Fix move and variable timestep


I noticed that it is impossible to use fix move linear with fix dt/reset. Is there some fundamental issue here or is it just not programmed?

Looking at the source code, I understand why it can’t work as it is, but it should be fairly easy to make it compatible. For example, by changing line:

to something like:
x[i][0] += vx*update->dt

I think for the most part, the reason is that fix move predates fix dt/reset and thus far nobody wanted to use both at the same time or people have been using the alternative approach given below.

There is a subtle difference, but a) what you propose to do can already be implemented with fix nve and fix setforce 0 0 0 or similar and b) there is a difference in the exact position at the end of the run because a) (and your proposed change) will accumulate errors from floating-point truncation.

You are absolutely right! I can’t believe I have missed this option with fix setforce. Thank you for your help. (: