ISPARALLEL3D Check parallelism of two 3D vectors.

   B = isParallel3d(V1, V2)
   where V1 and V2 are 2 [1x3] arrays, returns 1 if the vectors are
   parallels, and 0 otherwise.

   Also works when V1 and V2 are two [Nx3] arrays with same number of
   rows. In this case, return a [Nx1] array containing 1 at the positions
   of parallel vectors.

   Also works when one of V1 or V2 is scalar and the other one is [Nx3]
   array, in this case return [Nx1] results.

   B = isPerpendicular3d(V1, V2, TOL)
   Specifies the absolute tolerance (default is 1e-14).

   Example
   isParallel3d([1 2 1], [2 4 2])
   ans =
       1

   isParallel3d([1 2 1], [1 3 2])
   ans =
       0

   See also
   vectors3d, isPerpendicular3d

 ------
 Author: David Legland
 e-mail: david.legland@grignon.inra.fr
 Created: 2006-04-25
 Copyright 2006 INRA - CEPIA Nantes - MIAJ (Jouy-en-Josas).

Package: matgeom