/* 1 2 dot product (inner product) of two ranges
*/

#define DOT_R d[0]

static void rf_dot_callback( Data *d)
{
  d->DOT_R += eval_cell( d->cp_to, &d->to) * eval_cell( d->cp_from, &d->from);
}

double rf_dot(const Node *n, const Cell *c)
{
  Data d;

  Node *r1 = Right(n);
  Node *r2 = r1->next;

  if( check_range( r1, "dot: first argument")) return 0;

  if( check_range( r2, "dot: second argument")) return 0;

  d.DOT_R = 0;

  ss_traverse_range2_adjust( &r1->u.r, &r2->u.r, c, rf_dot_callback, &d);

  return d.DOT_R;
}