added chapter 7 code

Chapter 7 - Money, sex and evolution/evolution/evolution.r

@@ -0,0 +1,13 @@
+library(ggplot2)
+data <- read.table("evolution.csv", header=F, sep=",")
+colnames(data) <- c('population','metabolism','vision_range')
+pdf("evolution.pdf")
+time = 1:nrow(data)
+grid.newpage()
+pushViewport(viewport(layout=grid.layout(1,2)))
+vplayout <- function(x,y) {viewport(layout.pos.row=x, layout.pos.col=y)}
+p <- qplot(time, metabolism, data=data, geom=c("point", "smooth"), main="Evolution in metabolism")
+print(p, vp=vplayout(1,1))
+p <- qplot(time, vision_range, data=data, geom=c("point", "smooth"), main="Evolution in vision range")
+print(p, vp=vplayout(1,2))
+dev.off()

Chapter 7 - Money, sex and evolution/evolution/food.rb

@@ -0,0 +1,24 @@
+class Food
+  attr_reader :quantity, :position 
+
+  def initialize(slot, p)
+    @position = p 
+    @slot = slot
+    @quantity = rand(20) + 10
+  end
+
+  def eat(much)
+    @quantity -= much
+  end
+
+  def draw
+    @slot.oval :left => @position[0], :top => @position[1], :radius => quantity, :center => true
+  end  
+
+  def tick
+    if @quantity <= 0
+      $food.delete self
+    end
+    draw
+  end
+end

Chapter 7 - Money, sex and evolution/evolution/parameters.rb

@@ -0,0 +1,27 @@
+FPS = 6
+ROID_SIZE = 6
+WORLD = {:xmax => ROID_SIZE * 100, :ymax => ROID_SIZE * 100} # boundary of the world
+POPULATION_SIZE = 50
+FOOD_COUNT = 30
+OBSTACLE_SIZE = 30
+MAGIC_NUMBER = 10 # the number of roids it will monitor
+
+SEPARATION_RADIUS = ROID_SIZE * 2 # steer to avoid crowding of flockmates
+ALIGNMENT_RADIUS  = ROID_SIZE * 35 # steer towards average heading of flockmates
+COHESION_RADIUS   = ROID_SIZE * 35 # steer to move toward average position of flockmates
+
+SEPARATION_ADJUSTMENT = 10 # how far away should roids stay from each other (small further away)
+ALIGNMENT_ADJUSTMENT = 8 # how aligned are the roids with each other (smaller more aligned)
+COHESION_ADJUSTMENT = 100 # how cohesive the roids are with each other (smaller more cohesive)
+CENTER_RADIUS     = ROID_SIZE * 10 # radius of how close to the center it stays
+MAX_ROID_SPEED = 20
+
+END_OF_THE_WORLD = 3000
+MAX_LIFESPAN = 100
+MAX_ENERGY = 100
+CHILDBEARING_AGE = 20..50
+CHILDBEARING_ENERGY_LEVEL = 15
+CHILDBEARING_ENERGY_SAP = 0.8
+
+MAX_METABOLISM = 4.0
+MAX_VISION_RANGE = ROID_SIZE * 10.0

Chapter 7 - Money, sex and evolution/evolution/roid.rb

@@ -0,0 +1,199 @@
+class Roid
+  attr_reader :velocity, :position, :energy, :uid, :sex, :lifespan, :age, :metabolism, :vision_range
+
+  def initialize(slot, p, v, id) 
+    @velocity = v # assume v is a Vector with X velocity and Y velocity as elements
+    @position = p # assume p is a Vector with X and Y as elements
+    @slot = slot
+    @energy = rand(MAX_ENERGY)
+    @uid = id
+    @sex = rand(2) == 1 ? :male : :female
+    @lifespan = rand(MAX_LIFESPAN)
+    @age = 0
+    @metabolism = rand(MAX_METABOLISM*10.0)/10.0
+    @vision_range = rand(MAX_VISION_RANGE*10.0)/10.0
+  end
+
+  def distance_from(roid)
+    distance_from_point(roid.position)
+  end
+
+  def distance_from_point(vector)
+    x = self.position[0] - vector[0]
+    y = self.position[1] - vector[1]
+    Math.sqrt(x*x + y*y)    
+  end
+
+  def nearby?(threshold, roid)
+    return false if roid === self
+    (distance_from(roid) < threshold) and within_fov?(roid)
+  end
+
+  def within_fov?(roid)
+    v1 = self.velocity - self.position
+    v2 = roid.position - self.position
+    cos_angle = v1.inner_product(v2)/(v1.r*v2.r)
+    Math.acos(cos_angle) < 0.75 * Math::PI
+  end
+
+  def draw
+    size = ROID_SIZE * @energy.to_f/50.0
+    size = 10 if size > 10
+    o = @slot.oval :left => @position[0], :top => @position[1], :radius => size, :center => true
+    o.fill = @slot.lightblue if @sex == :male
+    @slot.line @position[0], @position[1], @position[0] - @velocity[0], @position[1] - @velocity[1]    
+  end
+
+  def move
+    @delta = Vector[0,0]    
+    %w(separate align cohere muffle hungry).each do |action|
+      self.send action
+    end    
+    @velocity += @delta
+    @position += @velocity
+    fallthrough and draw    
+  end
+
+  def separate
+    distance = Vector[0,0]
+    r = $roids.sort {|a,b| self.distance_from(a) <=> self.distance_from(b)}
+    roids = r.first(MAGIC_NUMBER)
+      roids.each do |roid|
+        if nearby?(SEPARATION_RADIUS, roid)
+          distance += self.position - roid.position
+        end    
+      end
+    @delta += distance
+  end
+
+  # roids should look out for roids near it and then fly towards the center of where the rest are flying
+  def align
+    alignment = Vector[0,0]
+    r = $roids.sort {|a,b| self.distance_from(a) <=> self.distance_from(b)}
+    roids = r.first(MAGIC_NUMBER)
+    roids.each do |roid|
+      alignment += roid.velocity
+    end
+    alignment /= MAGIC_NUMBER
+    @delta += alignment/ALIGNMENT_ADJUSTMENT
+  end
+
+  # roids should stick to each other
+  def cohere
+    average_position = Vector[0,0]
+    r = $roids.sort {|a,b| self.distance_from(a) <=> self.distance_from(b)}
+    roids = r.first(MAGIC_NUMBER)
+    roids.each do |roid|
+      average_position += roid.position
+    end
+    average_position /= MAGIC_NUMBER
+    @delta +=  (average_position - @position)/COHESION_ADJUSTMENT
+  end
+
+  # get the roids to move around the center of the displayed world
+  def center
+    @delta -= (@position - Vector[WORLD[:xmax]/2, WORLD[:ymax]/2]) / CENTER_RADIUS
+  end
+
+  # muffle the speed of the roid to dampen the swing
+  # swing causes the roid to move too quickly out of range to be affected by the rules
+  def muffle
+    if @velocity.r > MAX_ROID_SPEED
+      @velocity /= @velocity.r 
+      @velocity *= MAX_ROID_SPEED  
+    end
+  end
+
+  def center
+    @delta -= (@position - Vector[WORLD[:xmax]/2, WORLD[:ymax]/2]) / CENTER_RADIUS
+  end
+
+  def fallthrough
+    x = case 
+    when @position[0] < 0            then WORLD[:xmax] + @position[0]
+    when @position[0] > WORLD[:xmax] then WORLD[:xmax] - @position[0]
+    else @position[0]
+    end
+    y = case 
+    when @position[1] < 0            then WORLD[:ymax] + @position[1]
+    when @position[1] > WORLD[:ymax] then WORLD[:ymax] - @position[1]
+    else @position[1]
+    end 
+
+    @position = Vector[x,y]    
+  end
+
+  # get attracted to food
+  def hungry
+    $food.each do |food|
+      if distance_from_point(food.position) < (food.quantity + @vision_range)
+        @delta -= self.position - food.position
+      end  
+      if distance_from_point(food.position) <= food.quantity + 15
+        eat food
+      end  
+    end    
+  end
+
+  def reduce_energy_from_childbirth
+    @energy = @energy * CHILDBEARING_ENERGY_SAP
+  end
+
+  # consume the food and replenish energy with it
+  def eat(food)  
+    food.eat 1
+    @energy += @metabolism 
+  end
+
+  # lose energy at every tick
+  def lose_energy
+    @energy -= 1
+  end
+
+  def grow_older
+    @age += 1
+  end
+
+  def inherit(crossover)
+    @metabolism = crossover[0]
+    @vision_range = crossover[1]
+  end
+
+  def procreate
+    if attractive and @sex == :female
+      # check for potential nearby mates
+      r = $roids.sort {|a,b| self.distance_from(a) <=> self.distance_from(b)}
+      roids = r.first(MAGIC_NUMBER)
+      roids.each do |roid|
+        if roid.attractive and roid.sex == :male
+          baby = Roid.new(@slot, @position, @velocity, 1001)
+          crossovers = [[@metabolism, @vision_range],
+                        [@metabolism,roid.vision_range],
+                        [roid.metabolism, @vision_range],
+                        [roid.metabolism,roid.vision_range]]
+          baby.inherit crossovers[rand(4)]
+          $roids << baby
+          reduce_energy_from_childbirth
+          roid.reduce_energy_from_childbirth
+        end
+
+      end      
+    end
+  end
+
+  def attractive
+    CHILDBEARING_AGE.include? @age  and @energy > CHILDBEARING_ENERGY_LEVEL
+  end
+
+  # called at every tick of time
+  def tick
+    move
+    lose_energy
+    grow_older
+    procreate
+    if @energy <= 0 or @age > @lifespan
+      $roids.delete self
+    end    
+  end
+
+end

Chapter 7 - Money, sex and evolution/evolution/utopia.rb

@@ -0,0 +1,82 @@
+require 'matrix'
+require 'csv'
+require 'enc/trans/transdb'
+require './parameters'
+require './roid'
+require './food'
+
+class Vector
+  def /(x)
+    if (x != 0)
+      Vector[self[0]/x.to_f,self[1]/x.to_f]
+    else
+      self
+    end
+  end  
+end
+
+def random_location
+  Vector[rand(WORLD[:xmax]),rand(WORLD[:ymax])]
+end
+
+def populate
+  POPULATION_SIZE.times do |i|
+    random_velocity = Vector[rand(11)-5,rand(11)-5]
+    $roids << Roid.new(self, random_location, random_velocity, i)     
+  end  
+end
+
+def scatter_food
+  FOOD_COUNT.times do
+    $food << Food.new(self, random_location)     
+  end  
+end
+
+def randomly_scatter_food(probability)
+  if (0..probability).include?(rand(100))
+    $food << Food.new(self, random_location)
+  end  
+end
+
+def write(data)
+  CSV.open('data.csv', 'w') do |csv|
+    data.each do |row|
+      csv << row
+    end
+  end  
+end
+
+Shoes.app(:title => 'Utopia', :width => WORLD[:xmax], :height => WORLD[:ymax]) do
+  background ghostwhite
+  stroke slategray
+
+  $roids = []
+  $food = []
+  data = []
+  populate
+  scatter_food
+
+  time = END_OF_THE_WORLD
+
+  animate(FPS) do 
+    randomly_scatter_food 30
+    clear do
+      fill yellowgreen      
+      $food.each do |food| food.tick; end
+      fill gainsboro      
+      $roids.each do |roid| 
+        roid.tick 
+      end
+      mean_metabolism = $roids.inject(0.0){ |sum, el| sum + el.metabolism}.to_f / $roids.size
+      mean_vision_range = $roids.inject(0.0){ |sum, el| sum + el.vision_range}.to_f / $roids.size
+      data << [$roids.size, mean_metabolism.round(2), mean_vision_range.round(2)]      
+      para "countdown: #{time}"
+      para "population: #{$roids.size}"      
+      para "metabolism: #{mean_metabolism.round(2)}"
+      para "vision range: #{mean_vision_range.round(2)}"
+    end
+
+    time -= 1
+    close & write(data) if time < 0 or $roids.size <= 0        
+  end
+end

Chapter 7 - Money, sex and evolution/inheritance/food.rb

@@ -0,0 +1,24 @@
+class Food
+  attr_reader :quantity, :position 
+
+  def initialize(slot, p)
+    @position = p 
+    @slot = slot
+    @quantity = rand(20) + 10
+  end
+
+  def eat(much)
+    @quantity -= much
+  end
+
+  def draw
+    @slot.oval :left => @position[0], :top => @position[1], :radius => quantity, :center => true
+  end  
+
+  def tick
+    if @quantity <= 0
+      $food.delete self
+    end
+    draw
+  end
+end