ANGLE2POINTS Compute horizontal angle between 2 points.

   ALPHA = angle2Points(P1, P2),
   Pi are either [1*2] arrays, or [N*2] arrays, in this case ALPHA is a 
   [N*1] array. The angle computed is the horizontal angle of the line 
   (P1 P2)
   Result is always given in radians, between 0 and 2*pi.

   See Also:
   points2d, angles2d, angle3points, normalizeAngle, vectorAngle


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 Author: David Legland
 e-mail: david.legland@grignon.inra.fr
 created the 02/03/2007.
 Copyright 2010 INRA - Cepia Software Platform.

Package: matgeom