布谷鸟算法Java实现源码

package evg.algorithm; import java.util.AbstractMap; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; public class Population { private Map<List<Integer>, Double> nests = new HashMap<List<Integer>,Double>(); private List<Integer> template; private Set<List<Integer>> cacheNests; private Task task; private int numOfNests; private float E; //构造函数 public Population(Task task, int numOfVariables, int numOfNests, float E) { this.task = task; this.template = new ArrayList<Integer>(numOfVariables); for (int i = 0; i < numOfVariables; i++) { this.template.add(i); } this.numOfNests = numOfNests; this.E = E; cacheNests = new HashSet<List<Integer>>(); } public Map<List<Integer>, Double> getNests() { return nests; } //return best Nest in population public Map.Entry<List<Integer>, Double> generate() { int numNests = numOfNests - nests.size();//有疑问？？？ return generateSequence(numNests); } private Map.Entry<List<Integer>, Double> generateSequence(int n) { Double target; Map.Entry<List<Integer>, Double> best = getBestNest(); List<Integer> bestNest = best.getKey(); Double min = best.getValue(); for (int i = 0; i < n; i++) { List<Integer> nest = new ArrayList<Integer>(template); do { Collections.shuffle(nest); } while (!cacheNests.add(nest)); target = task.targetFunction(nest); nests.put(nest, target); if (min == null || target < min) { min = target; bestNest = nest; } } return new AbstractMap.SimpleEntry<List<Integer>,Double>(bestNest, min); } public Map.Entry<List<Integer>, Double> getBestNest() { List<Integer> bestNest = null; Double min = null; for (Map.Entry<List<Integer>, Double> entry : nests.entrySet()) { List<Integer> nest = entry.getKey(); Double target = task.targetFunction(nest);//有疑问 if (min == null || target < min) { min = target; bestNest = nest; } } return new AbstractMap.SimpleEntry<List<Integer>,Double>(bestNest, min); } public void naturalSelection() { arrangeNests(); removeWorstNests(); } public Map<List<Integer>, Double> arrangeNests() { List<Map.Entry<List<Integer>, Double>> sortedList = new ArrayList<Map.Entry<List<Integer>,Double>>(nests.entrySet()); Collections.sort(sortedList,new Comparator<Map.Entry<List<Integer>, Double>>() { @Override public int compare(Map.Entry<List<Integer>, Double> entry1, Map.Entry<List<Integer>, Double> entry2) { return entry1.getValue().compareTo(entry2.getValue()); } }); nests = new HashMap<List<Integer>,Double>(); for (int i = 0; i < sortedList.size(); i++) { Map.Entry<List<Integer>, Double> entry = sortedList.get(i); nests.put(entry.getKey(), entry.getValue()); } return nests; } public void removeWorstNests() { int count = Math.round(nests.size() * E); List<List<Integer>> removedNests = new ArrayList<List<Integer>>(); int i = 0; for (Map.Entry<List<Integer>, Double> entry : nests.entrySet()) { if (nests.size() - count < i) { removedNests.add(entry.getKey()); i++; } for (List<Integer> removedNest : removedNests) { nests.remove(removedNest); } } } }