Default c++ Notebooks with Root

The following page describes how to setup root with jupyter notebooks such that the default type of a cell is c++. This is what we did above. But you loose the flexibility of mixing python and c++. The description is a bit outdated and repeats what we habe descripted in P1.0 but it referes to another setup with jupterlab-desktop which is no longer maintained.

# Using C++ in Jupyterlab install root from root cern. https://root.cern/install/all_releases/ In the following I assume that root installs into: C:\root_v6.30.04 you might have to replace it accordingly. add the folder C:\root_v6.30.04\bin to your system path variable: https://learn.microsoft.com/en-us/previous-versions/office/developer/sharepoint-2010/ee537574(v=office.14) get python interpreter path inside python with: ```python import sys print(sys.execuble) ``) first edit C:\root_v6.30.04\etc\notebook\kernels\root\kernel.json replace the version according to your installation! ```json { "language": "c++", "display_name": "ROOT C++", "argv": [ "C:\\Users\\admin\\AppData\\Roaming\\jupyterlab-desktop\\jlab_server\\python.exe", "-m", "JupyROOT.kernel.rootkernel", "-f", "{connection_file}" ], "env": { "CD": "c:\\root_v6.30.04\\bin", "PYTHONPATH": "c:\\root_v6.30.04\\bin" } } ``` open in jupyterlab the folder pane and select the + button and open a terminal there type: ``` jupyter kernelspec install C:\root_v6.30.04\etc\notebook\kernels\root\ pip install metakernel ``` if you want to use the webbrowser then do: ``` pip install noteook root --notebookk ``` try commands from https://root.cern.ch/notebooks/HowTos/HowTo_ROOT-Notebooks.html but I set default to c++, so you need to use %%python when you do python code.``

cout <<"Hello Bo";

Hello Bo

%jsroot on

%%python
import ROOT

%%python
h = ROOT.TH1F("gauss","Example histogram",100,-4,4)
h.FillRandom("gaus")

%%python
c = ROOT.TCanvas("myCanvasName","The Canvas Title",800,600)
h.Draw()

%%python
c.Draw()

cout <<"Somehow you need to call C++ to get the graph";

Somehow you need to call C++ to get the graph

    gauss->Fit("gaus", "S");
    myCanvasName->Draw();

****************************************
Minimizer is Minuit2 / Migrad
Chi2                      =      65.0502
NDf                       =           82
Edm                       =  4.61536e-07
NCalls                    =           53
Constant                  =      157.425   +/-   2.76819     
Mean                      =    0.0138321   +/-   0.0143799   
Sigma                     =      1.00178   +/-   0.0104857    	 (limited)