Problem with RDataFrame::Fill in python

[simonepigazzini]

Hello,

I am facing an issue calling the Fill method of an RDataFrame in python, after loading a TTree into the RDataFrame what I do is:

hist = ROOT.TH1D("h_trk_y", "", 100, -20, 20)
filled_hist = h4df.Fill(test_h, 'trk_y')

The error I get is:

TypeError: can not resolve method template call for ‘Fill’

Using Histo1D works fine on the same column but I would like to use the Fill method in order to add weights to the histogram. I have also tried to place the histogram definition inside the Fill call and got the same error.

Is there a general issue with Fill and the python bindings of RDataFrame or is there I way how I can debug this further?

Thank you in advance,

simone

PS: I am running on the CERN SWAN with this configuration:
LGC 96python3
CC7 (gcc8)

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[simonepigazzini]

Sorry, I have just noticed that weighted histograms can be created with Histo1D, so I can use that to quickly fix the issue. Anyway do you have an idea of why Fill is failing.

Thank you,

simone

[eguiraud]

Hi Simone,
good that you found a solution. @etejedor might know what’s up with the template argument deduction through the python bindings (but, admittedly, that’s not the most robust side of PyROOT).

Cheers,
Enrico

[etejedor]

Hi Simone,
The issue you describe looks like a bug. I opened the following ticket to follow it:

https://sft.its.cern.ch/jira/browse/ROOT-10396

The second parameter needs to be of type ColumnNames_t (aka std::vector or initializer list), but even with the small correction the example you provide fails.

[simonepigazzini]

@eguiraud, @etejedor,

thank you for looking into this.

simone