Java Program for Kronecker Product of two matrices
Given a matrix A and a matrix B, their Kronecker product C = A tensor B, also called their matrix direct product, is an matrix.
A tensor B = |a11B a12B|
|a21B a22B|
= |a11b11 a11b12 a12b11 a12b12|
|a11b21 a11b22 a12b21 a12b22|
|a11b31 a11b32 a12b31 a12b32|
|a21b11 a21b12 a22b11 a22b12|
|a21b21 a21b22 a22b21 a22b22|
|a21b31 a21b32 a22b31 a22b32|
Examples:
1. The matrix direct(kronecker) product of the 2×2 matrix A
and the 2×2 matrix B is given by the 4×4 matrix :
Input : A = 1 2 B = 0 5
3 4 6 7
Output : C = 0 5 0 10
6 7 12 14
0 15 0 20
18 21 24 28
2. The matrix direct(kronecker) product of the 2×3 matrix A
and the 3×2 matrix B is given by the 6×6 matrix :
Input : A = 1 2 B = 0 5 2
3 4 6 7 3
1 0
Output : C = 0 5 2 0 10 4
6 7 3 12 14 6
0 15 6 0 20 8
18 21 9 24 28 12
0 5 2 0 0 0
6 7 3 0 0 0
Below is the code to find the Kronecker Product of two matrices and stores it as matrix C :
Java
import java.io.*;
import java.util.*;
class GFG {
static int cola = 2 , rowa = 3 , colb = 3 , rowb = 2 ;
static void Kroneckerproduct( int A[][], int B[][])
{
int [][] C= new int [rowa * rowb][cola * colb];
for ( int i = 0 ; i < rowa; i++)
{
for ( int k = 0 ; k < rowb; k++)
{
for ( int j = 0 ; j < cola; j++)
{
for ( int l = 0 ; l < colb; l++)
{
C[i + l + 1 ][j + k + 1 ] = A[i][j] * B[k][l];
System.out.print( C[i + l + 1 ][j + k + 1 ]+ " " );
}
}
System.out.println();
}
}
}
public static void main (String[] args)
{
int A[][] = { { 1 , 2 },
{ 3 , 4 },
{ 1 , 0 } };
int B[][] = { { 0 , 5 , 2 },
{ 6 , 7 , 3 } };
Kroneckerproduct(A, B);
}
}
|
Output :
0 5 2 0 10 4
6 7 3 12 14 6
0 15 6 0 20 8
18 21 9 24 28 12
0 5 2 0 0 0
6 7 3 0 0 0
Time Complexity: O(rowa*rowb*cola*colb), as we are using nested loops.
Auxiliary Space: O((rowa + colb)*(rowb + cola)), as we are not using any extra space.
Please refer complete article on Kronecker Product of two matrices for more details!
Last Updated :
25 Apr, 2022
Like Article
Save Article
Share your thoughts in the comments
Please Login to comment...