RooFit in 20 Minutes Examples Are Badly Broken

The documentation on the “RooFit in 20 Minutes” webpage is badly wrong (or severely out of date). Can we please either remove the webpage or correct the documentation?

I specifically say broken, as the code examples routinely make reference to the wrong set of variables that are being used (e.g., using ‘x’ instead of ‘t’ in the example of convolution of two p.d.f.s), and throughout makes use of ‘w::’ to access factory objects, which does not work. I am unsure of the history of RooFit, so I assume that ‘w::’ worked back in 2008 and that at some time there was a backwards compatibility breaking change in the code to access objects in the way described here. However, if I am missing something and there is still some way to get ‘w::’ to work please let me know. Also, some the figures shown on the page do not match the code that is written.

The same problems apply to the RootFit Quick Start Guide on the RooFit manual webpage.

I know that there are other working sources of documentation out there, such as the RootFit Manual and plethora of presentations, but I feel that if documentation is going to be hosted on the ROOT website it should be up to date, especially as the “RooFit in 20 Minutes” page is so high in the search results on Google. I’ve attached working (in ROOT 6.09) versions of all the broken example code on the “RooFit in 20 Minutes” site, if that is helpful to correcting this.
likelihood.cpp (1.7 KB)
multiDimensional.cpp (1.49 KB)
convolution.cpp (986 Bytes)
Argus.cpp (940 Bytes)
Argus_long.cpp (1.39 KB)

Thanks for reporting - I have created


Thanks very much, Axel.

For future reference, should I have created a JIRA, or was this the appropriate place to raise the concern?


Doesn’t matter - if you’re sure it’s our bug and not yours :wink: then you are always welcome to open a Jira ticket! But we actually appreciate bug reports, so we’ll happily create a ticket ourselves if needed. OTOH, Jira tickets are a bit more nagging than forum posts, so if you really want to have something fixed, use Jira :slight_smile: