Hi Stefano, On Fri, 8 Jul 2005, Stefano Ciurli wrote:
Hi Bruce and Matt, just thinking while fitting: wouldn't it be possible-better-auspicable-desirable to have a simultaneous fit in both R and k space and evaluate the statistics of the two fits in some intelligent way? Just a though Stefano
Trying fits that simultaneously uses R- and Q-space is an OK idea, and like Bruce says, isn't very different from using multiple k-weights. I think it would be really interesting to fit in the "R+Q" space generated by the wavelet transforms. For now, I sort of doubt that fitting in R-space and Q-space simultaneoulsy will make a huge difference to fitting in R-space alone, but I'd be curious to see evidence either way. On the other hand, fitting unfiltered k-space is always a bad idea. Using R-space and Q-space allows you to select the k- and R-range of your data to model, which you want. This also allows a proper error analysis. Using unfiltered k-space does not allow this as there are systematic signals (the higher shells) in the data that are not modelled. Fitting in unfiltered k-space also gives erroneous R-factors, as was recently discussed here. Cheers, --Matt