- added diversity selection

git-svn-id: http://moon:8086/svn/projects/GeneticAlgorithm@251 fda53097-d464-4ada-af97-ba876c37ca34

GeneticAlgorithm.py

@@ -1,4 +1,5 @@
 import numpy as np
+import copy
 
 class FinessEvaluator(object):
 	def __init__(self):
@@ -30,19 +31,32 @@ class Cromosome(object):
 		result = self.param[0] + self.param[1]*x + self.param[2]*x**2
 		return result[0]
 
-	def cross(self, p2):
+	def cross(self, other):
 		a = 0.5
-		param1 = (1-a)*self.param + a*p2.param
-		param2 = (1-a)*p2.param + a*self.param
+		param1 = (1-a)*self.param + a*other.param
+		param2 = (1-a)*other.param + a*self.param
 		ca = Cromosome(self.id, param1)
-		cb = Cromosome(p2.id, param2)
+		cb = Cromosome(other.id, param2)
 		return ca, cb
 
+	def diversity(self, other):
+		d = self.param - other.param
+		s = np.mean(d**2)
+		return s
+
 	def mutate(self):
 		gene = int(np.random.rand() * 3)
 		allele = int(5*(0.5 - np.random.rand()))
 		self.param[gene] += allele
 
+	def __copy__(self):
+		print('__copy__()')
+		return Cromosome(self.name)
+
+	def __deepcopy__(self, arg):
+		print('__deepcopy__({})'.format(arg))
+		return Cromosome(copy.deepcopy(self.name, arg))
+
 	def __str__(self):
 		return "Id: {}, f={:0.6f}, fitAccum={:0.6f}, param=\n{}".format(self.id, self.fitness, self.fitAccum, str(self.param))
 
@@ -95,13 +109,22 @@ class Population(object):
 
 			if p < chanceOfReproduction:
 				# 3.) Select parents
-				p1 = self.select(self.cromosomes)
+				mom = self.select(self.cromosomes)
 
-				p2 = p1
-				while(p2 == p1):
-					p2 = self.select(self.cromosomes)
+				cand = []
+				div = np.empty(0)
+				# Make diversity selection 1 of 3 candidates
+				for i in range(0,3):
+					dad = mom
+					while(dad == mom):
+						# Select returns fitter cromosomes with higher probabilty
+						dad = self.select(self.cromosomes)
+					cand.append(dad)
+					div = np.append(div, mom.diversity(dad))
 
-				ca, cb = p1.cross(p2)
+				# Use best, diverse cromosom
+				bestCand = np.argmax(div)
+				ca, cb = mom.cross(cand[bestCand])
 				newPop[count+0] = ca
 				newPop[count+1] = cb
 				count += 2