pynucastro

Python interfaces to the nuclear reaction rate databases, including the JINA Reaclib nuclear reactions database. This project has 2 goals:

• allow for an exploration of rates and collection of rates (networks) in Jupyter notebooks

• allow for the easy creation of the righthand side routines for reaction network integration (the ODEs)

To do this, pynucastro provides a parser for the Reaclib format to produce either a callable python function for a rate or output the python code for a function that can be incorporated into a rate module.

pynucastro does not yet support nuclear partition functions for Reaclib reverse rates, as the implementation is currently under development. We recommend you consider what problem you wish to study using pynucastro to determine whether reverse rates and partition function corrections are significant at the temperatures of interest.

documentation

Documentation for pynucastro is available here:

http://pynucastro.github.io/pynucastro/

example

import pynucastro

r = pynucastro.load_rate("c13-pg-n14-nacr")

# evaluate this rate at T = 1.e9 K
print(r.eval(1.0e9))

An extensive demonstration of the capabilities of pynucastro is shown in this notebook:

pynucastro-examples.ipynb

We can also interactively explore a reaction network. Here's an example of hot-CNO with breakout reactions:

by increasing the temperature, you can see the transition from CNO to hot-CNO (proton captures on C13 become faster than the beta decay) and then the breakout of hot-CNO when the alpha capture on O14 becomes faster than its decay.

install

To install the package, you can run:

python setup.py install

for a systemwide install, or

python setup.py install --user

for a single-user install. This will put the pynucastro modules and library in the default location python searches for packages.

requirements

This package requires Python 3 (release 3.6 or later) and the following Python packages:

• numpy

• sympy

• scipy

• matplotlib

• networkx

• ipywidgets

• numba

• setuptools_scm

To build the documentation or run the unit tests, sphinx and pytest are additionally required along with some supporting packages. See the included requirements.txt file for a list of these packages and versions. To install the packages from the requirements file, do:

pip install -r requirements.txt

Is important to stress out that all the dependencies should be installed before pynucastro, otherwise the installation should be repeated.

unit tests

We use py.test to do unit tests. In pynucastro/, do:

pytest -v .

to see coverage, do:

pytest --cov=pynucastro .

to test the notebooks, do:

py.test --nbval examples

Core Developers

People who make a number of substantive contributions (new features, bug fixes, etc.) will be named "core developers" of pynucastro.

Core developers will be recognized in the following ways:

• invited to the group's slack team

• listed in the User's Guide and website as a core developer

• listed in the author list on the Zenodo DOI for the project (as given in the .zenodo.json file)

• invited to co-author general code papers / proceedings describing pynucastro. (Note: science papers that use pynucastro will always be left to the science paper lead author to determine authorship).

If a core developer is inactive for 3 years, we may reassess their status as a core developer.