#include <stdio.h>
//#include <cblas.h>

double m[] = {
  3, 1, 3,
  1, 5, 9,
  2, 6, 5
};

double x[] = {
  -1, -1, 1
};

double y[] = {
  0, 0, 0
};


  template <typename T>
 void cblas_dgemv(T*x, T*y)
 { for ( int i=0; i<3; ++i) 
    y[i]= x[i]*y[i]; }



int main(void)
{
  int i, j;

  for (i=0; i<3; ++i) {
    for (j=0; j<3; ++j) printf("%5.1f", m[i*3+j]);
    putchar('\n');
  }

  cblas_dgemv( *x, *y);


  for (i=0; i<3; ++i)  printf("%5.1f\n", y[i]);

  return 0;
}