chunk properties mathematical operations

hi all,

I am trying to calculate thermal conductivity of water using green kubo method. for that I have to calulate potential energy, kinetic energy and velocity of molecule. I used chunk command for that. now I need to do mathamatical operations like multiplication , addtition with these vectors. I tried with variable command. but its not clear in documentation how to do this operation using variable command. Anybody having idea about this?

There is no code in LAMMPS currently to invoke formulas

on global vectors (as opposed to per-atom vectors which can

be done with atom-style varaibles). Doing so would require

new coding for either vector-style variables or augmenting

the compute reduce command. Neither would be simple.

It might be possible to do what you want with embedded Python,

via the python command, since the Python code can callback

to the chunk computes that have calculated the global

vectors and access their values.


Just added a new vector-style variable which produces a global vector,
see the variable doc page.

It can be used as input to various other commands, like:

compute slice, fix ave/correlate, fix ave/histo, fix ave/time,

fix vector, thermo_style custom.

So you can try it out for your problem …