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ProfessorHelloKittyNr1
ProfessorHelloKittyNr1

Reputation: 189

NetLogo two kinds of self-reference

I want to add an agenset of turtles to the variable TurtlesICanSee of a certain turtle that depends on that turtles properties. For instance, in one application I want to add only the turtle itself to TurtlesICanSee, in another application I want to add the two turtles (if there are any) with adjacent who-numbers (the turtle's own who-number + or - 1).

If I can figure out the first application by using who-numbers I think I can extend that to second application. However, I cannot figure out the first.

I tried

ask turtles [ set TheTurtlesICanSee turtles with [who = ([who] of self)] ]

but this fills the TheTurtlesICanSee of each turtle with every turtle.

I think I understand why; NetLogo thinks that I want every turtle x that has the same who-number as itself (x), i.e. every turtle. But I don't. For every turtle x I want every turtle y that has the same who-number as x.

Can anyone help me with this? Note that the solution that I need to the first application is one that can be generalized to the second. So not any way of adding a turtle to one of its own variables will do. I need a form of self-reference involving who (or a good argument against doing it this way I guess, but preferably the former).

Upvotes: 2

Views: 969

Answers (1)

Seth Tisue
Seth Tisue

Reputation: 30453

Your code needs only a slight alteration to work, as follows:

ask turtles [ set TheTurtlesICanSee turtles with [who = [who] of myself] ]

Note the substitution of myself for self; http://ccl.northwestern.edu/netlogo/docs/dictionary.html#myself has an explanation of the difference.

But actually there's no need to involve who numbers. It's almost never necessary to use who numbers in NetLogo; there's almost always a simpler, more direct solution. A simpler solution is:

ask turtles [ set TheTurtlesICanSee turtles with [self = myself] ]

But actually it isn't necessary to use with at all. We can use turtle-set to build the desired agentset directly:

ask turtles [ set TheTurtlesICanSee (turtle-set self) ]

This is the solution I would recommend, for clarity and brevity, but also because it will run faster, since it doesn't involve iterating over the set of all turtles, as the with-based solutions do.

Upvotes: 5

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