thanks,
    axel.

3

Sorry,
this would be an example:

fix force_1 all store/force
fix ywalls all wall/gran/hertz/history 1 0 yplane 0 2 1
fix force_2 all store/force
variable wallforce atom f_force_1-f_force_2

thanks,
Sebastian

4

If you mean you are using the variable command with a formula
to subtract 2 arrays, that won't work. There is no syntax in
the variable command for arrays, only per-atom vectors,
e.g. vx, not v.

Steve