Problem with simultaneous fit of unbinned weighted dataset in RooFit

[amroo]

Hi everyone,
ROOT version: ROOT 6.22/02
I have four different datasets say wds1, wds2, wds3, wds4

Each of the 4 datasets is a combination of several weighted datasets. For example,

wds1 contains weighted dataset ds1, cds1, spds1 …

I am able to weight them successfully (https://root.cern/doc/master/rf403__weightedevts_8C.html) but when I combined these datasets for a simultaneous fit using:

RooDataSet combData("combData","combData",RooArgSet(M_dz,deltam),Index(acp),Import("d0ctp",wds1),Import("d0ctm",wds2),Import("d0bctp",wds3),Import("d0bctm",wds4));

Then the command:
RooFitResult *s1 = simPdf.fitTo(combData,Minos(1),NumCPU(4),Extended(1),Save(),SumW2Error(kTRUE));

disregards the weighting and fits the dataset as an unweighted one.
A similar problem was reported in the post below but without a solution:

Import dataset

Hi Experts, I’m doing a simultaneous fit following the example $ROOTSYS/tutorials/roofit/rf501_simultaneouspdf.C First of all I save all the results for the “separate fit” in some workspaces and I use two different Pdf to fit them using the same dataset but fitting over 2 different variables. Then to combine the result in the same fit: Import the weighted dataset twice renaming it in 2 different ways TFile *fitres = TFile::Open(“file.root”); RooDataSet rwDataset46 = (RooDataSet) fitres->…

[Axel]

Sadly our wonderful RooFit maintainer Stephan has moved on and we’re waiting for his successor to pick things up, some time 1st half next year. But I bet @moneta can help in the meantime!