Implementation of matrix multiplication and normalization in C program

Matrix Multiplication

Now discuss the process of matrix multiplication. Matrix multiplication can only be performed if certain conditions are met. Suppose the two matrices are P and Q, and their dimensions are P (a x b) and Q (z x y), the resulting matrix can be found if and only if b = x. Then the order of the resulting matrix R will be (m x q).

Algorithm

matrixMultiply(P, Q):
Assume dimension of P is (a x b), dimension of Q is (z x y)
Begin
   if b is not same as z, then exit
   otherwise define R matrix as (a x y)
   for i in range 0 to a - 1, do
      for j in range 0 to y – 1, do
         for k in range 0 to z, do
            R[i, j] = R[i, j] + (P[i, k] * Q[k, j])
         done
      done
   done
End

Matrix normalization

Suppose we have a 2x3 matrix:
4 5 6
1 2 3 The normalized matrix would be:
4/sqrt(pow(5,2) + pow(6,2)) 5/sqrt(pow(5,2) + pow(6,2)) 6/sqrt(pow(5,2) + pow(6,2))
1/sqrt(pow(2,2) + pow(3,2)) 2/sqrt(pow(2,2) + pow(3,2)) 3/sqrt(pow(2,2) + pow(3,2))

Example

#include <stdio.h>
#include <math.h>
int main() {
   int row, col, row1, col1;
   int assignMatrix[50][50], rowAdd[100] = {0};
   long long int a, square[50] = {0};
   double norm[50][50], k;
   printf("Enter size of a matrix</p><p>");
   scanf("%d %d", &row, &col);
   printf("Enter matrix of size %dX%d</p><p>", row, col);
   for ( row1 = 0; row1 < row; row1++) {
      for (col1 = 0; col1 < col; col1++) {
         scanf("%d", &assignMatrix[row1][col1]);
      }
   }
   printf("</p><p>rows: %d cols: %d elements:</p><p>",row,col);
   for( row1 = 0; row1 < row; row1++) {
      for( col1 = 0; col1 < col; col1++) {
         printf("%d ", assignMatrix[row1][col1]);
      }
      printf("</p><p>");
   }
   for (row1 = 0; row1 < row; row1++) {
      for (col1 = 1; col1 < col; col1++) {
         a = assignMatrix[r][c];
         square[row1] += a * a;
      }
      printf("Sum of squares of row %d: %lld</p><p>",row1,square[row1]);
   }
   for ( row1 = 0; row1 < row; row1++ ) {
      k = 1.0 / sqrt(square[row1]);
      for( col1 = 0; col1 < col; col1++ ) {
         norm[row1][col1] = k * assignMatrix[row1][col1] ;
      }
   }
   printf("</p><p>Normalized Matrix:</p><p>");
   for( row1 = 0; row1 < row; row1++) {
      for( col1 = 0; col1 < col; col1++) {
         printf("%.3lf ", norm[row1][col1]);
      }
      printf("</p><p>");
   }
   return 0;
}

Output

Enter size of a matrix
2
3
Enter matrix of size 2X3
4 5 6
1 2 3
rows: 2 cols: 3 elements:
4 5 6
1 2 3
Sum of squares of row 0: 61
Sum of squares of row 1: 13
Normalized Matrix:
0.512 0.640 0.768
0.277 0.555 0.832
Process returned 0 (0x0) execution time : 12.446 s
Press any key to continue.

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