Function: qnorm,q Purpose: calculate the norm a quaternion or an array of quaternions Inputs: q: a 4 element array, or an Nx4 element array, representing quaternion(s) Returns: norm(q): sqrt(a^2+b^2+c^2+d^2) or -1L on fail will be a single element or an N length array Notes: Implementation largely copied from the euve c library for quaternions Represention has q[0] = scalar component q[1] = vector x q[2] = vector y q[3] = vector z The vector component of the quaternion can also be thought of as an eigenvalue of the rotation the quaterion performs This implementation of norm does not apply the squareroot sometimes applied to a norm. If required the sqrt can easily be applied by the user Written by: Patrick Cruce(pcruce@igpp.ucla.edu) $LastChangedBy: pcruce $ $LastChangedDate: 2007-11-11 17:12:08 -0800 (Sun, 11 Nov 2007) $ $LastChangedRevision: 2027 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/ssl_general/trunk/cotrans/cotrans.pro $