Convolution of a function to a resol function with E depend

[wingto911]

I found a solution here, (but it’s a bit slow)

RooFFTConvPdf: Resolution depends on convolution observable

Hi, I have a question regarding the behaviour of RooFFTConvPdf which probably stems from an inherent misunderstanding of how the convolution process works, but here goes. I want to convolve a “physics” pdf with another “resolution” pdf which depends on the value of the physics pdf observable. More concretely, if the observable is x, I want to convolve with a gaussian with a width which varies as a function of x. i.e. f(x) (x) g(x’;mean = 0, sigma(x)) Here x and x’ refer to the same observabl…

But the method uses RooProdPDF.createProjection method. It looks like this is done using numeric integration. This causes the codes to take ~ 3 minutes to run instead of the RooFFTConv < 10 seconds. Does anyone have experience with speeding up this creatProjection method?

Thanks,