Spatial temperature profile

Dear LAMMPS users

I want to make spatial temperature profile to certain direction(z direction) for my simulation system.

To do this, at first, I set the z directional regions like bins with region command and set the dynamic groups of these and tried to compute temperatures.

However, it didn’t work because of too many groups error.

I edited the maximum number of group larger than 32 in group.cpp and tried again, but it didn’t work again.

Next, I used compute(temp/profile) command and fix(ave/spatial) command like as below,

compute mytemp all temp/profile 1 1 1 xyz 1 1 20
fix tempf all ave/spatial 100 1 1000 c_mytemp file temp.profile

but it didn’t work with illegal fix ave/spatial command.

How can I solve the problem to make temperature profile with compute and fix command?

kind regards,
Woo Cheol Jeon

Do you expect your system to have non-zero streaming velocities? If you’re not looking at a flowing system, you probably don’t need temp/profile.

If not, and if you’re using a recent (after this summer), version of LAMMPS, you need to use compute ke/atom to get your “per-atom” temperature, then use compute chunk/atom and fix ave/chunk to average it as you like.
If you’re using an older version of LAMMPS, you can use compute ke/atom and fix ave/spatial.

Dear Niall Jackson

Thank you for your kind response.

I need to see z-directional sptial temperature every steps.

My system is Al/Ni pure metal bilayer so it is not a flowing system.

If I use compute ke/atom with compute chunck/atom and fix ave/chunk, can I export temperature information for every bins and every steps?

kind regards,
Woo Cheol Jeon

fix tempf all ave/spatial 100 1 1000 c_mytemp file temp.profile
but it didn’t work with illegal fix ave/spatial command.

B/c the syntax is incorrect - see the doc page. You don’t have

dim origin delta.

Steve

If I use compute ke/atom with compute chunck/atom and fix ave/chunk, can I export temperature information for >every bins and every steps?

If by “export” you mean write the results to a file, then yes.

See the “file” option on the fix ave/chunk command.

Steve