ch3_3_1.java

Java环境下实现的数值分析程序

class ch3_3_1{
	static void GaiJin(double[][] A,int m,int n){
		double [][]L=new double[m][n];
		double[]x=new double[m]; 
		for(int i=0;i<n;i++){
			L[0][i]=A[0][i];
		}
		for(int i=1;i<m;i++){
			L[i][0]=L[0][i]/L[0][0];
		}
		for(int i=1;i<m;i++){
			for(int j=i;j<n;j++){
				L[i][j]=A[i][j];
				for(int k=0;k<i;k++){
					L[i][j]-=L[i][k]*L[k][j];
				}
			}
			for(int a=i+1;a<m;a++){
				L[a][i]=L[i][a]/L[i][i];
			}
		}
		x[m-1]=L[m-1][n-1]/L[m-1][n-2];
		for(int i=m-2;i>=0;i--){
			x[i]=L[i][n-1];
			for(int j=n-2;j>i;j--){
				x[i]-=L[i][j]*x[j];
			}
			x[i]=x[i]/L[i][i];
		}
		for(int i=0;i<m;i++){
			System.out.println("x["+(i+1)+"]="+x[i]);
		}
	}
	public static void main(String [] args){
		int m=6;
		int n=7;
		double [][] a={{0.5,-0.5,0.0,0.0,0.0,0.0,-1.0},{-0.5,1.5,-0.5,-0.25,0.25,0.0,0.0},{0.0,-0.5,1.5,0.25,-0.25,0.0,0.0},{0.0,-0.25,0.25,1.5,-0.5,0.0,0.0},{0.0,0.25,-0.25,-0.5,1.5,-0.5,0.0},{0.0,0.0,0.0,0.0,-0.5,0.5,0.0}};
		GaiJin(a,m,n);
	}
}