Simple selection strategy

Author: petercoles

src/Population.php

@@ -36,6 +36,11 @@ public function findBest()
         return $s->where('fitness', $s->max('fitness'))->first();
     }
 
+    public function select($number)
+    {
+        return collect($this->solutions)->sortByDesc('fitness')->take($number);
+    }
+
     protected function initialise()
     {
         for ($i = 0; $i < $this->size; $i++) {

tests/PopulationTest.php

@@ -51,4 +51,13 @@ public function can_evaluate_a_population_with_evaluation_data()
         $this->assertEquals([64, -39, 1], $best->chromosomes(), '', 0.0001);
         $this->assertEquals(758, $best->fitness(), '', 0.0001);
     }
+
+    /** @test */
+    public function apply_selection_strategy()
+    {
+        $population = new Population(Integers::class, 12);
+        $selections = $population->select(6);
+
+        $this->assertCount(6, $selections);
+    }
 }