Fix building and installing package.

[genetic.git] / include / selection / linearRankSelection.h

diff --git a/include/selection/linearRankSelection.h b/include/selection/linearRankSelection.h
new file mode 100644 (file)
index 0000000..8bbd3ce
--- /dev/null
+++ b/include/selection/linearRankSelection.h
@@ -0,0 +1,122 @@
+#ifndef __SELECTION_LINEAR_RANK_H
+#define __SELECTION_LINEAR_RANK_H
+
+#include <map>
+
+#include "chromosome.h"
+#include "generation.h"
+#include "fitness/fitness.h"
+#include "selection/selection.h"
+
+using namespace std;
+
+namespace genetic {
+//     namespace selection {
+        /**
+         * Linear Rank Selection class.
+         * Based on the 
+         */
+        template < typename _Chromosome >
+        class LinearRankSelection : public Selection<_Chromosome> {
+        public:
+            /**
+             * Type representing Fitness function
+             */
+            typedef Fitness<_Chromosome> GeneticFitness;
+
+            /**
+             * Value type returned by the Fitness function
+             */
+            typedef typename GeneticFitness::ValueType FitnessValueType;
+        protected:
+            /**
+             * Type representing mapped Chromosome by its Rank value
+             */
+            typedef typename std::multimap<FitnessValueType, _Chromosome> ChromosomeMap;
+
+            /** Iterator for ChromosomeMap */
+            typedef typename ChromosomeMap::iterator ChromosomeMapIterator;
+
+            /**
+             * Calculates Ranks for the Chromosomes
+             *
+             * @return multimap containing ranked Chromosomes, where key is the
+             *      rank value.
+             */
+            ChromosomeMap rankChromosomes() {
+                const unsigned int generationSize = this->generation.size();
+                FitnessValueType fitness = 0;
+
+                ChromosomeMap generationFitness;
+
+                for (unsigned int i = 0; i < generationSize; i++) {
+                    fitness = this->checkChromosomeFitness(this->generation[i]);
+                    generationFitness.insert(std::make_pair(fitness, this->generation[i]));
+                }
+
+                // multimap is automatically sorted by key, so we don't need to
+                // sort it again
+
+                // p(i) = (rank(i) / N*(N-1)), where rankedGeneration[i] = p(i)
+                ChromosomeMap rankedGeneration;
+
+                unsigned int rank = generationSize;
+                double denominator = generationSize * (generationSize - 1);
+
+                for (ChromosomeMapIterator it = generationFitness.begin(); it != generationFitness.end(); it++) {
+                    rankedGeneration.insert(std::make_pair(rank--/denominator, it->second));
+                }
+
+                return rankedGeneration;
+            }
+
+            /**
+             * Invokes Selection calculations of the Linear Rank Selection
+             *
+             * @return new Generation of Chromosome's that passed the Selection
+             */
+            virtual Generation<_Chromosome> do_draw() {
+                ChromosomeMap probabilities = rankChromosomes();
+
+                unsigned int size = probabilities.size();
+                unsigned int denominator = size * (size - 1);
+
+                std::vector<_Chromosome> selected;
+
+                /** Random value used to draw chromosome */
+                FitnessValueType random = 0;
+
+                while (size > 0) {
+                    bool found = false;
+                    random = (rand() % size) / (double)denominator;
+
+                    for (ChromosomeMapIterator it = probabilities.begin(); it != probabilities.end(); it++) {
+                        if (random < it->first) {
+                            found = true;
+                            selected.push_back(it->second);
+                            break;
+                        }
+                        // When NaN occur, just get first Chromosome
+                        else if (it->first != it->first) {
+                            selected.push_back(probabilities.begin()->second);
+                            found = true;
+                            break;
+                        }
+                    }
+
+                    if (found) {
+                        size--;
+                    }
+                }
+
+                return Generation<_Chromosome>(selected);
+            }
+        public:
+            LinearRankSelection(Generation<_Chromosome> _generation, GeneticFitness& _fitness) :
+                Selection<_Chromosome>(_generation, _fitness) {
+            }
+        };
+//     }
+}
+
+#endif /* __SELECTION_LINEAR_RANK_H */