Which Minuit2 version/patch_level/commit is used in iminuit?

[JacekHoleczek]

As of today (2023.11.06), the last iminuit release is v2.24.0 (2023.08.15).
I cannot find any place that says which Minuit2 version/patch_level/commit it incorporates.
Well, the last Minuit2 improvements/fixes are just two weeks old (2023.10.25).

[HDembinski]

The ROOT version against which iminuit is built is shown on the frontpage of the docs. iminuit is occasionally updated to the latest ROOT version. We don't do this regularly, because most of the changes in Minuit2 are not relevant to us.
We have our own extensive suite of unit tests to ensure that iminuit works correctly.

Unless you have a specific fix in mind that you want to see in iminuit, I think you shouldn't worry about this.

[HDembinski]

In fact, often the "improvements" in ROOT are adding new bugs, which then creates work for me to write workarounds in iminuit. This is why I don't update the C++ code regularly.

To demonstrate: I just updated ROOT to current main and now a test which was passing before fails and it is a bug in C++ that was introduced by the ROOT devs.

[JacekHoleczek]

It seems to me that it would really be a good idea to keep the Minuit2 version up-to-date (reporting any found problems/errors back to ROOT).

I've seen a "report" (during a non-public collaboration meeting) that "SIMPLEX" in iminuit gave "bad results" (when compared to the same method in ROOT). I did not try to follow this "report", nor I tried to play with it (I don't think it would be easy to create a "standalone reproducer").

[HDembinski]

That's exactly what is happening, I already fixed several bugs in Minuit2 in ROOT, you can check my PRs in the ROOT repo.

That being said, it is not in my interest to create more work for myself and therefore iminuit won't be regularly updated to the latest ROOT version. In recent years there have been no fundamental changes to the core Minuit2 code that made it worthwhile to update frequently.