org.evosuite.ga.Neighbourhood Maven / Gradle / Ivy
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package org.evosuite.ga;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import org.evosuite.Properties;
/**
* Construction of a grid and the neighbourhood models
*
* @author Nasser Albunian
*/
public class Neighbourhood implements NeighborModels,Serializable{
private static final long serialVersionUID = 1L;
/** The population size **/
private int population_size;
/** Position values of different neighbourhood based on the direction **/
private int _L, _R, _N, _S, _W, _E, _NE, _NW, _SE, _SW, _NN, _SS, _EE, _WW;
/** An array that represents the grid **/
int neighbour[][];
/** Number of chromosomes per one row of a grid **/
int columns;
/**
* Collection of cells will be returned by different models of neighbourhood
*/
private List chromosomes = new ArrayList<>();
public Neighbourhood (int populationSize){
population_size = populationSize;
neighbour = new int[population_size][0];
columns = (int)Math.sqrt(population_size);
constructNeighbour();
}
/**
* Construct the grid and define positions of neighbours for each individual
*/
public void constructNeighbour(){
for(int i=0; i columns - 1)
{
neighbour[i][Positions.N.ordinal()] = i - columns;
}
else
{
int mod = population_size % columns;
if(mod != 0){
int thisPosition = ((i - columns + population_size) % population_size);
if(i == 0){
neighbour[i][Positions.N.ordinal()] = population_size - (mod);
}else{
if(mod > 1){
if(i >= mod){
neighbour[i][Positions.N.ordinal()] = thisPosition - mod;
}else{
neighbour[i][Positions.N.ordinal()] = thisPosition + 1;
}
}else{
neighbour[i][Positions.N.ordinal()] = thisPosition - 1;
}
}
}else{
neighbour[i][Positions.N.ordinal()] = (i - columns + population_size) % population_size;
}
}
//~~~~ SOUTH ~~~~//
int thisPosition = (i + columns) % population_size;
if(population_size % columns != 0 && i+columns>=population_size){
neighbour[i][Positions.S.ordinal()] = i % columns;
}else{
neighbour[i][Positions.S.ordinal()] = thisPosition;
}
//~~~~ EAST ~~~~//
if ((i + 1) % columns == 0)
{
neighbour[i][Positions.E.ordinal()] = i - (columns - 1);
}
else
{
if(population_size % columns != 0 && i == population_size-1){
neighbour[i][Positions.E.ordinal()] = (i % columns) + 1;
}else{
neighbour[i][Positions.E.ordinal()] = i + 1;
}
}
//~~~~ WEST ~~~~//
if (i % columns == 0)
{
int westPosition = i + (columns - 1);
if(westPosition >= population_size){
neighbour[i][Positions.W.ordinal()] = neighbour[i][Positions.E.ordinal()];
}else{
neighbour[i][Positions.W.ordinal()] = westPosition;
}
}
else
{
neighbour[i][Positions.W.ordinal()] = i - 1;
}
}
//~~~~ NW, SW, NE, SE ~~~~//
for(int i=0; i ringTopology(List collection, int position) {
if (position-1 < 0){
_L = collection.size() - 1;
}else{
_L = position - 1;
}
if (position+1 > collection.size() - 1){
_R = 0;
}else{
_R = position + 1;
}
chromosomes.add((T) collection.get(_L));
chromosomes.add((T) collection.get(position));
chromosomes.add((T) collection.get(_R));
return chromosomes;
}
/**
* Retrieve neighbours of a chromosome according to the linear five model (i.e. L5)
* @param collection The current collection of chromosomes
* @param position The position of a chromosome which its neighbours will be retrieved
* @return collection of neighbours
*/
@SuppressWarnings("unchecked")
public List linearFive(List collection, int position) {
_N = neighbour[position][Positions.N.ordinal()];
_S = neighbour[position][Positions.S.ordinal()];
_E = neighbour[position][Positions.E.ordinal()];
_W = neighbour[position][Positions.W.ordinal()];
chromosomes.add((T) collection.get(_N));
chromosomes.add((T) collection.get(_S));
chromosomes.add((T) collection.get(_E));
chromosomes.add((T) collection.get(_W));
chromosomes.add((T) collection.get(position));
return chromosomes;
}
/**
* Retrieve neighbours of a chromosome according to the compact nine model (i.e. C9)
* @param collection The current collection of chromosomes
* @param position The position of a chromosome which its neighbours will be retrieved
* @return collection of neighbours
*/
@SuppressWarnings("unchecked")
public List compactNine(List collection, int position) {
_N = neighbour[position][Positions.N.ordinal()];
_S = neighbour[position][Positions.S.ordinal()];
_E = neighbour[position][Positions.E.ordinal()];
_W = neighbour[position][Positions.W.ordinal()];
_NW = neighbour[neighbour[position][Positions.N.ordinal()]][Positions.W.ordinal()];
_SW = neighbour[neighbour[position][Positions.S.ordinal()]][Positions.W.ordinal()];
_NE = neighbour[neighbour[position][Positions.N.ordinal()]][Positions.E.ordinal()];
_SE = neighbour[neighbour[position][Positions.S.ordinal()]][Positions.E.ordinal()];
chromosomes.add((T) collection.get(_N));
chromosomes.add((T) collection.get(_S));
chromosomes.add((T) collection.get(_E));
chromosomes.add((T) collection.get(_W));
chromosomes.add((T) collection.get(_NW));
chromosomes.add((T) collection.get(_SW));
chromosomes.add((T) collection.get(_NE));
chromosomes.add((T) collection.get(_SE));
chromosomes.add((T) collection.get(position));
return chromosomes;
}
/**
* Retrieve neighbours of a chromosome according to the linear compact thirteen (i.e. C13)
* @param collection The current collection of chromosomes
* @param position The position of a chromosome which its neighbours will be retrieved
* @return collection of neighbours
*/
@SuppressWarnings("unchecked")
public List CompactThirteen(List collection, int position) {
_N = neighbour[position][Positions.N.ordinal()];
_S = neighbour[position][Positions.S.ordinal()];
_E = neighbour[position][Positions.E.ordinal()];
_W = neighbour[position][Positions.W.ordinal()];
_NW = neighbour[neighbour[position][Positions.N.ordinal()]][Positions.W.ordinal()];
_SW = neighbour[neighbour[position][Positions.S.ordinal()]][Positions.W.ordinal()];
_NE = neighbour[neighbour[position][Positions.N.ordinal()]][Positions.E.ordinal()];
_SE = neighbour[neighbour[position][Positions.S.ordinal()]][Positions.E.ordinal()];
_NN = neighbour[_N][Positions.N.ordinal()];
_SS = neighbour[_S][Positions.S.ordinal()];
_EE = neighbour[_E][Positions.E.ordinal()];
_WW = neighbour[_W][Positions.W.ordinal()];
chromosomes.add((T) collection.get(_N));
chromosomes.add((T) collection.get(_S));
chromosomes.add((T) collection.get(_E));
chromosomes.add((T) collection.get(_W));
chromosomes.add((T) collection.get(_NW));
chromosomes.add((T) collection.get(_SW));
chromosomes.add((T) collection.get(_NE));
chromosomes.add((T) collection.get(_SE));
chromosomes.add((T) collection.get(_NN));
chromosomes.add((T) collection.get(_SS));
chromosomes.add((T) collection.get(_EE));
chromosomes.add((T) collection.get(_WW));
chromosomes.add((T) collection.get(position));
return chromosomes;
}
/**
* Retrieve neighbours of a chromosome
* @param current_pop The current population
* @param chromosome The chromosome which its neighbours will be retrieved
* @return neighbours as a collection
*/
public List getNeighbors(List current_pop, int chromosome){
switch(Properties.MODEL){
case ONE_DIMENSION: return this.ringTopology(current_pop, chromosome);
case LINEAR_FIVE: return this.linearFive(current_pop, chromosome);
case COMPACT_NINE: return this.compactNine(current_pop, chromosome);
case COMPACT_THIRTEEN: return this.CompactThirteen(current_pop, chromosome);
default: return this.linearFive(current_pop, chromosome);
}
}
}
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