Installing ROOT via Anaconda

Currently the following ROOT binaries with Python support are provided for the following versions in the main channel:

ROOT ROOT
Python 2.7 / 5.34.32 3.4 / 5.34.32
Python 2.7 / 6.04 3.4 / 6.04

To install ROOT in your conda environment, decide upon the ROOT and Python version you plan to use. We discourage installing everything in your default conda (root) environment, and rather creating a separate one. For example:

$ conda create --name=testenv root=6 python=3
$ source activate testenv

This will install ROOT6 and Python3 and all dependencies to make things work.

Test if ROOT works like it should:

$ root -b -q
   ------------------------------------------------------------
  | Welcome to ROOT 6.05/02                http://root.cern.ch |
  |                               (c) 1995-2014, The ROOT Team |
  | Built for linuxx8664gcc                                    |
  | From tag v6-05-02, 14 September 2015                       |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q' |
   ------------------------------------------------------------

root [0]
$ python
Python 3.4.3 |Continuum Analytics, Inc.| (default, Oct 19 2015, 21:52:17) 
Type "help", "copyright", "credits" or "license" for more information.
Anaconda is brought to you by Continuum Analytics.
>>> import ROOT
>>> f = ROOT.TFile.Open("test.root","recreate")

If you have other channels in your conda configuration (besides the defaults one), make sure that the following packages are picked up from the right one (NLeSC) when you create the new environment.

You may need to set:

$ conda config --set show_channel_urls yes

in order to see the channels from which the binaries are installed.

....
    fftw:       3.3.4-0                https://conda.anaconda.org/NLeSC/linux-64/
    gmp:        5.1.2-2                https://conda.anaconda.org/NLeSC/linux-64/
    graphviz:   2.38.0-3               https://conda.anaconda.org/NLeSC/linux-64/
    gsl:        1.16-1                 https://conda.anaconda.org/NLeSC/linux-64/
    isl:        0.12.2-0               https://conda.anaconda.org/NLeSC/linux-64/
    mpc:        1.0.1-0                https://conda.anaconda.org/NLeSC/linux-64/
    mpfr:       3.1.2-0                https://conda.anaconda.org/NLeSC/linux-64/
    ncurses:    5.9-5                  https://conda.anaconda.org/NLeSC/linux-64/
    pcre:       8.35-0                 https://conda.anaconda.org/NLeSC/linux-64/
    gcc:        4.8.2-20               https://conda.anaconda.org/NLeSC/linux-64/
    readline:   6.2.5-11               https://conda.anaconda.org/NLeSC/linux-64/
....

Downgrading ROOT

If for any reason you want to downgrade ROOT (or any other package) in your environment, simply issue the following from your active environment:

$ conda install ROOT={lower-version}

This will inform you of the new package plan for installation, i.e., pick-up the correct dependencies:

Fetching package metadata: ............
Solving package specifications: ......................
Package plan for installation in environment /home/daniela/anaconda/envs/pax_root_jelle:
[...]
 The following packages will be DOWNGRADED:

    root:       6.04-py3.4_gcc4.8.2 https://conda.binstar.org/NLeSC/linux-64/ --> 5.34.32-py3.4_gcc4.8.2 https://conda.binstar.org/NLeSC/linux-64/

Proceed ([y]/n)? n