From owner-chemistry%!at!%ccl.net Fri May 5 03:30:00 2006 From: "Michel Petitjean ptitjean . itodys.jussieu.fr" To: CCL Subject: CCL: Cartesian Coordinate Transformation Message-Id: <-31693-060504125240-17463-hE4Xlveg43nNh4U7mj4LGg~!~server.ccl.net> X-Original-From: Michel Petitjean Date: Thu, 4 May 2006 18:11:41 +0200 (MEST) Sent to CCL by: Michel Petitjean [ptitjean:-:itodys.jussieu.fr] To: "CCL Subscribers" Subject: CCL: Re: G: Cartesian Coordinate Transformation How many times should be published and republished the quaternion solution of the RMS problem ? Furthermore, it is simpler to use the vector expression of the quaternion rather than its 4*4 matricial formulation. There are practical details in my two papers in J.Math.Phys: 1999, 40(9), 4587-4595 (see the appendix) 2002, 43(8), 4147-4157 (see appendix A.5 for the extension to nfinite or/and continuous distributions of points) See also: http://petitjeanmichel.free.fr/itoweb.petitjean.shape.html Sent to CCL by: Paul Fleurat-Lessard [Paul.Fleurat-Lessard(a)ens-lyon.fr] > ... > As already mentionned, you can play with the iniertia tensor, but this=20 > can lead to orientation problem. I think that a more robust way is to=20 > use quaternion procedure as in the rmsd calculation. > You can find details in: > J Comput Chem 25: 1849 =AD1857, 2004, 'Using Quaternions to Calculate=20 > RMSD' , EVANGELOS A. COUTSIAS, CHAOK SEOK, KEN A. DILL > ... Michel Petitjean, Email: petitjean-,-itodys.jussieu.fr ITODYS (CNRS, UMR 7086) ptitjean-,-ccr.jussieu.fr 1 rue Guy de la Brosse Phone: +33 (0)1 44 27 48 57 75005 Paris, France. FAX : +33 (0)1 44 27 68 14 http://petitjeanmichel.free.fr/itoweb.petitjean.html