Re: Error in consistency testing function F_R2Re: Error in consistency testing function F_R2Hi Ed, This is a good point. Is the CSA value for 13C positive or negative ? For F_eta, it may only affect the sign of the obtained value, thus not changing the analysis (comparison between different fields). For J(0), the analysis shouldn't be affected also as the square values are used. For F_R2 also, the square values are used, thus the analysis wouldn't be affected. Nevertheless, there will be a need for a redesign of the equations so they are eaiser to use and more flexible in regards to the gyromagnetic ratio or CSA and dipolar constants used... I put this on my 'todo' list ! Cheers, Séb Edward d'Auvergne wrote:
Would this be a problem if carbon is being looked at rather than nitrogen? In this case, gC is positive and the dipolar constant is negative. For the CSA value, this could be negative or positive, changing the CSA constant. Would this affect the analysis? Regards, Edward On Fri, Jul 4, 2008 at 4:09 PM, Sébastien Morin <sebastien.morin.1@xxxxxxxxx> wrote:Hi again, I realized that even though the gN value was negative in eta, the CSA value (o_par - o_per) being also negative would make eta positive... Indeed, figures in the Fushman paper show positive values of F_eta, thus positive values of eta... Thus, eta is positive and no further change is needed in the consistency tests code... except for what you proposed about putting eta in ri.py and ri_comps.py... Cheers, Séb Sébastien Morin wrote:Hi Ed, You're absolutely right. I'll change the code right away so eta becomes negative as it should be. Cheers, Séb Edward d'Auvergne wrote:For future extensibility and compatibility, trying be as technically accurate as possible would be best. For example in the future the eta code could be shifted into the ri.py and ri_comps.py files to allow full model-free analysis (and spectral density mapping) using the additional cross correlated relaxation rates eta_z and eta_xy. So if eta should physically be negative then I think we should observe that, even if it makes no difference in the consistency testing code. Cheers, Edward On Thu, Jul 3, 2008 at 11:53 PM, Sébastien Morin <sebastien.morin.1@xxxxxxxxx> wrote:Hi Ed, Good ! For the negative sign, Fushman described the dipolar constant as d = - (u0/4pi) gH gN h / (4pi r^3). Hence, the negative sign introduced by gN is neutralized there by a '-' sign... For the CSA constant, however, there is no '-' sign in the equation and the negative sign introduced by gN should be still present... Hence, for eta, I should add a '-' sign in the equation for our definition (in relax) being the same as in Fushman. Again, however, this would change consistency evaluation since it would only inverse the obtained values (+ to -). Am I right ? If so, I should commit a change where eta = [...] would become eta = - [...] Cheers, Séb Edward d'Auvergne wrote:Ah, now I get it. I should really get around to changing these functions so that there is one function for the dipolar constant, and one for constant squared (and the same thing for the CSA constant). Be careful with the square root of the dipolar contant squared though, unsquared it should have a negative sign at the front. Regards, Edward On Thu, Jul 3, 2008 at 8:01 PM, Sébastien Morin <sebastien.morin.1@xxxxxxxxx> wrote:Hi Ed, I double-checked once more the equations in Fushman and here what it is : c = gN . B0 . (o_par - o_per) / 3 = wN . CSA / 3 since : c^2 = (wN . CSA)^2 / 9 = c' / 3 c = (c' / 3)**0.5 where c is the constant defined by Fushman and c' is the one we use in relax and which is normally seen everywhere. That said, any appearance of c in Fushman should be replaced by (c' / 3)**0.5 in relax (the squared root of : c' / 3). This affects eta : eta = dc [4 J(0) + 3 J(wN)] P_2 = (d' . c' / 3)**0.5 [4 J(0) + 3 J(wN)] P_2 and also F_R2 F_R2 = ( R2 - P_HF ) / {4 + 3 / [ 1 + (wN . tc)^2 ] } [d^2 + (wN . CSA / 3)^2] = ( R2 - P_HF ) / {4 + 3 / [ 1 + (wN . tc)^2 ] } [d^2 + c^2] = ( R2 - P_HF ) / {4 + 3 / [ 1 + (wN . tc)^2 ] } [d^2 + c^2] = ( R2 - P_HF ) / {4 + 3 / [ 1 + (wN . tc)^2 ] } [d' + (c' / 3)] These definitions of eta and F_R2 are those implemented in relax. They seem to work fine with my experimental data. Removing the 1/3 factor from the equations doesn't affect F_eta consistency since this only scales the obtained value by a fixed amount independent of the magnetic field. However, removing the 1/3 factor from F_R2 changes drastically the obtained values and then data from different fields seem scaled linearly with the magnetic field... Thus, I'm pretty sure that these equations are right as consistency evaluation using them seems to work fine with some consistency between the different functions (J(0), F_eta and F_R2). Cheers, Séb Edward d'Auvergne wrote:Hi, Are you really sure Fushman defines it in that way is this manuscript? It's normally defined as you say 1) c = (CSA * wN)/sqrt(3) and in the function called by your consistency testing code, the square of this is returned (as an aside, I should document that function better). Assuming the CSA constant 2) c' = (CSA * wN)/3, and the equation 3) f_r2 = (r2 - p_hf) / ((4.0 + 3.0 / (1 + (wN * tc) ** 2)) * (d + c/3.0)) then the last multiplication factor becomes 4) x = d + c'/3, 5) x = d + (CSA * wN) / 9. The last part of 5) is the CSA constant of 1) divided by the 3 times the square root of 3 (3*sqrt(3)). I have a feeling that there is an error in the constant definitions somewhere. Do you know if the normal CSA constant divided by 3*sqrt(3) is correct for the f_r2 value? If the division by 3 is removed, then this is the CSA constant divided by sqrt(3), which again seems not quite right. Unfortunately I don't have Fushman's publication at hand to check the constants in his derivations. I think this derivation needs to be very carefully scrutinised for accidental typos. Regards, Edward On Wed, Jun 25, 2008 at 8:59 PM, Sébastien Morin <sebastien.morin.1@xxxxxxxxx> wrote:Hi, Well... I'm not that sure this was an error as the CSA constant, in the Fushman paper is not defined as in relax : Fushman c = (CSA wN)/3 relax c = (CSA wN)^2/3 In fact, I thought that Fushman had defined c as : c = (CSA wN)/sqrt(3) Hence, I removed the division by 3 in revision 6499 for the definition of F_R2. This was an error and should have stayed in the code... I will revert this right now. her candidat, Dans le cadre de la campagne de recrutement des astronautes, nous avons fait un premier tri parmi les 5351 candidatures reçues. Suite à l'information que vous avez fournie, nous sommes heureux de vous annoncer que le comité de présélection a jugé que vous rencontriez les critères de mérite utilisés. Afin de poursuivre le processus, nous avons besoin d'informations supplémentaires. Nous vous demandons donc de compléter le deuxième formulaire électronique qui sera accessible sur notre site Web à partir du mercredi 9 juillet 2008 à 8 h, heure avancée de l'Est (UTC - 4 h), à l'adresse suivante : https://f2.space.gc.ca Vous avez jusqu'au lundi 28 juillet 2008 à 18 h, heure avancée du Pacifique (UTC - 7 h), pour compléter votre dossier en ligne. Il est de votre intérêt et de votre responsabilité de répondre le mieux et le plus complètement possible à toutes les questions. Si vous n'avez pas répondu dans les délais prévus aux présentes demandes, nous considérerons que vous avez volontairement retiré votre candidature du présent processus de recrutement. Le comité de présélection révisera toutes les candidatures et identifiera les candidats les plus qualifiés pour le poste d'astronaute. Les résultats de ce deuxième tri commenceront à être divulgués par vague de août à septembre. Les personnes sélectionnées pour poursuivre l'évaluation seront convoquées en septembre pour des entrevues qui se tiendront en octobre 2008. Afin de vous aider à préparer l'information requise, vous trouverez sur cette page un résumé de l'information que vous devrez fournir à partir du 9 juillet prochain dans le deuxième formulaire électronique : http://www.espace.gc.ca/asc/fr/astronautes/recrutement_form2.asp Nous vous souhaitons bonne chance. Veuillez agréer nos meilleures salutations, Le comité de présélection du recrutement des astronautes Campagne de recrutement des astronautes Agence spatiale canadienne 6767, route de l'Aéroport, Saint-Hubert QC J3Y 8Y9 Téléphone (de 8 h à 18 h heure avancée de l'Est (UTC - 4 h) du lundi au vendredi) : - au Canada 1-888-225-8040 - de l'extérieur du Canada 450-926-5888 Courriel ra-ar@xxxxxxxxxxx Site Web www.space.gc.ca Gouvernement du Canada Please forget these revisions and these two mails... Ciao ! Séb :) P.S. Ah... The joys of constants definitions !!! Sébastien Morin wrote:Hi, I realized, when looking at the equations for consistency testing that there was an error concerning F_R2. This was related to the CSA constant. This is now corrected (revision 6499). Should we make a new release to correct this error ? Regards, Séb _______________________________________________ relax (http://nmr-relax.com) This is the relax-devel mailing list relax-devel@xxxxxxx 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-devel_______________________________________________ relax (http://nmr-relax.com) This is the relax-devel mailing list relax-devel@xxxxxxx 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-devel_______________________________________________ relax (http://nmr-relax.com) This is the relax-devel mailing list relax-devel@xxxxxxx 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-devel_______________________________________________ relax (http://nmr-relax.com) This is the relax-devel mailing list relax-devel@xxxxxxx 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-devel