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Problem adding histograms in TBrowser

ROOT Version: v6-23-01-414-gb3ecdf6832
Platform: 64 bit Fedora 32 (5.6.19-300.fc32.x86_64)
Compiler: gcc version 10.1.1 20200507

I am not even able to perform what should be an extremely simple and intuitive operation in ROOT. I am trying to simply add two TH1F histograms in TBrowser.

After opening a ROOT file in the TBrowser , I select one of the histograms and then right-click to Add , I get the following warning:

Warning in <TRootContextMenu::Dialog>: data type is not basic type, assuming (int)

Following this, when I write the name of the same histogram in both the places of resulting panel, then I get the following error:

Error in <TClingCallFunc::IFacePtr(kind)>: Attempt to get interface while invalid.
Error in <TClingCallFunc::Exec(address, interpVal)>: Called with no wrapper, not implemented!

Am I doing anything fundamentally wrong?

You can use the histograms from this file: CL16.root (65.9 KB)


Please take a look at the Add method, it has nothing to do with the browser. If you want to display (draw) an histogram, you can either double-click on the histogram, or drag and drop it into the canvas. If you want to superimpose another histogram, type “SAME” in the “Draw Options” Combo box and double click on the histogram you want to superimpose.
BTW, there is a question-mark (?) on the right hand side of each context menu entry pointing to the html reference of the method associated to the menu entry.

To summarize, the Add method cannot be used from the TBrowser

Cheers, Bertrand.

Thank you. But, why is this (Add) feature is not available in the TBrowser?

BTW, when I click on the question-mark the TBrowser freezes, and there is no other way than kiiling root using pkill root to get rid of the frozen browser. Very strange!

OK, so there is a bug. I’ll investigate. And you’re right, the Add method should work or not be there. I’ll investigate too

I get the error mentioned in the first post here not only for Add but also for Divide. I request you to kindly check.

Do you also get frozen browser when you click in the question-mark?

Sure, I’ll check all the methods from all ROOT classes available from the context menus

Nope, it opens the html page in a TGHtml widget, but I’m working on Windows

It is possible that the ? problem is related to where the ROOT comes from. From my simple trials on Linux … it seems to me that there are real problems when ROOT is used directly from the build directory but there are possibly no problems when ROOT is used from the make install directory.

(... ROOT 6.22 from the "build" directory ...)
root [1] new TBrowser
(TBrowser *) 0x5650730d24a0
(... I click "?" in the TBrowser's canvas ...)
root [2] Warning in <TASImage::GetMask>: No image
Warning in <TASImage::GetMask>: No image
Warning in <TASImage::GetMask>: No image
Warning in <TASImage::GetMask>: No image
Warning in <TASImage::GetMask>: No image
Warning in <TASImage::GetMask>: No image

This time I didn’t understand what you mean by running ROOT from the build directory and install directory. Actually, I delete build directory immediately after installation. The ROOT executable is always in bin directory of the directory specified at the time of build. Therefore, I always run ROOT by sourcing thisroot.sh file from the directory where I have to work.

Could it be that - sometime due to very low internet connectivity the RTHML doesn’t show up which might be resulting in frozen TBrowser? Just for your reference, when I click ? next to the Add it takes me to https://root.cern.ch/root/html/TH1.html#TH1:Add page.

Shouldn’t there be offline help available for ROOT on local computer?

The build directory means that you have not executed make install (in both cases, there exists “bin/thisroot.sh” which one needs to source).
Anyhow, I am not sure that my “observations” are correct.

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