## Re: question about Netlogo syntax

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• Thank you -- this really helped!!
Message 1 of 4 , Nov 30, 2010
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Thank you -- this really helped!!

--- In netlogo-users@yahoogroups.com, James Steiner <gregortroll@...> wrote:
>
> Well, for this we need a couple things:
>
> IN-RADIUS lets us make an agentset of the agents in a certain radius
>
> OF lets us make another agent (or set of agents) do a calculation for us,
> and give us the answer.
>
> When OF is used with a set of agents, the result is a list of the results.
>
> MEAN lets us get the arithmetic mean (aka the Average) of the elements of a
> list
>
> So, lets throw all that up in the air and see what happens:
>
> let circle-turtles other ( turtles in-radius 5)
> let avg-xvalue mean [ xvalue ] of circle-turtles
> set xvalue ( xvalue + mean-xvalue) / 2
>
> And there you go.
>
> Now. One problem.
>
> If all the turtles are doing this... and since turtles really do things one
> at a time, not all at once, some turtles will have already changed their
> xvalue before other turtles... so some turtles new xvalue will include other
> turtles new xvalue, not the old xvalue!! AUGH!
>
> So, the trick here is to give the turtles another variable, where they can
> stash the NEW xvalue, until all turtles have completed the calculation. Then
> all the turtles can apply the new xvalue at once.
>
> ;; assumes turtles-own [ xvalue new-xvalue ]
> [ set new-xvalue (x-value + mean [ xvalue ] of (other (turtles in-radius
> 5)))
> ]
> [ set xvalue new-xvalue
> ]
>
> Voila!
>
> ~~James
> www.turtlezero.com
>
>
> On Sat, Nov 27, 2010 at 3:26 PM, LMS <lmsc20012@...> wrote:
>
> > ... trying to use variables of neighbors to update my turtle's variable,
> > and need help with syntax (including brackets and spaces) -
> >
> > what I want to do for variable named XVALUE:
> >
> > update each turtle's XVALUE to include [(starting XVALUE + <average of the
> > XVALUES of neighbors in a radius of 5>) divided by 2]
> >
> > -- thanks in advance,
> > LMS
> >
>
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