Syntax:
compute ID group-ID variable/atom name
Examples:
compute 1 flow variable/atom myVar
Description:
Define a computation that calculates a formula for each atom in the group. The resulting values can be accessed by any command that uses per-atom computes, e.g. the dump custom command or fix ave/spatial command or fix ave/atom command.
The formula is defined by the variable atom command. A variable of style atom can access properties of the system, such as volume or temperature, and also reference individual atom attributes, such as its coordinates or velocity.
For example, these 3 commands would compute the xy kinectic energy of atoms in the flow group and include the values in dumped snapshots of the system.
variable xy atom mult(0.5,add(mult(vx[],vx[]),mult(vy[],vy[]))) compute ke flow variable/atom xy dump 1 flow custom 1000 dump.flow tag type x y z c_ke
If the dump line were replaced by
fix 1 flow ave/spatial 100 1000 z lower 2.0 ke.profile compute ke
then the xy kinetic energy values would be averaged by z layer and the layer averages written periodically to the file ke.profile.
Restrictions: none
Related commands:
Default: none