Zakat Charity and Wealth Distribution An Agent-Based Computational Model

globals
[
  max-grain    ;; maximum amount any patch can hold set within model (below) as 50
  gini-index-reserve
  lorenz-points
  TotalZakat ;;Zakat total per cycle zakat pls and minus
            ;;Thru slider = percent-best-land, num-people, life-expectancy-max, life-expectancy-min
  Batch ;;just for data run control, each setup will be assigned a unique random number
  totalPoordied ;;tutles died because of wealth less than zero
]
patches-own
[
  grain-here      ; the current amount of grain on this patch
  max-grain-here  ; the maximum amount of grain this patch can hold
]
turtles-own
[
  age              ; how old a turtle is
  wealth           ; the amount of grain a turtle has
  life-expectancy  ; maximum age that a turtle can reach
  metabolism       ; how much grain a turtle eats each time
  vision           ; how many patches ahead a turtle can see
  zakat
]

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to setup
  clear-all
  ;; setting seed for random numbers
  if Run# = 1 [random-seed 1151]
  if Run# = 2 [random-seed 1251]
  if Run# = 3 [random-seed 1351]
  if Run# = 4 [random-seed 1451]
  if Run# = 5 [random-seed 1551]
  ;; set global variables to appropriate values
  set max-grain 150
  set Batch random 10000
  ;; call other procedures to set up various parts of the world
  setup-patches
  setup-turtles
  update-lorenz-and-gini
  reset-ticks
  fileheaders
end 

to setup-patches
  ;; set up the initial amounts of grain each patch has
  ;; give some patches the highest amount of grain possible --
  ;; these patches are the "best land"
  ask patches
    [ set max-grain-here 0
      if (random-float 100.0) <= percent-best-land
        [ set max-grain-here max-grain
          set grain-here max-grain-here ] ]
  ;; spread that grain around the window a little and put a little back
  ;; into the patches that are the "best land" found above
  repeat 5
    [ ask patches with [max-grain-here != 0]
        [ set grain-here max-grain-here ]
      diffuse grain-here 0.25 ]
  repeat 10
    [ diffuse grain-here 0.25 ]          ;; spread the grain around some more
  ask patches
    [ set grain-here floor grain-here    ;; round grain levels to whole numbers
      set max-grain-here grain-here      ;; initial grain level is also maximum
      recolor-patch ]
end 

to recolor-patch  ;; patch procedure -- use color to indicate grain level
  set pcolor scale-color white grain-here 0 max-grain
end 

to setup-turtles
  ;; set up the initial values for the turtle variables
  set-default-shape turtles "person"
  crt num-people
    [ move-to one-of patches  ;; put turtles on patch centers
      set size 1.5  ;; easier to see
      set-initial-turtle-vars
      set age random life-expectancy ]
  recolor-turtles
end 

to set-initial-turtle-vars
  set age 0
  face one-of neighbors4
  set life-expectancy life-expectancy-min + random (life-expectancy-max - life-expectancy-min + 1)
  set metabolism 1 + random metabolism-max
  set wealth metabolism + random 50
  set vision 1 + random max-vision
end 

to recolor-turtles
  ;; Set the class of the turtles -- if a turtle has less than a third
  ;; the wealth of the richest turtle, color it red.  If between one
  ;; and two thirds, color it green.  If over two thirds, color it blue.
  let max-wealth max [wealth] of turtles
  ask turtles
    [ ifelse (wealth <= max-wealth / 3)
        [ set color red ]
        [ ifelse (wealth <= (max-wealth * 2 / 3))
            [ set color green ]
            [ set color blue ] ] ]
end 

;;; GO AND HELPERS

to go
  Set TotalZakat 0
  ask turtles [ Set Zakat 0 turn-towards-grain ]  ;; choose direction holding most grain within the turtle's vision
  harvest
  ask turtles [move-eat-age-die ]
  recolor-turtles
  ;; grow grain every grain-growth-interval clock ticks
  if ticks mod grain-growth-interval = 0 [ ask patches [ grow-grain ] ]
  update-lorenz-and-gini
  FileEntries
  ;; set-current-directory "C:\\Users\\masif\\Desktop"
  show min [wealth] of turtles
  tick
  if ticks = MaxCycles [stop]
end 

to turn-towards-grain  ;; turtle procedure
  ;; determine the direction which is most profitable for each turtle in
  ;; the surrounding patches within the turtles' vision
  set heading 0
  let best-direction 0
  let best-amount grain-ahead
  set heading 90
  if (grain-ahead > best-amount) [ set best-direction 90 set best-amount grain-ahead ]
  set heading 180
  if (grain-ahead > best-amount) [ set best-direction 180 set best-amount grain-ahead ]
  set heading 270
  if (grain-ahead > best-amount) [ set best-direction 270 set best-amount grain-ahead ]
  set heading best-direction
end 

to-report grain-ahead  ;; turtle procedure
  let total 0
  let how-far 1
  repeat vision
    [ set total total + [grain-here] of patch-ahead how-far
      set how-far how-far + 1 ]
  report total
end 

to grow-grain  ;; patch procedure
  ;; if a patch does not have it's maximum amount of grain, add
  ;; num-grain-grown to its grain amount
  if (grain-here < max-grain-here)
    [ set grain-here grain-here + num-grain-grown
      ;; if the new amount of grain on a patch is over its maximum
      ;; capacity, set it to its maximum
      if (grain-here > max-grain-here)
        [ set grain-here max-grain-here ]
      recolor-patch ]
end 

to harvest
  ;; each turtle harvests the grain on its patch.  if there are multiple
  ;; turtles on a patch, divide the grain evenly among the turtles
  ;; have turtles harvest before any turtle sets the patch to 0
  ask turtles
    [ set wealth floor (wealth + (grain-here / (count turtles-here))) ]
  ;; now that the grain has been harvested, have the turtles make the
  ;; patches which they are on have no grain
  ask turtles
    [ set grain-here 0
      recolor-patch ]
end 

to move-eat-age-die  ;; turtle procedure
  fd 1
  ;; consume some grain according to metabolism
  set wealth (wealth - metabolism)
  ;; grow older
  set age (age + 1)
; zakat procedure
if zakat_status? = true
[ zakat_distribution]

  ;; check for death conditions: if you have no grain or
  ;; you're older than the life expectancy or if some random factor
  ;; holds, then you "die" and are "reborn" (in fact, your variables
  ;; are just reset to new random values)
  if (wealth < 0) [ set-initial-turtle-vars set totalpoordied (totalpoordied + 1) ]
  if (age >= life-expectancy) [ set-initial-turtle-vars ]
end 

to zakat_distribution

  if ( count turtles with [color = red] > 0 )
  [if random 100 < Prob_Giving
    [
      if (ZakatWealthLimit = ">Mean Wealth")           [if (wealth > mean [wealth] of turtles) [Update_Zakat_And_Wealth ]]
      if (ZakatWealthLimit = "Rich Class Only")        [if (color = blue) [Update_Zakat_And_Wealth ]]
      if (ZakatWealthLimit = "Middle and Rich Class")  [if (color = green or color = blue) [Update_Zakat_And_Wealth ]]
    ]
  ]
end 

to Update_Zakat_And_Wealth
  Let TempZakat 0
  set TempZakat wealth * 0.025
  set zakat TempZakat  ;;show wealth show zakat show TempZakat
  set wealth wealth - TempZakat ;;Show wealth
  if (ZakatTakers = "Random")
  [
    ask one-of turtles with [color = red ]
    [ set zakat zakat - TempZakat ;;show wealth show zakat show TempZakat
      set wealth wealth + TempZakat ;;show wealth
    ]
  ]
  if (ZakatTakers = "Extreme")
  [
    let minW min [wealth] of turtles
    ask one-of turtles with [wealth = minW]
    [ set zakat zakat - TempZakat ;;show wealth show zakat show TempZakat
      set wealth wealth + TempZakat ;;show wealth
    ]
  ]
  set TotalZakat TotalZakat + TempZakat
end 

to update-lorenz-and-gini
  ;; this procedure recomputes the value of gini-index-reserve
  ;; and the points in lorenz-points for the Lorenz and Gini-Index plots
  let sorted-wealths sort [wealth] of turtles
  let total-wealth sum sorted-wealths
  let wealth-sum-so-far 0
  let index 0
  set gini-index-reserve 0
  set lorenz-points []

  ;; now actually plot the Lorenz curve -- along the way, we also
  ;; calculate the Gini index.
  ;; (see the Info tab for a description of the curve and measure)
  repeat num-people [
    set wealth-sum-so-far (wealth-sum-so-far + item index sorted-wealths)
    set lorenz-points lput ((wealth-sum-so-far / total-wealth) * 100) lorenz-points
    set index (index + 1)
    set gini-index-reserve
    gini-index-reserve +
    (index / num-people) -
    (wealth-sum-so-far / total-wealth)
  ]
end 

to fileheaders
  file-close-all
  set-current-directory "C:\\Users\\masif\\Desktop"
  ;;carefully [file-delete  "zakaatdata.csv"] []
  file-open "zakaatdata.csv"
  file-type "zakat_status? ,"
  file-type "Batch Run ,"
  file-type "count turtles Lower class < MaxWealth x 1/3 (Red) ,"
  file-type "count turtles Middle Class B/w MaxWealth x 1/3 and MaxWealth x 2/3 (Green) ,"
  file-type "count turtles Upper Class > MaxWealth x 2/3 (blue) ,"
  file-type "sum [wealth] Lower class ," ;; of turtles with [color = red]
  file-type "sum [wealth] Middle Class ," ;; of turtles with [color = green]
  file-type "sum [wealth] Upper Class ," ;; of turtles with [color = blue]"
  file-type "Total wealth ," ;; sum [wealth] of turtles"
  file-type "gini-index-reserve ,"
  file-type "gini ,"
  ;;file-type "lorenz-points ,"
  file-type "num-people ,"
  file-type "max-vision ,"
  file-type "metabolism-max ,"
  file-type "percent-best-land ,"
  file-type "life-expectancy-max ,"
  file-type "life-expectancy-min ,"
  file-type "grain-growth-interval ,"
  file-type "num-grain-grown ,"
  file-type "run date-and-time ,"
  file-type "cycle # ,"
  file-type "wealt of random turtle 4 ,"
  file-type "max [wealth] of turtles ,"
  file-type "min [wealth] of turtles ,"
  file-type "sum zakat +ve givers ,"
  file-type "sum zakat -ve takers ,"
  file-type "count zakat givers ,"
  file-type "count zakat takers ,"
  file-type "TotalZakat ,"
  file-type "Prob_Giving ,"
  file-type "ZakatWealthLimit ,"
  file-type "ZakatTakers ,"
  file-type "totalpoordied ,"
  file-type "avgvision_poor ,"
  file-type "avgvision_middle ,"
  file-type "avgvision_rich ,"
  file-type "avgage_poor ,"
  file-type "avgage_middle ,"
  file-type "avgage_rich ,"
  file-print ","
  file-close-all
end 

to FileEntries
  file-open "zakaatdata.csv"
  file-type zakat_status?
  file-type ","
  file-type Batch
  file-type ","
  file-type   count turtles with [color = red]
  file-type ","
  file-type   count turtles with [color = green]
  file-type ","
  file-type    count turtles with [color = blue]
  file-type ","
  file-type sum [wealth] of turtles with [color = red]
  file-type ","
  file-type sum [wealth] of turtles with [color = green]
  file-type ","
  file-type sum [wealth] of turtles with [color = blue]
  file-type ","
  file-type sum [wealth] of turtles
  file-type ","
  file-type gini-index-reserve
  file-type ","
  file-type (gini-index-reserve / num-people) / 0.5
  file-type ","
  ;;file-type lorenz-points
  ;;file-type ","
  file-type num-people
  file-type ","
  file-type max-vision
  file-type ","
  file-type metabolism-max
  file-type ","
  file-type percent-best-land
  file-type ","
  file-type life-expectancy-max
  file-type ","
  file-type life-expectancy-min
  file-type ","
  file-type grain-growth-interval
  file-type ","
  file-type num-grain-grown
  file-type ","
  file-type date-and-time
  file-type ","
  file-type ticks
  file-type ","
  ask turtle 4 [file-write wealth]
  file-type ","
  file-type max [wealth] of turtles
  file-type ","
  file-type min [wealth] of turtles
  file-type ","
  file-type sum [zakat] of turtles with [zakat > 0]
  file-type ","
  file-type sum [zakat] of turtles with [zakat < 0]
  file-type ","
  file-type count turtles with [zakat > 0] ;;not exactly rich class , probably b/c some interactions before zakat procedure changes color
  file-type ","
  file-type count turtles with [zakat < 0] ;; same as above
  file-type ","
  file-type TotalZakat
  file-type ","
  file-type Prob_Giving
  file-type ","
  file-type ZakatWealthLimit
  file-type ","
  file-type ZakatTakers
  file-type ","
  file-type totalpoordied
  file-type ","
  file-type Mean [vision] of turtles with [color = red]
  file-type ","
  file-type Mean [vision] of turtles with [color = green]
  file-type ","
  file-type Mean [vision] of turtles with [color = blue]
  file-type ","
  file-type Mean [age] of turtles with [color = red]
  file-type ","
  file-type Mean [age] of turtles with [color = green]
  file-type ","
  file-type Mean [age] of turtles with [color = blue]
  file-print ","

  file-close
end 

; Copyright 1998 Uri Wilensky
; See Info tab for full copyright and license.