Issues installing ROOT with Python support

[Saumyenk]

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ROOT Version: 6.24/06 and 6.28/0
Platform: Ubuntu 20.04
Compiler:

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Hi,
I was trying to install ROOT with Python support. I already have one installation that works fine.
First I tried to rebuild the same version (v6.24/06) with Python3. That compiled fine without any error but when I was trying to import ROOT from Python it gives an error.

The commands I used for the installation are as follows

cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 ../root_src
sudo cmake --build . --target install -- -j5

I tried both the Python, the one at /usr/bin and the one in the conda environment. Both gave the same error.

Then I tried the conda installation to keep things simple. It also got installed without any error. The commands I used are the following:

conda deactivate
conda config --set channel_priority strict
conda create -c conda-forge --name icts_root root

But again when I tried to run the ROOT by the command root or through Python importing root via import ROOT, I got the following error.

Could you help me install it successfully so that I am able to use pyROOT using a Jupyter notebook.

I thank you for any possible help in this regard.

With regards,
Saumyen

[bellenot]

Maybe @vpadulan or @eguiraud can help with this

[Saumyenk]

Thank you so much @bellenot for your response and referral.

@vpadulan and @eguiraud, would you be able to kindly guide me to successfully install the ROOT with Python3 support? That would be really helpful for me. Let me know if I need to provide any additional info.

Thanks a lot.

With regards,
Saumyen

[eguiraud]

Hello @Saumyenk ,

in the first screenshot it looks like ROOT is simply not available in the environment. Maybe you didn’t run source /path/to/root/bin/thisroot.sh before starting the python interpreter?

You probably don’t have to build ROOT from source, see if there is a package that works for you at Installing ROOT - ROOT . If not, please review the instructions at Building ROOT from source - ROOT carefully.

About the second error, with the conda environment, it looks like you have a ROOT installation at system level that is interfering with the ROOT installation in the conda environment (note how the error messages refer to /usr/local/lib/libRIO.so while from the conda environment you should be picking up the ROOT that resides in the conda prefix).
Removing the system installation should fix this.

Cheers,
Enrico