doc/classes/Population.src/.svn/text-base/M000019.html.svn-base

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   8   <title>crossover (Population)</title>
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  13   <pre><span class="ruby-comment cmt"># File lib/libgenetics.rb, line 141</span>
  14   <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">crossover</span>(<span class="ruby-identifier">crossover_rate</span>)
  15     <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>
  16     <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>)
  17     <span class="ruby-keyword kw">while</span> <span class="ruby-identifier">parents</span>.<span class="ruby-identifier">length</span> <span class="ruby-operator">&gt;</span> <span class="ruby-value">1</span>
  18       <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>))
  19       <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>))
  20       <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">rand</span> <span class="ruby-operator">&lt;</span> <span class="ruby-identifier">crossover_rate</span>
  21         <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>)
  22         <span class="ruby-identifier">next_population</span>.<span class="ruby-identifier">individuals</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">child1</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">child2</span>
  23       <span class="ruby-keyword kw">else</span>
  24         <span class="ruby-identifier">next_population</span>.<span class="ruby-identifier">individuals</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">parent1</span> <span class="ruby-operator">&lt;&lt;</span> <span class="ruby-identifier">parent2</span>
  25       <span class="ruby-keyword kw">end</span>
  26     <span class="ruby-keyword kw">end</span>
  27     <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>
  28     <span class="ruby-identifier">next_population</span>
  29   <span class="ruby-keyword kw">end</span></pre>
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