Ubuntu – apt-get install vs pip install

Ok, lets follow the installation guide:

1. It says you need python 2.7 (which you already have):

   $ python --version
   Python 2.7.4
   

2. Then it says that you need the numpy package too, version >= 1.4.1:

   apt-cache policy python-numpy
   python-numpy:
   Installed: (none)
   Candidate: 1:1.7.1-1ubuntu1
   Version table:
    1:1.7.1-1ubuntu1 0
       500 http://archive.ubuntu.com/ubuntu/ raring/main amd64 Packages

   As you can see, I have available numpy version 1.7.1, so lets proceed to install it:

   sudo apt-get install python-numpy
   

3. Now it says that we need cython, lets check if that package is availabe:

   apt-cache policy cython
   cython:
   Installed: (none)
   Candidate: 0.17.4-0ubuntu1
   Version table:
    0.17.4-0ubuntu1 0
       500 http://archive.ubuntu.com/ubuntu/ raring/main amd64 Packages

   We have it, we install it:

   sudo apt-get install cython
   

   Please, do notice that there are other packages that are dependency that are being installed too.

4. Oddly enough, we also need the scipy module too:

   sudo apt-get install python-scipy
   

5. Testing. Open python in a terminal and type the following:

   $ python
   Python 2.7.4 (default, Sep 26 2013, 03:20:26) 
   [GCC 4.7.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import numpy
   >>> import scipy
   >>> import cython
   >>> exit()
   

   The above, has to be without errors. If something went wrong, go up and read the guide again, you forgot/skiped a step.

6. Downloading the CLASS sources from their page, go to the directory in the terminal, and untar it and make it:

   cd where/the/tar/is
   tar zxf class_v2.0.2.tar.gz
   cd class_v2.0.2
   make

   Here we will wait until is complete. Once this is done, we go to the python directory and start the magic. Without moving from directories run this:

   cd python
   python setup.py build
   python setup.py install --user

   Now we have CLASS installed in our user directory. We should test it!

   python
   Python 2.7.4 (default, Sep 26 2013, 03:20:26)
   [GCC 4.7.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> from classy import Class
   >>> exit()
   

   Everything is nice a cozzy until here.

7. Now the truth time, download monthypython tarball in your code directory:

   cd ~
   mkdir code
   cd code
   wget https://www.dropbox.com/s/l7mnhwsktp1m8b5/montepython_v1.2.5.tar.bz2?dl=1 -O montepython_v1.2.5.tar.bz2
   tar jxf montepython_v1.2.5.tar.bz2

   In the installation instructions are some notes that aren't relevant in this peculiar case (a new install) but it may be important when you update montepython.

8. This change is important. You remember where you installed CLASS? Now you should tell Monte Python where is that. In my case it is /home/braiam/src/class_v2.0.2/class, yours may be different. You can use find to look for it:

   find ~ -name class -print
   

   Well, now I modify the default.conf file using whatever you like (I'll use nano) and modify the root path, so the complete file will looks like:

   # Fill in the relevant path to your personal distribution. 
   # If you create a new file out of this one, please remember to call
   # MontePython.py with the option '-conf my.conf'
   
   # At minimum, this file should contain one line:
   # ** path['cosmo'] =  path to the cosmological code you are using. Note, if you are
   # using a modified version of class, be sure that the path contains the word
   # class, otherwise the code might not recognise it.
   
   # If you want to use a data folder different from the one present in the folder
   # you are executing the code, please also add:
   # ** path['data']  =  /path/to/the/other/data/
   
   root = '/home/braiam/src/class_v2.0.2/'
   
   path['cosmo']           = root+'/class/'
   

   Save the file and exit.

9. Test montepython! If everything was ok, you should be able to run code/MontePython.py --help in your montepythong directory and everything should run:

   ~/src/montepython$ code/MontePython.py --help
   usage: MontePython.py [-h] [-N number of steps] [-o output folder]
                     [-p input param file] [-c input cov matrix]
                     [-j jumping method] [-f jumping factor]
                     [-conf configuration file] [-chain_number chain number]
                     [-r restart from chain] [-bf restart from best fit file]
                     [-info [compute information of desired file [compute information of desired file ...]]]
                     [-bins desired number of bins, default is 20] [-no_mean]
                     [-comp comparison folder]
                     [-extra plot file for custom needs] [-noplot] [-all]
                     [-ext change extension for the output file]
                     [-fontsize desired fontsize, default is 15]
                     [-ticksize desired ticksize, default is 13]
   
   Monte Python, a Monte Carlo code in Python
   
   
   optional arguments:
   -h, --help            show this help message and exit
   -N number of steps
   -o output folder
   -p input param file
   -c input cov matrix
   -j jumping method
   -f jumping factor
   -conf configuration file
   -chain_number chain number
   -r restart from chain
   -bf restart from best fit file
   -info [compute information of desired file [compute information of desired file ...]]
   -bins desired number of bins, default is 20
   -no_mean
   -comp comparison folder
   -extra plot file for custom needs
   -noplot
   -all
   -ext change extension for the output file
   -fontsize desired fontsize, default is 15
   -ticksize desired ticksize, default is 13

With this, you have montepython installed and ready to roll!

Have you tried to reinstall it? It worked directly for me on one machine and on a VM I had to do a link from ~/anaconda/bin/conda to /usr/local/bin to get it to work. You can do a hardlink with sudo ln ~/anaconda/bin/conda /usr/local/bin/