Added iterations and observations of interactions

src/critters.py

@@ -29,8 +29,25 @@ def __init__(self, strategy):
         self.name = "Critter_%d" % Critter.number_of
 
     def interact(self, other_critter):
+        '''Interact with another critter
+        >>> c1 = Critter(CheatStrategy())
+        >>> c2 = Critter(CheatStrategy())
+        >>> c1.interact(c2)
+        0
+        '''
         return self.strategy.interact(other_critter)
 
+    def observe_interaction(self, critter1, critter1_action, 
+                            critter2, critter2_action):
+        '''
+        take into account an interaction
+        >>> c1 = Critter(CheatStrategy())
+        >>> c2 = Critter(CheatStrategy())
+        >>> c1.observe_interaction(c1,0,c2,0)
+        '''
+        self.strategy.observe_interaction(critter1, critter1_action, 
+                                          critter2, critter2_action)
+
     def add_food(self, food_amount):
         '''
         Adds food to the critter
@@ -69,7 +86,7 @@ def interact(self, other_agent):
 
     def observe_interaction(self, agent1, agent1_action, agent2, agent2_action):
         '''
-        provides information to the agent about what transpired in an interaction.
+        provides information to the strategy about what transpired in an interaction.
         Does not return anything
         >>> strategy = AbstractStrategy()
         >>> strategy.observe_interaction(Critter(None), 1, Critter(None), 0)

src/main.py

@@ -4,10 +4,10 @@
 
 @author: ben
 '''
-import sys, getopt
+import sys, getopt, world
 
 def main(argv):
-    name = 'world'
+    world_to_run = 'PrisonersDilemma'
     try:
         opts, args = getopt.getopt(argv, 'h','--help')
 
@@ -18,15 +18,24 @@ def main(argv):
         if opt in ('-h','--help'):
             usage()
             sys.exit()
-    name = "".join(args) or name
-    print "Hello, %s" % name
-
+    world_to_run = "".join(args) or world_to_run
+
+    print "running world %s" % world_to_run
+
+    instantiate_world(world_to_run).run()
+
 
 def usage():
     '''prints usage instructions'''
-    print('Usage: main.py [name]')        
+    print('Usage: main.py [world]')        
+
+def instantiate_world(name_of_world):
+    '''instantiates the named world (class = world.[name_of_world]World)'''
+    return world.PrisonersDilemmaWorld()
+
 
 if __name__ == '__main__':
     main(sys.argv[1:])
 
+
 

src/world.py

@@ -0,0 +1,135 @@
+'''
+Created on May 21, 2011
+
+@author: bendavies
+'''
+import critters
+
+class World(object):
+    '''
+    abstract class for defining an interface for world objects. World objects can be
+    configured and run.
+    '''
+
+    def __init__(self):
+        '''
+        Constructor
+        '''
+
+    def run(self):
+        '''
+        Runs the world with the configuration provided
+        '''
+        return 0
+
+
+class  PrisonersDilemmaWorld(World):
+    '''
+    creates a world with critters using different strategies to determine what 
+    happens when they interact; Do they cooperate or not? Based on their mutual 
+    decisions they are provided food
+    '''
+
+    def run(self):
+        '''
+        executes the world
+        >>> world = PrisonersDilemmaWorld()
+        >>> world.run() # doctest:+ELLIPSIS
+        Critter_...Critter_...
+        1:...0...200
+        2:...0...400
+        ...
+        simulation complete.
+        '''
+        NUMBER_OF_ITERATIONS = 15
+
+        #create critter population
+        sucker = critters.Critter(critters.SuckerStrategy())
+        cheater = critters.Critter(critters.CheatStrategy())
+        population = (sucker, cheater)
+
+
+        #write headers
+        print('%s\t%s' %(population[0].name, population[1].name))
+
+        #execute iterations
+        for i in range(1,NUMBER_OF_ITERATIONS + 1):
+            self.run_iteration(population)
+            print('%d:\t%d\t%d' % 
+                  (i,population[0].food,population[1].food))
+
+        #finish simulation
+        print('simulation complete.')
+
+    def run_iteration(self, population):
+        '''
+        runs a single iteration for population. The population itself is updated
+        in the course of the exection. A population is a list of critters
+        >>> world = PrisonersDilemmaWorld()
+        >>> c1 = critters.Critter(critters.CheatStrategy())
+        >>> c2 = critters.Critter(critters.CheatStrategy())
+        >>> population = (c1,c2)
+        >>> world.run_iteration(population)
+        >>> population[1].food
+        0
+
+        '''
+
+        interaction_list = \
+            [(c1,c2) for c1 in population for c2 in population if c1 < c2]
+
+        for c1, c2 in interaction_list:
+            self.interact_critters(c1,c2)
+
+
+    def interact_critters(self, critter1, critter2):
+        '''
+        executes an interaction between 2 critters. Based on their own 
+        response to the interaction, each is rewarded food (or not) based on 
+        their response
+        >>> world = PrisonersDilemmaWorld()
+        >>> c1 = critters.Critter(critters.CheatStrategy())
+        >>> c2 = critters.Critter(critters.CheatStrategy())
+        >>> world.interact_critters(c1,c2)
+        '''
+        COOPERATE_FOOD = 100
+        CHEATER_FOOD = 200
+        SUCKER_FOOD = 0
+
+        COOPERATE = critters.AbstractStrategy.COOPERATE
+        UNCOOPERATE = critters.AbstractStrategy.UNCOOPERATE
+
+
+        critter1_interaction = critter1.interact(critter2)
+        critter2_interaction = critter2.interact(critter1)
+
+        if (critter1_interaction == COOPERATE & 
+            critter2_interaction == COOPERATE):
+
+            critter1.add_food(COOPERATE_FOOD)
+            critter2.add_food(COOPERATE_FOOD)
+
+        elif (critter1_interaction == UNCOOPERATE &
+                 critter2_interaction == UNCOOPERATE):
+            #neither gets food
+            pass
+        else:
+            #one cheated the other
+            if critter1_interaction == COOPERATE:
+                #critter1 is the sucker
+                critter1.add_food(SUCKER_FOOD)
+                critter2.add_food(CHEATER_FOOD)
+            else:
+                #critter2 is the sucker
+                critter2.add_food(SUCKER_FOOD)
+                critter1.add_food(CHEATER_FOOD)
+
+        #Critters observe the outcome
+        critter1.observe_interaction(critter1,critter1_interaction,
+                                     critter2,critter2_interaction)
+        critter2.observe_interaction(critter1,critter1_interaction,
+                                     critter2,critter2_interaction)
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()