Hi Brian
I think this might be due to the limit being set at 10.7ppm in Peak:Peak Finding in the Region Peak Find tab, if this is what it is then it caught me out to.
Cheers
Ben
On 29 May 2013, at 14:00, Brian Smith wrote:
> Hi,
>
> We're using fully updated v2.2 and recently noticed that crosspeaks close
> to 10 ppm don't get all their assignment possibilities listed in the
> assignment popup, nor when you make shift matched restraints. Peaks just
> below 10 ppm pick up potential assignments up to 9.somthing ppm while
> peaks 10 ppm and above pick up only assignments above 10.0 ppm. For a peak
> above 10 ppm, setting the assignment tolerances wider eventually starts
> picking up (presumably aliased) shifts at the other end of the scale.
>
> We can't track down any reason within the project as to why this should
> have arisen, but I'm suspicious of the quickShifts functionality in
> ccpnmr.analysis.core.AssignmentBasic. It seems to me that the different
> rounding of the shifts either side of position=10 to generate the keys for
> the quickShiftDict will mean that shifts just above 10 will have key=10
> while those below will have key=99 (and those between 1 and 1.1 will also
> have key=10?). If I understand the code right, the subsequent
> quickShiftDict.get(key) then won't pull out the 99s if called with a 10
> and vice versa?
>
> I'm guessing that you chose 10 as a cutoff for different treatment in
> order to get reasonable "density" of keys in 1H (mostly below 10 ppm) and
> heteronuclei (mostly above 10 ppm). Would it not be less risky to use just
> the first two significant figures as a key with a format and reconversion
> to float? This is probably rubbish, but maybe...
>
>
> float('%.2g' % position)
>
> There are a bunch of suggestions at
>
> http://stackoverflow.com/questions/3410976/how-to-round-a-number-to-significant-figures-in-python
>
>
>
> Dr. Brian O. Smith --------------------------- Brian Smith at glasgow ac uk
> Institute of Molecular, Cell and Systems Biology & School of Life Sciences,
> College of Medical, Veterinary & Life Sciences,
> Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
> Tel: 0141 330 5167/6459/3089 Fax: 0141 330 4600
> ----------------------------------------------------------------------
> The University of Glasgow, charity number SC004401
