Does anyone know how to multiply two local vectors within lammps?

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1

I grab force and dist using compute pair/local e.g.

compute fd all pair/local force dist

I now want to multiply the force per pair by the corresponding distance per pair.

[I am after the derivative of the LJ potential with respect to sigma to get its corresponding conjugate variable λ).

dU_lj/ds = -(dU_lj/dr_ij) (rij/s)

I can dump them and do it outside lammps, but it would be nice to do it within as the data set is huge for large simulations and I need the average over a run.

Thanks,
Rene

2

no, there isn't a way to do this currently - there would
need to be a local-style variable, where a formula to
do the multiplication would be stored.

Steve