Hi, It depends on the pulse sequence. Here is one I found written by Flemming Hanser where you can use odd numbers:
http://nmrwiki.org/psdb/kaylab/vnmrsys/psglib/CaHD_cpmg_GLY_dfh_600_v1.c Look for the comment: "ncyc can be either even or odd :)" Such sequences are probably in the minority though. Anyway, maybe we need a new user function. It would be good to have a series of user functions for specifying the experimental information. We already have that with: spectrometer.frequency relax_disp.exp_type relax_disp.relax_time relax_disp.cpmg_frq So keeping along these lines, maybe we need to have a relax_disp.cpmg_even_ncyc user function? Or we rename relax_disp.cpmg_frq to relax_disp.cpmg_setup and have that user function reserved for all CPMG pulse sequence info? What do you think? Renaming user functions does require a relax minor version number change though, so introducing it before relax 3.2.0 is a good idea. Regards, Edward On 4 May 2014 11:24, Troels Emtekær Linnet <[email protected]> wrote: > Hi Edward. > > The number of CPMG blocks has to be an even number. > > I remember this clearly, since I once did an CPMG experiment, with > some ncycs equal 4, 10, 15, 20, 25, ... > > And the intensities for all eksperiments with odd NCYC number was horrible. > > Kaare told me, that ncycs always has to be even. > That was something that Mikael Akke also have insisted on. > > But that day, I could not easily find it in the literature, so I left > it and accepted just another fact of NMR. > > And when I did the interpolated graphs with an odd-number of NCYC, > that looked weirdo. > Sig-saw all over the place. > > I actually think it could be a input check in relax, warning the user > if the number of CPMG blocks are not equal? > > And, I would be very happy to find it in the literature. :-) > Have you ever come around this? > > Best > Troels > > > > > > > > > > 2014-05-04 11:06 GMT+02:00 Edward d Auvergne > <[email protected]>: >> Follow-up Comment #2, bug #22008 (project relax): >> >> If this is a restriction of only the B14 analytic CPMG model >> (http://wiki.nmr-relax.com/B14), it would be best if only the B14 is >> affected. >> There is no need to restrict the numeric models based on the artificial >> limitation of an unrelated model. Maybe the best solution would be to check >> if the model is B14, and if so skip odd interpolation points? >> >> _______________________________________________________ >> >> Reply to this item at: >> >> <http://gna.org/bugs/?22008> >> >> _______________________________________________ >> Message sent via/by Gna! >> http://gna.org/ >> _______________________________________________ relax (http://www.nmr-relax.com) This is the relax-devel mailing list [email protected] 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
