Thread: Matrice Recursive Determinant Calculation

Hi i have problems calculating the determinant of more than a 2 x2 can anyone help

Code:

 nt determinant(int matrix_temp[10][10],int size_matrice)   //Get the minor of the matrice
{
 int i,j,determinant_sum = 0;
 int matrice[10][10];//matrice[maximum][maximum]
 if(size_matrice==2)
  {                                        //basic step
	determinant_sum = matrix_temp[0][0]*matrix_temp[1][1] - matrix_temp[0][1]*matrix_temp[1][0];
	return determinant_sum;
  }
 for(int count=0;count<size_matrice;count++)
 {
  int h = 0,k = 0;
  for(i=1;i<size_matrice;i++)
  {
	for( j=0;j<size_matrice;j++)
	{
	 if(j==count)
	  
	 matrice[h][k] = matrix_temp[i][j];
	 k++;
	 if(k == size_matrice-1)
	  {
		 h++;
		 k = 0;
	  }

	}
  }



//recursive formula
  determinant_sum = determinant_sum + matrix_temp[0][count]*pow(-1,count)*determinant(matrice,size_matrice-1);
  //Force the sum to return an "int" result 
 
 }
 return determinant_sum;
}

You managed to not write down the recursive formula very well, in that putting the word "sum" in a variable name does not make the program give you a sum. For instance in a 3x3 matrix you would need to compute
matrix_temp[0][0]*pow(-1,0)*determinant(minor(matrix_temp, 0, 0), 2) +
matrix_temp[0][1]*pow(-1,1)*determinant(minor(matrix_temp, 0, 1), 2) +
matrix_temp[0][2]*pow(-1,2)*determinant(minor(matrix_temp, 0, 2), 2)

Notice in your code that only one of those lines happens. Notice also that you will have to write a function to get the minor, and that the function to get the minor has to know which row and which column to eliminate.