halfsearch.java

数值算法例子,牛顿插值,拉格朗日,三次样条

/*@author 邱宇峰 ,software project031
 *2004,10,6
 */
import java.math.*;
import java.awt.*;
import java.awt.event.*;

public class halfSearch extends Frame implements ActionListener{
	static halfSearch frm=new halfSearch();
	static Button b1;
	static int array[][]=new int[30][2];
	static int X=0;
	static int x=0;
	static int count=0;
	static double p=0;	
	public static void main(String[] args){
		frm.setTitle("二分搜索求sin函数");
		b1=new Button("click to start");
		frm.add(b1,"South");
		frm.setSize(500,500);
 		frm.setLocation(200,200);
		frm.setVisible(true);
		b1.addActionListener(frm);
 		frm.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){System.exit(0);}
		});
	}
	
	public void paint(Graphics g){
		double X,Y;
		g.drawLine(50,300,450,300);
		g.drawLine(250,150,250,300);
		g.drawString("0",250,310);
		g.drawString("1.57",407,310);
		g.drawString("-1.57",73,310);	
		for(X=-2;X<=2;X+=0.01){
			Y=100*Math.sin(X);
			g.drawString(".",50+x,300-(int)Y);
			x++;
		}	
	}

	/*this actionevent is to draw the line
	 */
	  
		public void actionPerformed(ActionEvent h){
			Graphics g=getGraphics();
			double a=-2,b=2,e=0.00001,X;
			while(b-a>e){
				X=(a+b)/2;
					if((a-2*Math.sin(a))*(X-2*Math.sin(X))<0) b=X;
					else a=X;
					g.setColor(Color.blue);
					g.drawLine(250+(int)(100*a),300,250+(int)(100*a),300-(int)(100*Math.sin(a)));
					g.drawLine(250-(int)(100*a),300,250-(int)(100*a),300+(int)(100*Math.sin(a)));
					g.setColor(Color.yellow);
					g.drawLine(250+(int)(100*b),300,250+(int)(100*b),300-(int)(100*Math.sin(b)));
					g.drawLine(250-(int)(100*b),300,250-(int)(100*b),300+(int)(100*Math.sin(b)));	
					if(Math.abs(X-2*Math.sin(X))<0.00001){
						g.setColor(Color.red);
						g.drawString("。",250+(int)(100*X),300-(int)(100*Math.sin(X)));
						g.drawString("。",250-(int)(100*X),300+(int)(100*Math.sin(X)));
					}
					for(int i=0;i<50000000;i++);
					g.setColor(Color.white);
					g.drawLine(250+(int)(100*a),300,250+(int)(100*a),300-(int)(100*Math.sin(a)));
					g.drawLine(250-(int)(100*a),300,250-(int)(100*a),300+(int)(100*Math.sin(a)));
					g.drawLine(250+(int)(100*b),300,250+(int)(100*b),300-(int)(100*Math.sin(b)));
					g.drawLine(250-(int)(100*b),300,250-(int)(100*b),300+(int)(100*Math.sin(b)));
			}
		}				
	}




 /*
 
class carrySearch{
	double a=-1,b=1,e=0.0001,X1,X2,f1,f2;
	double Search(){
		X1=a+0.382*(b-a);
		X2=a+0.618*(b-a);
		f1=Math.cos(X1);
		f2=Math.cos(X2);
		while(b-a>e){
			if(f2>f1){
				a=X1;X1=X2;f1=f2;X2=a+0.618*(b-a);f2=Math.cos(X2);
			}
			else{
				b=X2;X2=X1;f2=f1;X1=a+0.382*(b-a);f1=Math.cos(X1);
			}
		}
		X1=(a+b)/2;
		//System.out.println("Y "+f1);
		return(X1);
	}
}
 */