randomconstant.java

这是用遗传编程算法来拟合曲线的一个经典程序

/*作者：徐朝*/
/*[e-mail]*/
package regression.function;
import java.util.*;
import kernel.*;
/**
*随机数类，继承了Terminal类，返回一个随机数对象
*/
public class RandomConstant extends Terminal 
{
	
	double value;
	//定义最小值和最大值
	static final double MIN = -4.0;
	static final double MAX = +4.0;
    //构造函数，对value进行求值，构造一个在-5到+5之间的值,其中GP类是后面会定义的基类
	public RandomConstant() {
		Random r = Kernel.random;
		value = r.nextDouble() * (MAX - MIN) + MIN;
		symbol = value + "";
	}

	private RandomConstant(double value) {
		this.value = value;
		this.symbol = value + "";
	}

	public Object DeepClone() 
	{
		return new RandomConstant(this.value); 
	}

	public Object eval() {
		return new Double(value);
	}

}