Observer Command

nsum4 variable1 variable2

For each patch, takes the sum of variable1 from the non-diagonal (N,E,S,W) neighboring patches and places it in variable2. Variable should be a patch variable. Note: nsum4 must be run by the observer, even though it affects patches.

Examples:
nsum4 grass totalgrass adds up the value of grass in the non-diagonal patches and places it in totalgrass.

Related commands:
nsum diffuse