Fix issue where Mutation was duplicating chromosones

README.md

@@ -1,2 +1,7 @@
 # genetic-algorithm
 A simple framework for building and solving genetic algorithms
+
+## Examples
+
+There is an example Travelling Salesman Problem in the `examples/` directory.
+Use `php examples/tsp.php` to watch it in action

src/Population.php

@@ -85,7 +85,8 @@ private function mutate(Organism $a): Organism
         $splicePointA = mt_rand(0, count($dna) - 1);
         $splicePointB = mt_rand(0, count($dna) - 1);
 
-        $dna[$splicePointA] = $dna[$splicePointB];
+        $dna[$splicePointA] = $a->getDna()[$splicePointB];
+        $dna[$splicePointB] = $a->getDna()[$splicePointA];
 
         return $this->parameters->getOrganismFactory()->createFromDna($dna);
     }