java - Ant Colony Optimization trouble -
i have problem: build tower formed n colored cubes given side. there can't cube small side on cube bigger side , neither can't 2 neighbor cubes same color. i'm trying solve using ant colony optimization. trouble have don't know how choose next cube move ant on , leave pheromone on it.
example: following cubes: c1 - side = 5, color = red c2 - side = 2, color = green c3 - side = 10, color = blue c4 - side = 1, color = red solution be: c3, c1, c2, c4 i've done far: ant class:
public class ant { private int[] visited; private int size; public ant(int size) { this.size = size; this.visited = new int[size]; } public void clearvisited(){ for(int i=0; < size; i++){ visited[i] = -1; } } public void visit(int index, int cube) { visited[index] = cube; } public int visited(int index){ return visited[index]; } public boolean contains(int cube){ for(int i=0; < size; i++){ if(visited[i] == cube){ return true; } } return false; } } cube class:
public class cube { private int length; private string color; public cube(int length, string color){ this.length = length; this.color = color; } public cube(string color){ this.length = (int)math.round(math.random() * 200); this.color = color; } public int getlength(){ return this.length; } public string getcolor(){ return this.color; } public void setlength(int length){ this.length = length; } public void setcolor(string color){ this.color = color; } public string tostring(){ string str = ""; str += "cub: l = " + length + ", " + "c = " + color; return str; } public boolean equals(object o){ if(o == null){ return false; } if(!(o instanceof cube)){ return false; } cube c = (cube)o; if((c.getcolor().equals(this.getcolor())) && (c.getlength() == this.getlength())){ return true; } return false; } } cube repository class: here store cubes
public class cuberepository { private static arraylist<cube> availablecubes = new arraylist<cube>(); public static void addcube(cube cube){ if(!availablecubes.contains(cube)){ availablecubes.add(cube); } } public static cube getcube(int index){ return availablecubes.get(index); } public static int getsize(){ return availablecubes.size(); } } the aco algorithm:
public class aco { private int nrants; private int nrcubes; private ant[] ants; private int currentindex; private double[] pheromonetrail; private double ph = 1; //pheromon trace on every cube @ start private int alpha = 1; private int beta = 5; private int q = 500; private double q0 = 0.01; public aco(int nrants, int nrcubes){ this.nrants = nrants; this.nrcubes = nrcubes; ants = new ant[nrants]; pheromonetrail = new double[nrcubes]; } public void createants(){//creeaza toate furnicile currentindex = 0; for(int i=0; < nrants; i++){ ants[i] = new ant(nrcubes); } } public ant getant(int index){//return ant return ants[index]; } public void setuppheromonetrail(){ //sets pheromone trail every cube @ start for(int i=0; < nrcubes; i++){ pheromonetrail[i] = ph; } } public void placeants(){ //place every ant on cube for(int i=0; < nrants; i++){ ants[i].visit(currentindex, (int)(math.random() * nrcubes)); } currentindex++; } public int selectnextcube(ant ant){ if(math.random() < q0){ int cube = (int)(math.random() * nrcubes); //pick random cube while(!ant.contains(cube)){ if(cuberepository.getcube(ant.visited(currentindex-1)).getcolor().equals(cuberepository.getcube(cube).getcolor())){ cube = (int)(math.random() * nrcubes); } } return cube; } return 1; //i didn't return proper value } public void moveants(){ //move every ant on cube while(currentindex < nrcubes){ for(int i=0; < nrants; i++){ ants[i].visit(currentindex, selectnextcube(ants[i])); } currentindex++; } } }
without having understood whole program (it's far read , find answer): may select random cube has different color previous 1 pseudocode this
private static final random random = new random(0); public int selectnextcube(ant ant) { cube previouscube = cuberepository.getcube(ant.visited(currentindex-1)); list<cube> allcubes = obtainallcubesfromcuberepository(); list<cube> samecolor = obtainallcubeswithsamecoloras(previouscube); allcubes.removeall(samecolor); // edit>>>: might need this: allcubes.remove(computeallcubesalreadyvisitedby(ant)); // <<<edit: might need this: int index = random.nextint(allcubes.size()); cube nextcube = allcubes.get(index); return indexfor(nextcube); } btw: i'd strongly recomment not use math.random(). returns unpredictable random value. debugging program involves math.random() horrible. instead, should use instance of java.lang.random, shown in above snippet. may call random.nextdouble() in order obtain double values math.random(). additionally, may call random.nextint(n) obtain int values in range [0,n). important thing is: when create instance new random(0) return same sequence of random numbers. makes program predictable , makes possible debug program. (if want "unpredictable" random number sequence, can instantiate new random(), without random seed).
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