Xu, Xiuli (NIH/NHLBI) [E] <xux3 <at> nhlbi.nih.gov> writes: > > I would really appreciate it if someone can give suggestions on how to > do spectra fitting in R using ordinary least square fitting and > non-negativity constraints. The lm() function works well for ordinary > least square fitting, but how to specify non-negativity constraints? It > wouldn't make sense if the fitting coefficients coming out as negative > in absorption spectra deconvolution.
I don't see much reasons to use lm() to fit a spectrum, but if you want to do that, negative coefficients simply mean a shift by pi, sothe sign can be discarded for most practical purposed. But better look at one of the specialized packages like spectrino. Dieter ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
