Implement class method

src/individual.py

@@ -1,32 +1,39 @@
 from math import pow, sin, pi
 from random import Random
 
+rand = Random()
+
 
 class Individual(object):
 
     def __init__(self):
-        self.rand = Random()
-        self.x = self.rand.uniform(-100000, 100000)
-        self.y = self.rand.uniform(-100000, 100000)
-        self.fitness = 0
+        self.x = rand.uniform(-100000, 100000)
+        self.y = rand.uniform(-100000, 100000)
+
+    @classmethod
+    def from_params(cls, x, y):
+        new_individual = Individual()
+        new_individual.x = x
+        new_individual.y = y
+        return new_individual
 
     def __str__(self):
         return "x: %f\ty: %f\tfit: %f\n" %\
                (self.x, self.y, self.fitness)
 
-    def fitness_function(self):
+    def fitness(self):
         x = self.x
         y = self.y
         n = 9
-        self.fitness = pow(15*x*y*(1-x)*(1-y)*sin(n*pi*x)*sin(n*pi*y), 2)
+        return pow(15*x*y*(1-x)*(1-y)*sin(n*pi*x)*sin(n*pi*y), 2)
 
     def crossover(self, spouse):
-        temp = self.x
-        self.x = spouse.x
-        spouse.x = temp
+        one = Individual.from_params(spouse.x, self.y)
+        two = Individual.from_params(self.x, spouse.y)
+        return one, two
 
     def mutate(self):
-        if self.rand.randint(1, 10) % 2 == 0:
+        if rand.randint(1, 10) % 2 == 0:
             self.x = self.rand.random()
         else:
             self.y = self.rand.random()