More than one fit in the same Jupyter cell hangs

Dear PyROOT experts,

I recently updated to ROOT 6.06/04 and I found that if I try to fit more than one histogram in the same cell of a Jupyter notebook the program seems to hang.

I provide a small example with which I can reproduce the issue on my system. I am running Jupyter 4.1:

CELL 1:
import ROOT

CELL 2:
h = ROOT.TH1F(“gauss”,“Example histogram”,100,-4,4)
h.FillRandom(“gaus”)
h2 = ROOT.TH1F(“gauss”,“Example histogram”,100,-4,4)
h2.FillRandom(“gaus”)

CELL 3:
h.Fit(“gaus”, “S”)
h2.Fit(“gaus”, “S”)

In CELL 3 if one of the two fits is commented out the code runs fine and I see the output. If I try to run both I never see any output and the kernel shows a busy status and never gives any response. There is also no output printed to the terminal.

Do you know if this is expected or if there is any workaround?

Thank you in advance for any help.

Hi,

I on what platform did you verify this behaviour?

Danilo

Hi Danilo,

I am running on mac os, Yosemite 10.10.5. I installed root via the binary package:

| Welcome to ROOT 6.06/04 root.cern.ch |
| © 1995-2016, The ROOT Team |
| Built for macosx64 |
| From tag v6-06-04, 3 May 2016 |

Try ‘.help’, ‘.demo’, ‘.license’, ‘.credits’, ‘.quit’/’.q’

Is there any other information that could be useful to debug this?

Marco

Hi Marco,

I cannot reproduce in the development releases (6.07). We’ll come back to you with more info about the 6.06 ones.

Cheers,
Danilo