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% If you are using CVS use this line to give version information
% $Header$

\documentclass{article}

% Use the Cactus ThornGuide style file
% (Automatically used from Cactus distribution, if you have a
%  thorn without the Cactus Flesh download this from the Cactus
%  homepage at www.cactuscode.org)
\usepackage{../../../../doc/latex/cactus}

\begin{document}

% The author of the documentation
\author{Zachariah B.~Etienne \textless zachetie *at* gmail *dot* com\textgreater}

% The title of the document (not necessarily the name of the Thorn)
\title{\texttt{NRPyPN}: Validated Post-Newtonian Expressions for Input
  into Wolfram Mathematica, SymPy, or Highly-Optimized C Codes. Also
  provides low-eccentricity binary black hole initial data parameters
  for Bowen-York initial data (e.g., TwoPunctures)}

% the date your document was last changed, if your document is in CVS,
% please use:
%    \date{$ $Date$ $}
\date{December 22, 2020}

\maketitle

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% START CACTUS THORNGUIDE

% Add all definitions used in this documentation here
%   \def\mydef etc

% Add an abstract for this thorn's documentation
Post-Newtonian theory results in some of the longest and most complex
mathematical expressions ever derived by humanity.

These expressions form the core of most gravitational wave data
analysis codes, as well as codes used to construct low-eccentricity
initial data for numerical relativity simulations of compact binary
systems (e.g., using \texttt{TwoPunctures}), but generally the
expressions are written in a format 
that is either inaccessible by others (i.e., closed-source) or written
directly in e.g., C code and thus incompatible with symbolic algebra
packages like Wolfram Mathematica or the
Python-based SymPy.

Once in a symbolic algebra package, these expressions could be
manipulated, extended, and output as {\it more} optimized C codes
(e.g., using SymPy/NRPy+, thus speeding up gravitational wave data
analysis and making it easier to quickly get needed low-eccentricity
parameters for setting up binary black hole initial data).

NRPyPN aims to provide a trusted source for validated
Post-Newtonian expressions useful for gravitational wave astronomy,
using the open-source SymPy computer algebra
system, so that expressions can be output into Wolfram
Mathematica or highly optimized C codes using the SymPy-based
\texttt{NRPy+}.

In particular, \texttt{NRPyPN} exists within the \texttt{Einstein
  Toolkit} to provide a convenient interface for computing
parameters for low-eccentricity binary black hole initial data, as
computed by the \texttt{TwoPunctures} thorn. The interface for
accomplishing this is provided by at the bottom of the
well-documented, interactive Jupyter notebook located at
\texttt{NRPyPN.ipynb} in the Einstein Toolkit. Instructions for
getting the Jupyter notebook up and running are provided in the
\texttt{README} file.

If you do not have Jupyter installed the online version
at~\cite{EinsteinInitialData_NRPyPN_MyBinder} may be used instead.

\begin{thebibliography}{9}

\bibitem{EinsteinInitialData_NRPyPN_MyBinder}
MyBinder online NRPyPN notebook,
\url{https://mybinder.org/v2/gh/zachetienne/nrpytutorial/master?filepath=NRPyPN%2FNRPyPN.ipynb}.

\end{thebibliography}


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\end{document}
