PyNE 0.1 Release Notes

PyNE 0.1 is the first release of Python for Nuclear Engineering project after an initial year of effort. PyNE is a free and open source (BSD licensed) project which is meant to compliment other projects, such as NumPy and SciPy, as a necessary package in the computational nuclear engineer’s toolkit. It is meant to play nicely with existing, industry standard nuclear engineering tools. The goal of PyNE is to be both fast and useful. As such, this is only the beginning!

Release highlights:

  • Support for many I/O routines.
  • Nuclear data interface.
  • C/C++ library which may be linked against independent of Python.
  • Cython wrappers for C++ standard library containers.

Please visit our website for more information:

PyNE requires Python 2.7, NumPy 1.5+, PyTables 2.1+.

New features

Nuclide Naming in pyne.nucname

This module may be used to convert between various nuclide naming schemes. Currently the following naming conventions are supported: zzaaam, human readable names, MCNP, Serpent, NIST, and CINDER. This module is implemented in C.

Basic Nuclear Data via

This aims to provide quick access to very high fidelity nuclear data. Usually values are taken from the nuc_data.h5 library which is generated with the new nuc_data_make utility at install. Current data includes atomic masses, decay data, neutron scattering lengths, and simple cross section data. 63-group neutron cross sections, photon cross sections, and fission product yields are also added when CINDER is available. This module is implemented in C.

Material Class in pyne.material

Materials are the primary container for radionuclides throughout PyNE. They map nuclides to mass weights, though they contain methods for converting to/from atom fractions as well. In many ways they take inspiration from numpy arrays and python dictionaries. Materials are implemented in C++ and support both text and HDF5 I/O.

CCCC Formats in pyne.cccc

The CCCC module contains a number of classes for reading various cross section, flux, geometry, and data files with specifications given by the Committee for Computer Code Coordination. The following types of files can be read using classes from this module: ISOTXS, DLAYXS, BRKOXS, RTFLUX, ATFLUX, RZFLUX, MATXS, and SPECTR.

ACE Cross Sections in pyne.ace

This module is for reading ACE-format cross sections. ACE stands for “A Compact ENDF” format and originated from work on MCNP. It is used in a number of other Monte Carlo particle transport codes.

Cross Section Interface via pyne.xs

This is a top-level interface for computing (and caching) multigroup neutron cross sections. These cross sections will be computed from a variety of available data sources (stored in nuc_data.h5). In order of preference:

  1. CINDER 63-group cross sections,
  2. A two-point fast/thermal interpolation (using ‘simple_xs’ data from KAERI),
  3. or physical models implemented in this sub-package.

In the future, this package will support generating multigroup cross sections from user-specified pointwise data sources (such as ENDF or ACE files).

ORIGEN 2.2 Support in pyne.origen22

This provides an interface for reading, writing, and merging certain ORIGEN 2.2 input and output files. Specifically, tapes 4, 5, 6, and 9 are supported.

Serpent Support in pyne.serpent

Serpent is a continuous energy Monte Carlo reactor physics code. Pyne contains support for reading in Serpent’s three types of output files: res, dep, and det. These are all in Matlab’s *.m format and are read in as Python dictionaries of numpy arrays and Materials. They may be optionally written out to corresponding *.py files and imported later.

C++ Standard Library Converters in pyne.stlconverters

This module contains wrapper classes for commonly used containers in the C++ standard library. This module is largely used by PyNE under the covers, in Cython and elsewhere. However, these classes are of more general interest so feel free to use them in your own code as well. Currently implemented are SetInt, SetStr, MapStrInt, MapIntStr, MapIntDouble, and MapIntComplex.

Nuclear Data Generation in pyne.dbgen

Pyne provides an easy-to-use, repeatable aggregation utility for nuclear data. This command line utility is called nuc_data_make builds and installs an HDF5 file named nuc_data.h5 to the current PyNE install. Nuclear data is gathered from a variety of sources, including the web and the data files for other programs installed on your system (such as MCNP).


This release contains code written by the following people (in alphabetical order):

  • Christopher Dembia
  • Robert Flanagan
  • Paul Romano
  • Anthony Scopatz
  • Paul Wilson

Additionally, we would like to thank the following people for their inspiration, guidance, and testing:

  • Katy Huff
  • Seth Johnson
  • Joshua Peterson
  • Rachel Slaybaugh
  • Nick Touran
  • Morgan White