问题
I need to find the minimum distance between patches in front of my agent to a certain patch (goal), in order to select the patch that would create the most optimal (shortest) path. The primitive distance only requires one argument so I can't use it as is for this function.
回答1:
The distance primitive only requires one argument, yes, but it is a "patch or turtle primitive": it must be run in the context of a particular agent by "asking" it for its distance to another, so you can think of the context in which it run as another argument.
If you want to know the distance between patch 0 0 and patch 1 1, you can write:
ask patch 0 0 [ show distance patch 1 1 ]
or, likely more useful:
[ distance patch 1 1 ] of patch 0 0
来源：https://stackoverflow.com/questions/15998359/how-can-i-compute-the-distance-between-two-patches