fix ave/spatial question


I want to get a temperature gradient of a carbon nanotube. So I planned to divided the area (from 2A to 700A on z axis) into 50 layers and use ave/spatial to compute average temperature of each layer.

I wrote “ave/spatial 20 50 1000 z 13.96 c_kinetic file 90heatrate2-0.2.dat” An error came out, saying undefined lattice.

But when I wrote “ave/spatial 20 50 1000 z 2 13.96 c_kinetic units box file 90heatrate2-0.2.dat”. I found it actually divided the whole simulating box into so many layers with 13.96A in length.

I don’t know what to do. Thank you guys.


From the fix ave/spatial doc page:

A box value selects standard distance units as defined by the units command, e.g. Angstroms for units = real or metal. A lattice value means the distance units are in lattice spacings. The lattice command must have been previously used to define the lattice spacing. A reduced value means normalized unitless values between 0 and 1, which represent the lower and upper faces of the simulation box respectively. Thus an origin value of 0.5 means the center of the box in any dimension. A delta value of 0.1 means 10 bins span the box in that dimension.