RooSimPdfBuilder with 2 prototype pdfs

Solved!

The problem is that you have to feed the ingredient pdfs of the RooSimultaneous to the RooSimPdfBuilder constructor e.g:

RooSimPdfBuilder mgr(DC, gauss_1, gauss_2.....) ;

Not just the RooSimultaneous itself e.g:

RooSimPdfBuilder mgr(simPdf) ;

The solution was found here:

root.cern.ch/root/html510/src/R … r.cxx.html

Thanks to those that replied!

S