|  | 
    determines the orientation of the points of the tuple A =     tuple [first,last) where A consists of d+1 points in
  d-space. This is the sign of the determinant
  
  where A[i] denotes the 
Cartesian
 coordinate vector of 
  the i-th point in A.
  | Precondition:  | size [first,last) == d+1 and 
  A[i].dimension() == d  ∀ 0  ≤ i  ≤ d.
   |  
 | Requirement:  | The value type of ForwardIterator is Point_d<R>. |   
         |