Code:
import java.util.Scanner;
public class LUDecomposition
{
public static void main(String args[])
{
System.out.println("Enter the dimension of the matrix:");
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
double [][]mat = new double[n][n];
for(int i=0; i
for(int j=0; j
mat[i][j] = sc.nextDouble();
if(n==2)
{
double [][]l = new double[n][n];
l[0][0] = l[1][1] = 1;
l[0][1] = 0;
double [][]u = new double[n][n];
u[1][0] = 0;
u[0][0] = mat[0][0];
u[0][1] = mat[0][1];
l[1][0] = mat[1][0]/mat[0][0];
u[1][1] = mat[1][1] - (l[1][0]*u[0][1]); //mat[2][2]-(mat[2][1]*mat[1][2]/mat[1][1]);
System.out.println("The L Component is:");
for(int i=0; i
{
for(int j=0; j
System.out.print(" "+l[i][j]);
System.out.println();
}
System.out.println("The U Component is:");
for(int i=0; i
{
for(int j=0; j
System.out.print(" "+u[i][j]);
System.out.println();
}
}
if(n==3)
{
double [][]l = new double[n][n];
l[0][0] = l[1][1] = l[2][2] = 1;
l[0][1] = l[0][2] = l[1][2] = 0;
double [][]u = new double[n][n];
u[1][0] = u[2][0] = u[2][1] = 0;
u[0][0] = mat[0][0];
u[0][1] = mat[0][1];
u[0][2] = mat[0][2];
l[1][0] = mat[1][0]/mat[0][0];
u[1][1] = mat[1][1] - (l[1][0]*u[0][1]); //mat[2][2]-(mat[2][1]*mat[1][2]/mat[1][1]);
u[1][2] = mat[1][2] - (l[1][0]*u[0][2]);
l[2][0] = mat[2][0]/u[0][0];
l[2][1] = (mat[2][1] - l[2][1]*u[0][1])/u[1][1];
u[2][2] = mat[2][2] - (l[2][0]*u[0][2]) - (l[2][1]*u[1][2]);
System.out.println("The L Component is:");
for(int i=0; i
{
for(int j=0; j
System.out.print(" "+l[i][j]);
System.out.println();
}
System.out.println("The U Component is:");
for(int i=0; i
{
for(int j=0; j
System.out.print(" "+u[i][j]);
System.out.println();
}
}
sc.close();
}
}
Output:
Enter the dimension of the matrix:
3
2 3 1
4 5 1
1 1 1
The L Component is:
1.0 0.0 0.0
2.0 1.0 0.0
0.5 -1.0 1.0
The U Component is:
2.0 3.0 1.0
0.0 -1.0 -1.0
0.0 0.0 -0.5
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