eo/src/eoRandomSelect.h

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+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+//-----------------------------------------------------------------------------
+// eoRandomSelect.h
+// (c) GeNeura Team, 1998
+//-----------------------------------------------------------------------------
+
+#ifndef EORANDOMSELECT_H
+#define EORANDOMSELECT_H
+
+//-----------------------------------------------------------------------------
+
+#include <algorithm>
+#include <numeric>    // for accumulate
+#include <functional>
+
+#include <eoPopOps.h>
+#include <eoUniform.h>
+
+//-----------------------------------------------------------------------------
+
+/** 
+ * eoRandomSelect: an selection operator, which selects randomly a percentage
+ of the initial population.
+ */
+template<class EOT> class eoRandomSelect: public eoSelect<EOT>
+{
+ public:
+  ///
+  eoRandomSelect(const float& _percent = 0.4): eoSelect<EOT>(), rate(_percent) {};
+  
+  ///
+  virtual ~eoRandomSelect() {};
+  
+  /// Takes a percentage of the population randomly, and transfers it to siblings
+  virtual void operator() ( const eoPop<EOT>& _parents, eoPop<EOT>& _siblings ) const {
+    // generates random numbers
+    eoUniform<unsigned> uniform(0, _parents.size()-1);
+    unsigned num_chroms = (unsigned)(rate * _parents.size());
+
+    // selection of chromosomes
+    do {
+      _siblings.push_back(_parents[uniform()]);
+    } while (_siblings.size() < num_chroms);
+  }
+
+    /// @name Methods from eoObject
+  //@{
+  /**
+   * Read object. Reads the percentage
+   * Should call base class, just in case.
+   * @param _s A istream.
+   */
+  virtual void readFrom(istream& _s) {
+	_s >> rate;
+  }
+
+  /** Print itself: inherited from eoObject implementation. Declared virtual so that 
+      it can be reimplemented anywhere. Instance from base classes are processed in
+	  base classes, so you don´t have to worry about, for instance, fitness.
+  @param _s the ostream in which things are written*/
+  virtual void printOn( ostream& _s ) const{
+	_s << rate;
+  }
+
+  /** Inherited from eoObject 
+      @see eoObject
+  */
+  string className() const {return "eoRandomSelect";};
+
+  //@}
+
+
+ private:
+  float rate;
+};
+
+//-----------------------------------------------------------------------------
+
+#endif EOGSRANDOMSELECT_H