Hello RooFit experts,
My PDF = |sum_r[ a_r * A_r(m1,m2) ]|^2 / Norm; where r are several resonance components, a_r are fitting parameters, and A_r^i are constant mostly (allowing to update during the fit if resonance mass or width is free parameter) for the data point i of (m1,m2). Norm is normalization calcualted seperately and optimized using cache. For large number of dataset, the fit is too slow to calculate A_r^i repeatly in evaluate(). What in my mind is to cache these informations, but how to connect the information to each data point in evaluate()? Thanks in advance.
Regards,
Liming