Comment (by Roland Haas):

I looked a bit into what needs to be present. At least for my OSX+Homebrew test system I needed:

• brew install jupyter
• pip3 install sympy
• sys.path.append(“/User/jenkins/Library/Python/3.8/lib/python/site-packages“) otherwise it would not find the package in jupyter notebooks (but would find in python scripts, very odd)
• no other Python package seems required

Python3.8 produced 2 syntax warnings of type ‘SyntaxWarning: "is" with a literatl. Did you mean "=="?’ in mpmath, one of them line 892. Probably not much that can be done about this though.

The example notebook explicitly provides digits for the Euler-gamma constant. However sympy provides this as a symbol already sympy.S.EuerlGamma which probably could (and should) be used instead in the PN expressions (and Float(sympy.S.EuerlGamma) does give the correct digits).

None of the Python functions seem to have a Python docstring, making eg help(pt.f_p_t) not very useful.

NRPyPN_shortcuts.py is really used as some sort of include file injection a number of symbols (among them chi1U etc.) into the main namespace via from NRPyPN_shortcuts import * which is somewhat confusing.

The pt module seems to have some internal state that is manipulated via things like pt.f_p_t. It would seem cleaner if instead there was a pt object that one created instead.

‌

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2417/include-pn-expressions-for-initial-momenta