ANGLE3POINTS Compute oriented angle made by 3 points.

   ALPHA = angle3Points(P1, P2, P3);
   Computes the angle between the points P1, P2 and P3.
   Pi are either [1*2] arrays, or [N*2] arrays, in this case ALPHA is a 
   [N*1] array. The angle computed is the directed angle between line 
   (P2P1) and line (P2P3).
   Result is always given in radians, between 0 and 2*pi.

   See Also:
   points2d, angles2d, angle2points


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 Author: David Legland
 e-mail: david.legland@grignon.inra.fr
 created the 23/02/2004.
 Copyright 2010 INRA - Cepia Software Platform.

Package: matgeom