Exercise on refactoring

Animate.py

@@ -0,0 +1,37 @@
+"""
+A deliberately bad implementation of [Boids](http://dl.acm.org/citation.cfm?doid=37401.37406)
+for use as an exercise on refactoring.
+"""
+
+from matplotlib import pyplot as plt
+from matplotlib import animation
+
+import numpy
+
+from parameters import*
+import boids
+
+flock=boids.boids(attraction_strength,boidproximitythreshold,matchspeed_distance,matchspeed_strength,number_of_boids)
+flock.initial_flock()
+
+
+
+
+
+figure=plt.figure()
+axes=plt.axes(xlim=(-500,1500), ylim=(-500,1500))
+
+scatter=axes.scatter([boid.xposition for boid in flock.boids],[boid.yposition for boid in flock.boids])
+
+def animate(frame):
+   flock.update_boids()
+   scatter.set_offsets(zip([boid.xposition for boid in flock.boids],[boid.yposition for boid in flock.boids]))
+
+
+anim = animation.FuncAnimation(figure, animate,
+                               frames=200, interval=50)
+
+if __name__ == "__main__":
+    plt.show()
+
+

Animate.py~

@@ -0,0 +1,37 @@
+"""
+A deliberately bad implementation of [Boids](http://dl.acm.org/citation.cfm?doid=37401.37406)
+for use as an exercise on refactoring.
+"""
+
+from matplotlib import pyplot as plt
+from matplotlib import animation
+
+import numpy
+
+from parameters import*
+import boids
+
+flock=boids.boids(attraction_strength,boidproximitythreshold,matchspeed_distance,matchspeed_strength,number_of_boids)
+flock.initial_flock()
+
+
+
+
+
+figure=plt.figure()
+axes=plt.axes(xlim=(-500,1500), ylim=(-500,1500))
+
+scatter=axes.scatter([boid.position[0] for boid in flock.boids],[boid.position[1] for boid in flock.boids])
+
+def animate(frame):
+   flock.update_boids()
+   scatter.set_offsets(zip([boid.position[0] for boid in flock.boids],[boid.position[1] for boid in flock.boids]))
+
+
+anim = animation.FuncAnimation(figure, animate,
+                               frames=200, interval=50)
+
+if __name__ == "__main__":
+    plt.show()
+
+

Boid_differences.py

@@ -0,0 +1,12 @@
+def velocity_change(velocity1,parameter1,parameter2,change_magnitude):
+   velocitynew=velocity1+(parameter2-parameter1)*change_magnitude
+   return velocitynew
+
+
+def position_difference_test(position_x1,position_x2,position_y1,position_y2,threshold):
+   if (position_x2-position_x1)**2 + (position_y2-position_y1)**2 < threshold:
+      return True
+
+def change_in_position(position,velocity,time_increment=1):
+   new_position=position+velocity*time_increment
+   return new_position

Boid_differences.py~

@@ -0,0 +1,11 @@
+def velocity_change(velocity,parameter1,parameter2,change_magnitude):
+   for i in [0,1]:
+        return  velocity[i]+(parameter2[i]-parameter1[i])*change_magnitude
+
+def position_difference_test(position1,position2,threshold):
+   if (position2[0]-position1[0])**2 + (position[1]-position1[1])**2 < threshold:
+      return True
+
+def change_in_position(position,velocity,time_increment=1):
+   for i in [0,1]:
+      return position[i]+velocity[i]*time_increment

Boid_flight.py~

@@ -0,0 +1,29 @@
+from Boid_differences import velocity_change, position_difference_test,change_in_position
+
+def fly_to_middle(boids,threshold,number_of_boids):
+    for boid in boids:
+           for j in range(number_of_boids):
+              boid['xvelocity']=velocity_change(boid['xvelocity'],boid['xposition'],boids['xposition'][j],threshold)
+              boid['yvelocity']=velocity_change(boid['yvelocity'],boid['yposition'],boids['yposition'][j],threshold)
+
+
+
+def fly_away_from_boids(boids,number_of_boids,threshold1,threshold2):
+        for boid in boids:
+           for j in range(number_of_boids):
+                        if position_difference_test(boid['xposition'],boids['xposition'][j],boid['yposition'],boids['yposition'][j],threshold1):
+				boid['xvelocity']=velocity_change(boid['xvelocity'],boids['xposition'][j],boid['xposition'],threshold2)
+				boid['yvelocity']=velocity_change(boid['yvelocity'],boids['yposition'][j],boid['yposition'],threshold2)
+
+def match_speed(boids,number_of_boids,threshold1,threshold2):
+   for boid in boids:
+       for j in range(number_of_boids):
+	   if position_difference_test(boid['xposition'],boids['xposition'][j],boid['yposition'],boids['yposition'][j],threshold1):
+	       boid['xvelocity']=velocity_change(boid['xvelocity'],boid['xvelocity'],boids['xvelocity'][j],threshold2)
+	       boid['yvelocity']=velocity_change(boid['yvelocity'],boid['yvelocity'],boids['yvelocity'][j],threshold2)
+
+
+def move_boids(boids):
+   for boid in boids:
+		boid['xposition']=change_in_position(boid['xposition'],boid['xvelocity'])
+		boid['yposition']=change_in_position(boid['yposition'],boid['yvelocity'])

Change_in_velocity.py~

@@ -0,0 +1,5 @@
+
+def velocity_change(boids,change_magnitude):
+   for boid['xposition'] in boids['xposition']:
+      boids['xvelocity']=boids['xveloctiy']+(boid['xposition']-boids['xposition'])*change_magnitude
+   return boids['xvelocity']

Update.py~

@@ -0,0 +1,12 @@
+from Boid_flight import fly_to_middle, fly_away_from_boids, match_speed, move_boids
+
+def update_boids(boids,number_of_boids,attractionstrength,boidproximitythreshold,matchspeed_distance, matchspeed_strength):
+
+
+        fly_to_middle(boids,attractionstrength/number_of_boids,number_of_boids)
+
+        fly_away_from_boids(boids,number_of_boids,boidproximitythreshold,1)
+
+        match_speed(boids,number_of_boids,matchspeed_distance,matchspeed_strength/number_of_boids)
+
+        move_boids(boids)

boid_class.py~

@@ -0,0 +1,97 @@
+import yaml
+import random
+config=yaml.load(open("config.yml")) 
+from Boid_differences import*
+import numpy
+
+
+number_of_boids=config['number_of_boids']
+boids_starting_x_position_range= config['boids_starting_x_position_range']
+boids_starting_y_position_range= config['boids_starting_y_position_range']
+boids_starting_x_velocity_range=config['boids_starting_x_velocity_range']
+boids_starting_y_velocity_range=config['boids_starting_y_velocity_range']
+
+class boid(object):
+	def __init__(self,xposition,yposition,xvelocity,yvelocity):
+	   self.xposition=xposition
+	   self.yposition=yposition
+	   self.xvelocity=xvelocity
+	   self.yvelocity=yvelocity
+
+        def random_boid(self):
+            return boid(random.uniform(*boids_starting_x_position_range),random.uniform(*boids_starting_y_position_range),random.uniform(*boids_starting_x_velocity_range),random.uniform(*boids_starting_y_velocity_range))
+
+
+
+
+
+
+class boids(object):
+
+       def __init__(self,attraction_strength,boidproximitythreshold,matchspeed_distance,matchspeed_strength,number_of_boids):
+          self.attraction_strength=attraction_strength
+          self.boidproximitythreshold=boidproximitythreshold
+          self.matchspeed_distance=matchspeed_distance
+          self.matchspeed_strength=matchspeed_strength
+          self.number_of_boids=number_of_boids
+          self.boids= [boid(0,0,0,0)]*number_of_boids
+
+       def initial_flock(self):
+
+           self.boids=[boid(0,0,0,0).random_boid() for i in range (self.number_of_boids)]
+
+       def fly_to_centre(self):
+           for boid in self.boids:
+             for member in self.boids:
+                boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,self.attraction_strength/self.number_of_boids)
+                boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,self.attraction_strength/self.number_of_boids)
+
+       def fly_away_from_boids(self):
+        for boid in self.boids:
+           for member in self.boids:
+                        if position_difference_test(boid.xposition,member.xposition,boid.yposition,member.yposition,self.boidproximitythreshold):
+				boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,1)
+				boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,1)
+
+       def match_speed(self):
+          for boid in self.boids:
+             for member in self.boids:
+	         if position_difference_test(boid.xposition,member.xposition,boid.yposition,member.yposition,self.matchspeed_distance):
+	              boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,self.matchspeed_strength/self.number_of_boids)
+		      boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,self.matchspeed_strength/self.number_of_boids)
+
+
+       def move_boids(self):
+           for boid in self.boids:
+		boid.xposition=change_in_position(boid.xposition,boid.xvelocity)
+		boid.yposition=change_in_position(boid.yposition,boid.yvelocity)
+
+       def update_boids(self,number_of_boids):
+
+
+          self.fly_to_centre(number_of_boids)
+
+          self.fly_away_from_boids(number_of_boids)
+
+          self.match_speed(number_of_boids)
+
+          self.move_boids()
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+

boids.py

@@ -1,58 +1,81 @@
-"""
-A deliberately bad implementation of [Boids](http://dl.acm.org/citation.cfm?doid=37401.37406)
-for use as an exercise on refactoring.
-"""
-
-from matplotlib import pyplot as plt
-from matplotlib import animation
+import yaml
 import random
 
-# Deliberately terrible code for teaching purposes
-
-boids_x=[random.uniform(-450,50.0) for x in range(50)]
-boids_y=[random.uniform(300.0,600.0) for x in range(50)]
-boid_x_velocities=[random.uniform(0,10.0) for x in range(50)]
-boid_y_velocities=[random.uniform(-20.0,20.0) for x in range(50)]
-boids=(boids_x,boids_y,boid_x_velocities,boid_y_velocities)
-
-def update_boids(boids):
-	xs,ys,xvs,yvs=boids
-	# Fly towards the middle
-	for i in range(len(xs)):
-		for j in range(len(xs)):
-			xvs[i]=xvs[i]+(xs[j]-xs[i])*0.01/len(xs)
-	for i in range(len(xs)):
-		for j in range(len(xs)):
-			yvs[i]=yvs[i]+(ys[j]-ys[i])*0.01/len(xs)
-	# Fly away from nearby boids
-	for i in range(len(xs)):
-		for j in range(len(xs)):
-			if (xs[j]-xs[i])**2 + (ys[j]-ys[i])**2 < 100:
-				xvs[i]=xvs[i]+(xs[i]-xs[j])
-				yvs[i]=yvs[i]+(ys[i]-ys[j])
-	# Try to match speed with nearby boids
-	for i in range(len(xs)):
-		for j in range(len(xs)):
-			if (xs[j]-xs[i])**2 + (ys[j]-ys[i])**2 < 10000:
-				xvs[i]=xvs[i]+(xvs[j]-xvs[i])*0.125/len(xs)
-				yvs[i]=yvs[i]+(yvs[j]-yvs[i])*0.125/len(xs)
-	# Move according to velocities
-	for i in range(len(xs)):
-		xs[i]=xs[i]+xvs[i]
-		ys[i]=ys[i]+yvs[i]
-
-
-figure=plt.figure()
-axes=plt.axes(xlim=(-500,1500), ylim=(-500,1500))
-scatter=axes.scatter(boids[0],boids[1])
-
-def animate(frame):
-   update_boids(boids)
-   scatter.set_offsets(zip(boids[0],boids[1]))
-
-
-anim = animation.FuncAnimation(figure, animate,
-                               frames=50, interval=50)
-
-if __name__ == "__main__":
-    plt.show()
+from Boid_differences import*
+import numpy
+from parameters import*
+
+class boid(object):
+	def __init__(self,xposition,yposition,xvelocity,yvelocity):
+	   self.xposition=xposition
+	   self.yposition=yposition
+	   self.xvelocity=xvelocity
+	   self.yvelocity=yvelocity
+
+        def random_boid(self):
+            return boid(random.uniform(*boids_starting_x_position_range),random.uniform(*boids_starting_y_position_range),random.uniform(*boids_starting_x_velocity_range),random.uniform(*boids_starting_y_velocity_range))
+
+
+
+
+
+
+class boids(object):
+
+       def __init__(self,attraction_strength,boidproximitythreshold,matchspeed_distance,matchspeed_strength,number_of_boids):
+          self.attraction_strength=attraction_strength
+          self.boidproximitythreshold=boidproximitythreshold
+          self.matchspeed_distance=matchspeed_distance
+          self.matchspeed_strength=matchspeed_strength
+          self.number_of_boids=number_of_boids
+          self.boids= [boid(0,0,0,0)]*number_of_boids
+
+       def initial_flock(self):
+
+           self.boids=[boid(0,0,0,0).random_boid() for i in range (self.number_of_boids)]
+
+       def fly_to_centre(self):
+           for boid in self.boids:
+             for member in self.boids:
+                boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,self.attraction_strength/self.number_of_boids)
+                boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,self.attraction_strength/self.number_of_boids)
+
+       def fly_away_from_boids(self):
+        for boid in self.boids:
+           for member in self.boids:
+                        if position_difference_test(boid.xposition,member.xposition,boid.yposition,member.yposition,self.boidproximitythreshold):
+				boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,1)
+				boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,1)
+
+       def match_speed(self):
+          for boid in self.boids:
+             for member in self.boids:
+	         if position_difference_test(boid.xposition,member.xposition,boid.yposition,member.yposition,self.matchspeed_distance):
+	              boid.xvelocity=velocity_change(boid.xvelocity,boid.xposition,member.xposition,self.matchspeed_strength/self.number_of_boids)
+		      boid.yvelocity=velocity_change(boid.yvelocity,boid.yposition,member.yposition,self.matchspeed_strength/self.number_of_boids)
+
+
+       def move_boids(self):
+           for boid in self.boids:
+		boid.xposition=change_in_position(boid.xposition,boid.xvelocity)
+		boid.yposition=change_in_position(boid.yposition,boid.yvelocity)
+
+       def update_boids(self):
+
+
+          self.fly_to_centre()
+
+          self.fly_away_from_boids()
+
+          self.match_speed()
+
+          self.move_boids()
+
+       def initial_data(self, data):
+
+               self.boids=[boid(data[0][i],data[1][i],data[2][i],data[3][i]) for i in range (self.number_of_boids)]
+
+
+
+
+