eo/src/EO.h

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+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+//-----------------------------------------------------------------------------
+// EO.h
+// (c) GeNeura Team 1998
+//-----------------------------------------------------------------------------
+
+#ifndef EO_H
+#define EO_H
+
+//-----------------------------------------------------------------------------
+
+#include <stdexcept>  // runtime_error 
+
+#include <eoObject.h>
+#include <eoPersistent.h>
+
+//-----------------------------------------------------------------------------
+/** EO is a base class for evolvable objects, that is, the subjects of evolution.
+    EOs have only got a fitness, which at the same time needs to be only an object with the
+    operation less than (<) defined. Fitness says how good is the object; evolution or change
+    of these objects is left to the genetic operators. A fitness less than another means a 
+    worse fitness, in whatever the context; thus, fitness is always maximized; although 
+    it can be minimized with a proper definition of the < operator.\\
+    The fitness object must have, besides an void ctor, a copy ctor.
+*/
+template<class F> class EO: public eoObject, public eoPersistent
+{
+public:
+  typedef F Fitness;
+  
+  /** Default constructor.
+      Fitness must have a ctor which takes 0 as a value; we can not use void ctors here
+      since default types like float have no void initializer. VC++ allows it, but gcc does not
+  */
+  EO(): repFitness(0), invalidFitness(true) {}
+
+  /** Ctor from stream.
+      Fitness must have defined the lecture from an istream.
+  */
+  EO( istream& _is ) {
+    _is >> repFitness;
+    validFitness = true;
+  };
+
+  /// Copy ctor
+  EO( const EO& _eo ): repFitness( _eo.repFitness ), invalidFitness( _eo.invalidFitness ) {};
+  
+  /// Virtual dtor
+  virtual ~EO() {};
+
+  /// Return fitness value.
+  Fitness fitness() const
+    {
+      if (invalid())
+	throw runtime_error("invalid fitness");
+      return repFitness;
+    }
+  
+  // Set fitness as invalid.
+  void invalidate() { invalidFitness = true; }
+  
+  /** Set fitness. At the same time, validates it.
+   *  @param _fitness New fitness value.
+   */
+  void fitness(const Fitness& _fitness)
+    { 
+      repFitness = _fitness;
+      invalidFitness = false;
+    }
+  
+  /** Return true If fitness value is invalid, false otherwise.
+   *  @return true If fitness is invalid.
+   */
+  bool invalid() const { return invalidFitness; }
+  
+  /// Methods inherited from eoObject
+  //@{
+  
+  /** Return the class id. 
+   *  @return the class name as a string
+   */
+  virtual string className() const { return "EO"; };
+  
+  /**
+   * Read object.\\
+   * Calls base class, just in case that one had something to do. The read and print 
+   * methods should be compatible and have the same format. In principle, format is 
+   * "plain": they just print a number
+   * @param _is a istream.
+   * @throw runtime_exception If a valid object can't be read.
+   */
+  virtual void readFrom(istream& _is) {
+    _is >> repFitness;
+    invalidFitness = false;
+  }
+  
+  /**
+   * Write object. It's called printOn since it prints the object _on_ a stream.
+   * @param _os A ostream.
+   */
+  virtual void printOn(ostream& _os) const {
+    _os << repFitness << endl;
+  }
+  
+  //@}
+  
+private:
+  Fitness repFitness;   // value of fitness for this chromosome
+  bool invalidFitness;  // true if the value of fitness is invalid
+};
+
+//-----------------------------------------------------------------------------
+
+template<class T> bool operator<(const EO<T>& eo1, const EO<T>& eo2)
+{
+  return eo1.fitness() < eo2.fitness();
+}
+
+//-----------------------------------------------------------------------------
+
+
+#endif EO_H