Dear all lammps users.

Here part of the commands are following:

compute a mobile reduce sum c_ss[1]

compute b mobile reduce sum c_ss[2]

compute c mobile reduce sum c_ss[3]

compute d mobile reduce sum c_ss[4]

compute e mobile reduce sum c_ss[5]

compute f mobile reduce sum c_ss[6]

Now I want to use the “variable” command to define the formula {(a-b)^2+(b-c)^2+(c-a)^2+6*(d^2+e^2+f^2)}*0.5, what should I do.

Dear all lammps users.

Here part of the commands are following:

compute a mobile reduce sum c_ss[1]

compute b mobile reduce sum c_ss[2]

compute c mobile reduce sum c_ss[3]

compute d mobile reduce sum c_ss[4]

compute e mobile reduce sum c_ss[5]

compute f mobile reduce sum c_ss[6]

what you are doing here is *very* inefficient. you can do the same

operation with just one compute reduce sum command.

Now I want to use the "variable" command to define the formula {(a-b)^2+

(b-c)^2+(c-a)^2+6*(d^2+e^2+f^2)}*0.5, what should I do.

study the documentation for the variable command very carefully. it is

very detailed and has examples same as the compute reduce documentation.

axel.