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I'm creating clusters of agents using the nw extension weak-component-clusters. It produces a list of agentsets.

My first goal is to calculate the average xcor and ycor of each of those agentsets in the list. I can use map to count the number of agents in each agentset, but I can't map mean [xcor]

Example:

clear-all
create-turtles 5
ask turtle 0 [ create-link-with turtle 1 ]
ask turtle 0 [ create-link-with turtle 2 ]
ask turtle 3 [ create-link-with turtle 4 ]

let clusters nw:weak-component-clusters ; create list of agentsets
; output: [(agentset, 2 turtles) (agentset, 3 turtles)]

map count clusters ; Works
;output: [2 3]

map mean [xcor] clusters ; Does not work
;output: Expected a literal value

Secondary question: I will be calculating the distance between the clusters next and I was wondering if there was an extension or function that I could use instead of just using the distance between two points formula.

Sunderam Dubey
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Yaser Baqi
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1 Answers1

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The problem is in the usage of your map function. As long as you are doing a very simple calculation (like for example your counting) map function list is sufficient. But when you want to calculate your mean xcor, you will need to add some anonymous procedure syntax.

map [ list-item -> function list-item ] list

In this case, you define a variable name that will be used for all the items of the list. This variable name is on the left of the ->. On the right side of the ->, you add a function utilising that variable. This function will then be applied to every item of the initial list, as you already know from map.

In your case, that gives us:

map [a-cluster -> mean [xcor] of a-cluster] clusters

Standard netlogo has a function for calculating the distance between agents (distance) and the distance between an agent and a point (distancexy) but no function for a distance between points. That said, the mathematical formula is simple so you could easily write your own function for that using to-report

LeirsW
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