Styjun

I'm checking the interaction among the properties of three types of patches by using 'one-of neighbors' command. Problem occurs when the two patches are not neighboring to each other in some cases and entity NOBODY emerges. Is there any way to avoid this. It is necessary for me to use 'one-of neighbors' command. Can I give a command stating that if Nobody is detected then the value of the property of that patch be 0.1. In my code give below the problem occurs in the interaction b/w yellow patch and red patch as in some places red is not a neighbor of yellow.

I tried writing a Nobody command it was not correct.I appreciate your advice.

globals [ k ] ; interaction constant
patches-own [ a b c d' e' eeep deep ] ; state variables of properties
 ; a is the Proportion and variety of Blend of land 
use
 ; b is the Land uses with supportiveness for 
complimentary activities
 ; c is the Vehicular and Pedestrian Intensity
 ; d is the Intensity of Nodes in urban web
 ; e' is the Frequency of Enforced Vigilance
to setup
 clear-all
 set k initial-k
 setup-patches
 reset-ticks
end
to setup-patches
 ask patches [ set pcolor yellow ] ; defines the patches as built up in an area

 ; to define yellow patches without a and b
 ask patches [ if (pycor > 1) and (pycor < 8) and (pxcor = -3 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor > 1) and (pycor < 8) and (pxcor = -2 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor < -1) and (pxcor = -10 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor < -1) and (pxcor = -9 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor < -1) and (pxcor = -5 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor < -1) and (pxcor = 2 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor < -2) and (pxcor = 6 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor > 1) and (pycor < 8) and (pxcor = 2 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = 2) and (pxcor > 8 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = -2) and (pxcor > 2 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = -3) and (pxcor > 6 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = -4) and (pxcor > 6 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = -8) and (pxcor > 6 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = -9) and (pxcor > 6 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = 7) and (pxcor > 8 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = 6) and (pxcor > 8 ) [ set pcolor 46 ] ]
 ask patches [ if (pycor = 2) and (pxcor > 2 ) and (pxcor < 6) [ set pcolor 46 ] ]

 ; to define road patches (horizontal)
 ask patches [ if pycor = 0 [ set pcolor grey ] ]
 ask patches [ if pxcor = 0 [ set pcolor grey ] ]
 ask patches [if pycor = 9 [ set pcolor grey ] ]
 ask patches [ if (pycor = 6) and (pxcor < -4 )[ set pcolor grey ] ]
 ask patches [ if (pycor = 3) and (pxcor < -4 ) [ set pcolor grey ] ]
 ask patches [ if (pycor = 4) and (pxcor > 3 ) [ set pcolor grey ] ]
 ask patches [ if (pycor = -6) and (pxcor > 7 ) [ set pcolor grey ] ]

 ; to define road patches (vertical)
 ask patches [ if (pycor > 0) and (pxcor = -10 ) [ set pcolor grey ] ]
 ask patches [ if (pycor > 0) and (pxcor = -5 ) [ set pcolor grey ] ]
 ask patches [ if (pycor < 0) and (pxcor = -7 ) [ set pcolor grey ] ]
 ask patches [ if (pycor < 0) and (pxcor = -3 ) [ set pcolor grey ] ]
 ask patches [ if (pycor < -3) and (pxcor = 4 ) [ set pcolor grey ] ]
 ask patches [ if (pycor > 3) and (pxcor = 4 ) [ set pcolor grey ] ]
 ask patches [ if (pycor > 0) and (pxcor = 7 ) [ set pcolor grey ] ]

 ; to define nodes as patches
 ask patches [ if pxcor = 0 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = 7 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = -3 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = -5 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = -7 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = -10 and pycor = 0 [ set pcolor red ] ]
 ask patches [ if pxcor = 4 and pycor = 4 [ set pcolor red ] ]
 ask patches [ if pxcor = 7 and pycor = 4 [ set pcolor red ] ]
 ask patches [ if pxcor = 7 and pycor = 9 [ set pcolor red ] ]
 ask patches [ if pxcor = 4 and pycor = 9 [ set pcolor red ] ]
 ask patches [ if pxcor = 0 and pycor = 9 [ set pcolor red ] ]
 ask patches [ if pxcor = -5 and pycor = 9 [ set pcolor red ] ]
 ask patches [ if pxcor = -10 and pycor = 9 [ set pcolor red ] ]
 ask patches [ if pxcor = -10 and pycor = 6 [ set pcolor red ] ]
 ask patches [ if pxcor = -10 and pycor = 3 [ set pcolor red ] ]
 ask patches [ if pxcor = -5 and pycor = 6 [ set pcolor red ] ]
 ask patches [ if pxcor = -5 and pycor = 3 [ set pcolor red ] ]

 ; to set intial values of properties for patches
 ask patches with [pcolor = yellow] [ set a random-float 0.9] ; initial a
 ask patches with [pcolor = yellow] [ set b random-float 0.9] ; initial b
 ask patches with [pcolor = grey] [ set c random-float 0.9] ; initial c
 ask patches with [pcolor = red] [ set d' random-float 0.9] ; initial d'
 ask patches with [pcolor = grey] [ set e' random-float 0.9] ; initial e'
end
to go
 tick
 if ticks >= 52 [ stop ]
 ask patches with [pcolor = yellow]
 [
 let fc [c] of one-of neighbors with [pcolor = grey] ; reports c of any 
 one grey patch of neighbours
 let fe' [e'] of one-of neighbors with [pcolor = grey] ; reports e' of any one grey patch of neighbours
 let fd' [d'] of one-of neighbors with [pcolor = red]; reports d' of any one red patch of neighbours
 if a < 0.1 [ set a 0.1
 if a > 0.9 [ set a 0.9 ] ]
 if b < 0.9 [ set b b + (k * a) + (k * fc) + (k * fd')
 if b > 0.9 [ set b 0.9 ] ]
 if b > 0.1 [ set b b - (k * fe')
 if b < 0.1 [ set b 0.1 ] ]
 ]
 end

I am guessing that the part of the code throwing the error is (for future reference, it is helpful if you try to focus on the part of the code that is causing the problem):

ask patches with [pcolor = yellow]
 [ let fc [c] of one-of neighbors with [pcolor = grey]
 let fe' [e'] of one-of neighbors with [pcolor = grey]
 let fd' [d'] of one-of neighbors with [pcolor = red]
 ...
 ]
 end

The primitive you want is any?. So you could rewrite:

let fc [c] of one-of neighbors with [pcolor = grey] 

as

let grey neighbors with [pcolor = grey]
let fc 0.1
if any? greys
[ set fc [c] of one-of greys ]

Alternatively

let grey neighbors with [pcolor = grey]
let fc ifelse-value any? greys
[ [c] of one-of greys ]
[ 0.1 ]

Note that neither of these pieces of code is tested.