Ensure sorted not needed.

The problem was not appending old chromosomes to the front of the next population during survivor selection.

src/mutation/mutation_methods.py

@@ -35,17 +35,6 @@ def check_gene_mutation_rate(individual_method):
     return new_method
 
 
-def ensure_sorted(population_method):
-    """Sorts the population by fitness before running."""
-
-    def new_method(ga):
-
-        ga.population.sort_by_best_fitness(ga)
-        population_method(ga)
-
-    return new_method
-
-
 def loop_selections(population_method):
     """Runs the population method until enough chromosomes are mutated."""
 
@@ -78,7 +67,6 @@ class Mutation_Methods:
     # Private method decorators, see above.
     _check_chromosome_mutation_rate = check_chromosome_mutation_rate
     _check_gene_mutation_rate       = check_gene_mutation_rate
-    _ensure_sorted   = ensure_sorted
     _loop_selections = loop_selections
     _loop_mutations  = loop_mutations
 
@@ -96,7 +84,6 @@ class Mutation_Methods:
 
 
         @check_chromosome_mutation_rate
-        @ensure_sorted
         @loop_selections
         def random_avoid_best(ga):
             """Selects random chromosomes while avoiding the best chromosomes. (Elitism)"""