Hi, Negative intensities are actually extremely common, especially for those experiencing fast relaxation. In the time course, exponential can often go below the noise level. At that point you have a white noise distribution about zero, so you have equal change of positive and negative values. This is no problem at all and such data should not be deselected. These noise points at the end also significantly help with the fitting by indicating to the optimisation algorithm that the curve should not be significant at these points.
Regards, Edward On 29 August 2014 15:22, Troels Emtekær Linnet <[email protected]> wrote: > Hi Edward. > > Is all intensities always positive? > > Some of our students tried, with a peak list which contained negative > intensities. > > Could spins with negative intensities be automatically de-selected? > > Or is intensities sometimes negative? > > best > > > > ---------- Forwarded message ---------- > From: <[email protected]> > Date: 2014-08-29 14:57 GMT+02:00 > Subject: r25432 - /trunk/specific_analyses/relax_disp/data.py > To: [email protected] > > > Author: bugman > Date: Fri Aug 29 14:57:38 2014 > New Revision: 25432 > > URL: http://svn.gna.org/viewcvs/relax?rev=25432&view=rev > Log: > Better error checking for the > specific_analyses.relax_disp.average_intensity() function. > > This function would fail with a traceback if a peak intensity error > analysis had not yet been > performed. Now it fails instead with a clean RelaxError so that the > user knows what is wrong. > > > Modified: > trunk/specific_analyses/relax_disp/data.py > > Modified: trunk/specific_analyses/relax_disp/data.py > URL: > http://svn.gna.org/viewcvs/relax/trunk/specific_analyses/relax_disp/data.py?rev=25432&r1=25431&r2=25432&view=diff > ============================================================================== > --- trunk/specific_analyses/relax_disp/data.py (original) > +++ trunk/specific_analyses/relax_disp/data.py Fri Aug 29 14:57:38 2014 > @@ -149,7 +149,7 @@ > # Error intensity data. > if error: > # Error checking. > - if not int_keys[i] in spin.peak_intensity_err: > + if not hasattr(spin, 'peak_intensity_err') or not > int_keys[i] in spin.peak_intensity_err: > raise RelaxError("The peak intensity errors are > missing the key '%s'." % int_keys[i]) > > # Sum. > > > _______________________________________________ > relax (http://www.nmr-relax.com) > > This is the relax-commits 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-commits > > _______________________________________________ > 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 _______________________________________________ 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
