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<title>crossover (Population)</title>
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<pre><span class="ruby-comment cmt"># File lib/libgenetics.rb, line 138</span>
<span class="ruby-keyword kw">def</span> <span class="ruby-identifier">crossover</span>(<span class="ruby-identifier">crossover_rate</span>)
<span class="ruby-identifier">parents</span> = <span class="ruby-ivar">@individuals</span>.<span class="ruby-identifier">dup</span> <span class="ruby-comment cmt"># genomes that haven't been parents yet</span>
<span class="ruby-identifier">next_population</span> = <span class="ruby-constant">Population</span>.<span class="ruby-identifier">new</span>(<span class="ruby-value">0</span>)
<span class="ruby-keyword kw">while</span> <span class="ruby-identifier">parents</span>.<span class="ruby-identifier">length</span> <span class="ruby-operator">></span> <span class="ruby-value">1</span>
<span class="ruby-identifier">parent1</span> = <span class="ruby-identifier">parents</span>.<span class="ruby-identifier">delete_at</span>(<span class="ruby-identifier">rand</span>(<span class="ruby-identifier">parents</span>.<span class="ruby-identifier">length</span>))
<span class="ruby-identifier">parent2</span> = <span class="ruby-identifier">parents</span>.<span class="ruby-identifier">delete_at</span>(<span class="ruby-identifier">rand</span>(<span class="ruby-identifier">parents</span>.<span class="ruby-identifier">length</span>))
<span class="ruby-keyword kw">if</span> <span class="ruby-identifier">rand</span> <span class="ruby-operator"><</span> <span class="ruby-identifier">crossover_rate</span>
<span class="ruby-identifier">child1</span>, <span class="ruby-identifier">child2</span> = <span class="ruby-identifier">parent1</span>.<span class="ruby-identifier">crossover</span> <span class="ruby-identifier">parent2</span>, <span class="ruby-identifier">rand</span>(<span class="ruby-identifier">parent1</span>.<span class="ruby-identifier">genome</span>.<span class="ruby-identifier">length</span>)
<span class="ruby-identifier">next_population</span>.<span class="ruby-identifier">individuals</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">child1</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">child2</span>
<span class="ruby-keyword kw">else</span>
<span class="ruby-identifier">next_population</span>.<span class="ruby-identifier">individuals</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">parent1</span> <span class="ruby-operator"><<</span> <span class="ruby-identifier">parent2</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-keyword kw">end</span>
<span class="ruby-identifier">next_population</span> <span class="ruby-operator">+=</span> <span class="ruby-identifier">parents</span> <span class="ruby-comment cmt"># pick up any parents that didn't get a chance to mate</span>
<span class="ruby-identifier">next_population</span>
<span class="ruby-keyword kw">end</span></pre>
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