From 652e4a4b5b26c37f2e11446de7a18ee76dc67a28 Mon Sep 17 00:00:00 2001
From: SimpleArt <71458112+SimpleArt@users.noreply.github.com>
Date: Thu, 19 Nov 2020 21:28:16 -0500
Subject: [PATCH] Added function decorators

---
 .../parent_selection_methods.py               | 69 +++++++++----------
 1 file changed, 33 insertions(+), 36 deletions(-)

diff --git a/src/parent_selection/parent_selection_methods.py b/src/parent_selection/parent_selection_methods.py
index 00604c7..cd1f009 100644
--- a/src/parent_selection/parent_selection_methods.py
+++ b/src/parent_selection/parent_selection_methods.py
@@ -2,8 +2,35 @@ import random
 
 class Parent_Selection:
 
+    def __check_selection_probability(selection_method):
+        def helper(ga):
+            if 0 < ga.selection_probability < 1:
+                selection_method(ga)
+            else:
+                raise Exception("Selection probability must be greater than 0 to select parents.")
+        return helper
+
+
+    def __check_positive_fitness(selection_method):
+        def helper(ga):
+            if ga.get_chromosome_fitness(0) == 0 or ga.get_chromosome_fitness(-1) < 0:
+                raise Exception("Converted fitness values must be all positive. Consider using rank selection instead.")
+            else:
+                selection_method(ga)
+        return helper
+
+
+    def __ensure_sorted(selection_method):
+        def helper(ga):
+            ga.population.sort_by_best_fitness(ga)
+            selection_method(ga)
+        return helper
+
+
     class Rank:
 
+        @Parent_Selection._Parent_Selection__check_selection_probability
+        @Parent_Selection._Parent_Selection__ensure_sorted
         def tournament(ga):
             """
             Will make tournaments of size tournament_size and choose the winner (best fitness) 
@@ -11,14 +38,6 @@ class Parent_Selection:
             of parents selected is determined by parent_ratio, an attribute to the GA object.
             """
 
-            # Error if can't select parents
-            if ga.selection_probability <= 0:
-                print("Selection probability must be greater than 0 to select parents.")
-                return
-
-            # Make sure the population is sorted by fitness
-            ga.population.sort_by_best_fitness(ga)
-
             # Choose the tournament size.
             # Use no less than 5 chromosomes per tournament.
             tournament_size = int(len(ga.population)*ga.tournament_size_ratio)
@@ -49,6 +68,9 @@ class Parent_Selection:
 
     class Fitness:
 
+        @Parent_Selection._Parent_Selection__check_selection_probability
+        @Parent_Selection._Parent_Selection__check_positive_fitness
+        @Parent_Selection._Parent_Selection__ensure_sorted
         def roulette(ga):
             """Roulette selection works based off of how strong the fitness is of the
             chromosomes in the population. The stronger the fitness the higher the probability
@@ -58,20 +80,6 @@ class Parent_Selection:
             the ball falls is a randomly generated number between 0 and 1.
             """
 
-            # Make sure the population is sorted by fitness
-            ga.population.sort_by_best_fitness(ga)
-
-            # Error if can't select parents
-            if ga.selection_probability <= 0:
-                print("Selection probability must be greater than 0 to select parents.")
-                return
-
-            # Error if not all chromosomes has positive fitness
-            if (ga.get_chromosome_fitness(0) == 0 or ga.get_chromosome_fitness(-1) < 0):
-                print("Error using roulette selection, all fitnesses must be positive.")
-                print("Consider using stockastic roulette selection or tournament selection.")
-                return
-
             # The sum of all the fitnessess in a population
             fitness_sum = sum(ga.get_chromosome_fitness(index) for index in range(len(ga.population)))
 
@@ -97,6 +105,9 @@ class Parent_Selection:
                         break
 
 
+        @Parent_Selection._Parent_Selection__check_selection_probability
+        @Parent_Selection._Parent_Selection__check_positive_fitness
+        @Parent_Selection._Parent_Selection__ensure_sorted
         def stochastic(ga):
             """Stochastic roulette selection works based off of how strong the fitness is of the
             chromosomes in the population. The stronger the fitness the higher the probability
@@ -104,22 +115,8 @@ class Parent_Selection:
             and incrementally increasing the chance something is selected, the stochastic method
             just divides by the highest fitness and selects randomly."""
 
-            # Make sure the population is sorted by fitness
-            ga.population.sort_by_best_fitness(ga)
-
-            # Error if can't select parents
-            if ga.selection_probability <= 0 or ga.selection_probability >= 1:
-                print("Selection probability must be between 0 and 1 to select parents.")
-                return
-
             max_fitness = ga.get_chromosome_fitness(0)
 
-            # Error if the highest fitness is not positive
-            if max_fitness <= 0:
-                print("Error using stochastic roulette selection, best fitness must be positive.")
-                print("Consider using tournament selection.")
-                return
-
             # Loops until it reaches a desired mating pool size
             while (len(ga.population.get_mating_pool()) < len(ga.population)*ga.parent_ratio):