/* http://www.edcc.edu/faculty/paul.bladek/Cmpsc142/matmult.htm */
int program(int argc, string[] argv)
{
   var a = new int[][]{new int[]{1, 3, 4},
                       new int[]{2, 0, 1}};
   var b = new int[][]{new int[]{1, 2, 3, 1},
                       new int[]{2, 2, 2, 2},
                       new int[]{3, 2, 1, 4}};
   var c = new int[][]{new int[]{0, 0, 0, 0},
                       new int[]{0, 0, 0, 0}};

   matrix_Mult(a, b, c);
   prnNx4(c, 2);
   
   matrix_MultAlt(a, b, c); /* alternate form that calls dot3 */
   prnNx4(c, 2);  
   return 0;
} 

/* http://www.edcc.edu/faculty/paul.bladek/Cmpsc142/matmult.htm */
void matrix_Mult(int[][] a1, int [][] a2, int [][] a3)
{
   for(var i = 0; i < 2; i=i+1;)  {
      for(var j = 0; j < 4; j=j+1;) {
          for(var k = 0; k < 3; k=k+1;) {
              a3[i][j] = a3[i][j] + a1[i][k] * a2[k][j];
	  }
      }
   }
   return;
}

/* http://www.edcc.edu/faculty/paul.bladek/Cmpsc142/matmult.htm */
void matrix_MultAlt(int[][] a1, int[][] a2, int[][] a3)
{
  for(var i = 0; i < 2; i=i+1;) {
    for(var j = 0; j < 4; j=j+1;) {
           a3[i][j] =  dot3(a1, a2, i, j);
    }
  }
  return;
}

/* http://www.edcc.edu/faculty/paul.bladek/Cmpsc142/matmult.htm */
int dot3(int[][] a1, int[][] a2, int row, int col)
{
    var sum = 0;
    for(var k = 0; k < 3; k=k+1;) {
      sum = sum + a1[row][k] * a2[k][col];
    }
    return sum;
}

/* http://www.edcc.edu/faculty/paul.bladek/Cmpsc142/matmult.htm */
void prnNx4 (int[][] ar, int n)
{
    for(var i = 0; i < n; i=i+1;)
    {
        for(var j = 0; j < 4; j=j+1;)
        {
            print_int(ar[i][j]);
            print_string (" ");
        }
        print_string("\t"); 
    }
    return;
}