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How to avoid having too many beetles on one patch in one time step?

I would like to implement certain rules into relationship between my turtles and my patches. My Patches variables are:

My turtles states are: yellow (move) -> orange (stay) -> red (infest) Patches states are: green (n_min< then number of orange turtles on one patch) pink (number of orange turtles is > n_min and < n_max) brown (no turtles)

My problem is how can I avoid to have more then n_max turtles on one patch if they are all moving at the same time and thus are targeted to same patch? How can I include the condition that "if you see that there are some turtles of color orange/red, just keep moving to find another patch? " Also, if my patch is already pink, and n_min != n_max to ask turtles to directly change its color to red?

my not working example:

globals [
  available-patch
]


patches-own [
  nmax   ; maximum nuber of turtles per patch, and change color
  nmin   ; minimum number of turtles to change patch color
  n.yellow  ; how many turtles are on the patch with yellow
  n.orange  ; how many orange (staying) turtles are on 1 patch?
]

to setup
  clear-all
  reset-ticks
  setup-patches
  setup-turtles
end

to setup-patches
  ask n-of n_patches patches [
    set pcolor green
    set nmin n_min     ; how many orange turtles can be there to set the patch to pink? 
    set nmax n_max     ; max number of orange beetles to turn the patch to brown
  ]
end

to setup-turtles
  crt n_turtles [
    set color yellow
  ]
end

to go
  tick
  ask turtles with [color = yellow ] [   ; move only yellow turtles
    move-turtles
  ]
  ask patches [  ; if n.orange = nmin, turn all turtles to red and turn patch to pink
    set n.orange count turtles-here with [color = orange]
  ] 
end

to move-turtles
   ;  if color = yellow ;and n.yellow < nmin 
   ;ifelse count other turtles-on
;   move-to one-of patches with [pcolor = green and n.orange <= nmin]
;   if [n.orange <= nmin] of patch-here [
;     set color orange  ; not to move anymore. However, the n.orange should be always less then nmin !!
;   ]
   set available-patch patches with [pcolor = green and count turtles-here with [color = orange] < 2] ; agentset 
   ifelse (count other turtles-on available-patch <= nmin) ; how to change the code for nmin here?
     [ move-to one-of available-patch                         
       set color orange
       ask patch-here [
         set n.orange count turtles-here with [color = orange]
       ]
     ]
     [ fd 2 ]
   

end

Result:

one turtle on the green patch has changed its color to orange, but I wanted 2 turtles (nmin) to find green patch and become orange. Also, the yellow turtles move next time steps just by [fd 2], the "ifelse" condition is not re-run each time step.

enter image description here

Solution

  • This code should meet my needs - keep only certain number of turtles per patch, and depending on number of turtles of certain color (nmin, nmax) per patch turn patch to pink and to brown. 

    patches-own [
  nmax   ; maximum nuber of turtles per patch, and change color
  nmin   ; minimum number of turtles to change patch color
  n.orange  ; how many orange (staying) turtles are on 1 patch?
  n.red     ; how mony infesting turtles are on the patch??
]

to setup
  clear-all 
  setup-patches
  setup-turtles
  reset-ticks
end

to setup-patches
  ask n-of n_patches patches with [pcolor = black][
    set pcolor green
    set nmin n_min     ; how many orange turtles can be there to set the patch to pink? 
    set nmax n_max     ; max number of orange beetles to turn the patch to brown
  ]
end

to setup-turtles
  crt n_turtles [
    set color yellow
  ]
end

to go 
   ; add turtles and patches by time steps, to see the effect 
  if ticks mod 5 = 0 [
    ask n-of 1 patches with [pcolor = black][
       set pcolor green
       set nmin n_min     ; how many orange turtles can be there to set the patch to pink? 
       set nmax n_max     ; max number of orange beetles to turn the patch to brown
     ]
    ]

  if ticks mod 3 = 0 [
    crt 1 [
      set color yellow
    ]
  ] 

  ask turtles with [color = yellow ] [   ; move only yellow turtles
    move-turtles
  ]
  tick 
end

to move-turtles       
    ; specify the target
    let available-patches (patches with [(pcolor = pink and count turtles-here < nmax) or   ; 
                                         (pcolor = green and count turtles-here < nmin)] )
    ; select only one patch, nmin is related to "self"

   ifelse any? available-patches ; don't work if there is <= nmin, then there are nmin + 1
     [ move-to one-of available-patches
       if pcolor = green [
         set color orange
         set n.orange (n.orange + 1)
         infest.patch   ; if there is enough turtles, turn patch to pink, turn turtles to red
       ]
       if pcolor = pink [
         set color red
         set n.red (count turtles-here with [color = red])
         kill.patch
       ]
       ]
     [ fd 1 ]
end

to infest.patch   ; change color of patch only if there is n.orange = nmin of this specific patch 
  if n.orange = nmin [
     set pcolor pink  ; patch
     ask turtles-here with [color = orange] [
        set color red ]; turtles
  ]
end

to kill.patch
  if n.red = nmax [      ; turn patch brown when red turteles on this patch are = nmax
    set pcolor brown
;    ask turtles-here with [color = red] [
;      die ]
  ]
end