Java学习丛书科学与工程数值算法（Java版）一书的代码

				 import java.applet.*;
				 import java.awt.*;
				 public class Example2_9 extends Applet
				{  public static boolean LU(double[][] a,int n)
				  { int i,j,k;
				    if (a[0][0]==0)return false;
				    for(i=1;i				    for(i=1;i				    { for(k=0;k				      if(a[k][k]==0)return false;
					  for(j=i+1;j					    { for(k=0;k					      for(k=0;k					      a[j][i]/=a[i][i];
					    }
					}
				      return true;
				  }
				
				  public void paint(Graphics g)
				  {double[][] a={{2,4,4,2},{3,3,12,6},{2,4,-1,2},{4,2,1,1}};
				   double[][] l=new double[4][4];
				   int i,j;
				   if(LU(a,4))
				   {for(i=0;i				      {for(j=0;j				        l[i][i]=1;}
				    g.drawString("下三角L为：",10,20);
				    g.drawString(""+l[0][0]+"  "+l[0][1]+"  "+l[0][2]+"  "+l[0][3],10,40);
					g.drawString(""+l[1][0]+"  "+l[1][1]+"  "+l[1][2]+"  "+l[1][3],10,60);
					g.drawString(""+l[2][0]+"  "+l[2][1]+"  "+l[2][2]+"  "+l[2][3],10,80);
				    g.drawString(""+l[3][0]+"  "+l[3][1]+"  "+l[3][2]+"  "+l[3][3],10,100);
				    g.drawString("上三角U为:",10,120);
					g.drawString(""+a[0][0]+"  "+a[0][1]+"  "+a[0][2]+"  "+a[0][3],10,140);
				    g.drawString(""+a[1][0]+"  "+a[1][1]+"  "+a[1][2]+"  "+a[1][3],10,160);
				    g.drawString(""+a[2][0]+"  "+a[2][1]+"  "+a[2][2]+"  "+a[2][3],10,180);
				    g.drawString(""+a[3][0]+"  "+a[3][1]+"  "+a[3][2]+"  "+a[3][3],10,200);}
				    else g.drawString("矩阵无法分解",10,20);
				  }
				
				}