On my iMac (Yosemite), I went through the explanations on the github wiki, and when starting ipython I got an error "No module named notebook.notebookapp
". Goggled and landed on SO at http://stackoverflow.com/questions/31397421/ipython-server-cant-launch-no-module-named-notebook-notebookapp and then ran "pip install jupyter" as advised. I then got " No module named functools32". I could finally start ipython after also running "pip install functools32".
From Valentin