laglangre.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,
 *2004,9,19
 */
import java.awt.*;
import java.awt.event.*;

public class LagLangre extends Frame  implements MouseListener,ActionListener{
	static LagLangre frm=new LagLangre();
	static Button b1;
	static int array[][]=new int[30][2];
	static int X=0;
	static int count=0;
	static double p=0;	
	public static void main(String[] args){
		frm.setTitle("拉格朗日逼近法");
		b1=new Button("start");
		frm.add(b1,"South");
		frm.setSize(500,500);
 		frm.setLocation(200,200);
		frm.setVisible(true);
		frm.addMouseListener(frm);
		b1.addActionListener(frm);
 		frm.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){System.exit(0);}
		});
	}

		public void mouseEntered(MouseEvent e){	}
		public void mousePressed(MouseEvent e){	}
		public void mouseExited(MouseEvent e){	}
		public void mouseReleased(MouseEvent e){	}

	/*this mouseevent is to get the basic spots
	 */
	 					
		public void mouseClicked(MouseEvent e){
			Graphics g=getGraphics();
			int x=e.getX();
			int y=e.getY();
			array[count][0]=x;array[count][1]=y;
			g.drawString("。",x,y);
			count++;
		}
	
	/*this actionevent is to draw the line
	 */
	  
		public void actionPerformed(ActionEvent e){
			Graphics g=getGraphics();
			for(X=array[0][0];X<array[count-1][0];X++){
				for(long h=0;h<5000000;h++);
				double s=0;
  				for(int i=0;i<count;i++){
					p=(double)array[i][1];
					for(int j=0;j<count;j++){
						if(j!=i)  p=p*(((double)X-(double)array[j][0])/((double)array[i][0]-(double)array[j][0]));
					}
					s=s+p;
				}
			g.drawString(".",X,(int)s);
		}
	}
}