[lammps-users] fix/ave spatial

Dear all,

I am using the fix/ave spatial command to compute the average property in each layer along a particular direction.

My domain extends from 0-50 angstrom in x-direction, and 0-10 angstrom in both y and z directions. I have two different atom groups between 0-20 and 30-50 angstrom in x direction, which interact in course of the simulation in the intervening 20-30 initially vacant region.

I would like to compute the average velocity of atoms of each group by making layers along the y-direction. When I use the fix/ave spatial command, the layers are formed along the entire x-dimension. But I require layers in y-direction only between x-value extending between 20-30 angstrom.

Please suggest how should I approach this ?

If there is a region option in fix/ave spatial then this could be overcome, but I did not find any such option.

Thank you.


Fix ave/spatial could be specifed twice, once for each group.
But unless you can assign the 2 sets of atoms permanently to
the right group, that won't help. Otherwise you'd need to enhance
fix ave/spatial with a region option, as you suggest.