gaainversion.java

来自「Java实现的遗传算法工具集：GA Playground」· Java 代码 · 共 86 行

public class GaaInversion {
	
	int gaType;
	int inversionType;
	double inversionRate;
	
	public GaaInversion (GaaProblem problem) {
		
		gaType = problem.gaType;
		inversionType = problem.inversionType;
		inversionRate = problem.inversionRate;
		
	}


	public String inversion(String chrom) {
		
		String s = doInversion(chrom, inversionRate);
		return(s);
		
	}


	public String inversion(String chrom, double rate) {
		
		String s = doInversion(chrom, rate);
		return(s);
		
	}

	public String doInversion(String chrom, double rate) {
		
		int i, pos1, pos2, temp;
		String s1, s2, s3, s="";
		
		if (GaaMisc.flip(rate)) {
			pos1 =(int) Math.floor((Math.random()*(chrom.length()-1)));
			pos2 =(int) Math.floor((Math.random()*(chrom.length()-1)));
			if (pos1 > pos2) {
				temp = pos2;
				pos2 = pos1;
				pos1 = temp;
			}
			if ((pos2-pos1) > 1) {
				try{
				s1 = chrom.substring(0,pos1);
				s2 = chrom.substring(pos1,pos2);
				s3 = chrom.substring(pos2);
				s2 = invertString(s2);
				s = s1.concat(s2);
				s = s.concat(s3);
				}
				catch (Exception e) {
					GaaAction.deb.debug("GaaInversion Inversion error: "+e.toString());	
				}
			}
			else
				s = chrom;
		}
		else
			s = chrom;

		return s;

	}		
	
	
	String invertString(String txt) {
		
			int i, size;
			
			size = txt.length();
			StringBuffer sbfrom = new StringBuffer(txt);
			StringBuffer sbto = new StringBuffer(txt);
			
			for (i=0;i<size;i++) {
				sbto.setCharAt(i,sbfrom.charAt(size-i-1));
			}
				
			return(sbto.toString());
			
	}

	
}