fix store/force dump error

I am having problems dumping the output of a fix store/force

Part of input file is below and the error I receive is 'ERROR: Dump custom fix does not compute per-atom vector'
The manual page for the fix states it produces a per-atom array. Do I need to perform any operation on the fix before I out the stored forces to a dump file? What am I doing wrong in this case? I want to dump all 3 components of the array.

Thanks for your help,
Michael

I am having problems dumping the output of a fix store/force

Part of input file is below and the error I receive is 'ERROR: Dump
custom fix does not compute per-atom vector'
The manual page for the fix states it produces a per-atom array. Do I
need to perform any operation on the fix before I out the stored forces
to a dump file? What am I doing wrong in this case? I want to dump all 3
components of the array.

exactly that would have to be the problem. you have to dump each
component separately. the total force vector is not a "per atom vector",
but a "matrix". have you tried something like this?

dump 2 topfixed custom 200 forces-u.lammps.dump.gz id type f_20[1]
f_20[2] f_20[3]

axel.

Thanks for the quick reply, that's working fine now. I figured it would be something simple I was doing wrong.