sPlot with non-floating yields


Is it possible to use the existing sPlot tool for the case of a fit in which some of the yields are not independently varying parameters? Here’s a simplification of the problem I’m facing: assume the fit involves three PDFs A, B and C, but the yield of C is constrained to be 10% of the yield of A. C is considered a background, and due to a quirk in the fit its yield can’t be left to float.

I think that the original paper (http://arxiv.org/abs/physics/0402083) mentions this case in Appendix B. As far as I can see it is not in the code - but maybe I’m missing something.