Merge pull request #30 from AlexWendland/master

mlrose_hiive/fitness/max_k_color.py

@@ -3,7 +3,6 @@
 # Author: Genevieve Hayes (Modified by Andrew Rollings)
 # License: BSD 3 clause
 
-import numpy as np
 
 
 class MaxKColor:

mlrose_hiive/fitness/queens.py

@@ -36,9 +36,10 @@ class Queens:
     optimization problems *only*.
     """
 
-    def __init__(self):
+    def __init__(self, maximize=False):
 
         self.prob_type = 'discrete'
+        self.maximize = maximize
 
     @staticmethod
     def shift(a, num, fill_value=np.nan):
@@ -84,6 +85,8 @@ def evaluate(self, state):
 
         f_d = np.sum(state_shifts == state) // 2  # each diagonal piece is counted twice
         fitness = f_h + f_d
+        if self.maximize:
+            fitness = self.get_max_size(ls) - fitness
         return fitness
 
     def get_prob_type(self):
@@ -96,3 +99,11 @@ def get_prob_type(self):
             or 'either'.
         """
         return self.prob_type
+
+    @staticmethod
+    def get_max_size(problem_size):
+        if problem_size <= 1:
+            return 0
+        if problem_size == 2:
+            return 1
+        return 3*(problem_size-2)

mlrose_hiive/generators/queens_generator.py

@@ -5,7 +5,8 @@
 
 class QueensGenerator:
     @staticmethod
-    def generate(seed, size=20):
+    def generate(seed, size=20, maximize=False):
         np.random.seed(seed)
-        problem = QueensOpt(length=size)
+        problem = QueensOpt(length=size, maximize=maximize)
         return problem
+

mlrose_hiive/opt_probs/max_k_color_opt.py

@@ -39,6 +39,8 @@ def __init__(self, edges=None, length=None, fitness_fn=None, maximize=False,
         else:
             self.source_graph = source_graph
 
+        self.stop_fitness = self.source_graph.number_of_edges() if maximize else 0
+
         fitness_fn.set_graph(self.source_graph)
         # if none is provided, make a reasonable starting guess.
         # the max val is going to be the one plus the maximum number of neighbors of any one node.
@@ -58,4 +60,4 @@ def __init__(self, edges=None, length=None, fitness_fn=None, maximize=False,
         self.set_state(state)
 
     def can_stop(self):
-        return int(self.get_fitness()) == 0
+        return int(self.get_fitness()) == self.stop_fitness

mlrose_hiive/opt_probs/queens_opt.py

@@ -24,7 +24,9 @@ def __init__(self, length=None, fitness_fn=None, maximize=False,
         self.length = length
 
         if fitness_fn is None:
-            fitness_fn = Queens()
+            fitness_fn = Queens(maximize=maximize)
+
+        self.stop_fitness = Queens.get_max_size(length) if maximize else 0
 
         self.max_val = length
         crossover = UniformCrossOver(self) if crossover is None else crossover
@@ -36,4 +38,4 @@ def __init__(self, length=None, fitness_fn=None, maximize=False,
         self.set_state(state)
 
     def can_stop(self):
-        return int(self.get_fitness()) == 0
+        return int(self.get_fitness()) == self.stop_fitness