Best way to obtain the latest version of Minuit2 stand alone

Roofit and RooStats
1

Hi,
I have an external application (github.com/giacomov/3ML) which can be used to fit models to astronomical data.

It can use Minuit2 from ROOT (through pyROOT), or the standalone version 2.5 through an ad-hoc wrapper (github.com/iminuit/iminuit).

The performances of the two are different, and the ROOT version gives consistently better results (it converges to a better minimum).

I would like to know if and where I can find a standalone version of Minuit2 that is exactly the same as the current version of ROOT, so we can use it in place of the one we have right now in iminuit.

Thanks!

2

Hi,

The C++ version of Minuit2 standalone that you can get is a bit old (around 2-3 years) and you can get at this link
cern.ch/mathlibs/sw/5_34_14/ … .14.tar.gz

If you need I can make a more recent version based on ROOT 6.08

The changes however are very minor, so you should not really see a difference with respect to the current one.
The only new feature added is the possibility to do not store all the state information for each iteration to save memory usage. This is relevant with fit with a very large number of parameters (let’s say much greater than 100).

Best Regards

Lorenzo

3

well, if it’s not too time-consuming to make a new version, it would be great to have exactly the version in ROOT available as standalone, thanks!

Then, supposing that doesn’t solve the difference, I can investigate where the difference comes from comparing apples to apples.

4

I’ve made a copy of standalone Minuit 2 from the ROOT 6.08.04 source, with a CMake build system. It is at https://github.com/GooFit/Minuit2. The examples build, I haven’t had a chance yet to test it in a larger system (GooFit).