Edward d'Auvergne wrote: > On Thu, Mar 12, 2009 at 6:05 PM, Sébastien Morin > <sebastien.mori...@ulaval.ca> wrote: > >> Hi, >> >> In an attempt to find the problem causing this bug, I dug into the code >> and found something which could be erroneous... This alone does not fix >> the bug, but may be part of the fix (or not)... >> >> In function math_fns/direction_cosine.calc_ellipsoid_di(), there could >> be an error at line 229: >> >> diff_data.dz[1] = data.sin_b * data.sin_g >> >> If I am right (?), this part of the code is related to page 193 of >> Edward d'Auvergne's thesis: >> >> c11 = diff_data.dx[0] >> c21 = diff_data.dx[1] >> c31 = diff_data.dx[2] >> >> c12 = diff_data.dy[0] >> c22 = diff_data.dy[1] >> c32 = diff_data.dy[2] >> >> c13 = diff_data.dz[0] >> c23 = diff_data.dz[1] --> FALSE !!!! >> c33 = diff_data.dz[2] >> >> Indeed, >> c23 = sin(beta) * cos(gamma), >> whereas >> diff_data.dz[1] = data.sin_b * data.sin_g >> >> >> Thus, either me, the code or Edward's thesis are erroneous here... >> >> Am I right ? >> > > These unit vectors are the columns of the reverse matrix, or the > transpose, or simply rows of the normal matrix. This depends if you > are defining the rotation from being from the diffusion tensor frame > to the lab frame or the reverse - both are related by the transpose. > Hence this value is c32 which in my thesis is sin(alpha)*sin(beta). > Does this answer your question and solve the issue? There could be > bugs elsewhere in here though because of this. > > Ok... I am far from an expert in trigonometry... :p
If I understand well what you wrote, there is no error in the code or the thesis ? Or should something be corrected ? Regards, Séb > Regards, > > Edward > > -- Sébastien Morin PhD Student S. Gagné NMR Laboratory Université Laval & PROTEO Québec, Canada _______________________________________________ relax (http://nmr-relax.com) This is the relax-users mailing list relax-users@gna.org To unsubscribe from this list, get a password reminder, or change your subscription options, visit the list information page at https://mail.gna.org/listinfo/relax-users
