On 11/7/06, Chris MacRaild <c.a.macraild@xxxxxxxxxxx> wrote:
Something of a side issue, I know, but this appears to be the
optimisation of a 3-parameter model to 3 data points. Hence the chi2
value of 0.
If you only have relaxation data at a single field strength,
optimisation of models m4 and m5 should be allowed as it is almost
standard. For example see
http://www.nmr-relax.com/refs.html#Mandel95. Equal parameters to data
points, although not ideal, is ok in mathematical modelling. The
problem is if there are more parameters than data points, then the
resultant optimised values are meaningless.
I thought we had coded residue selection to deselect residues in this
case. Any idea why it is apparently not happening here?
Not in this situation. Chris, the 'overfit_deselect()' function that
you coded deselects spins if there are only one or two data points in
total.
In any case, a quick workaround for the problem is to simply not
optimise models with more parameters than you have data points (even if
relax did ever give you results for these models, the results would be
meaningless).
Your 'overfit_deselect()' will already deselect the spin if this occurs.
Cheers,
Edward
Re: [bug #7641] Infinite Chi2 warning