# What’s New in 0.13.1¶

## Summary¶

This release of OpenMC includes many bug fixes as well as improvements in geometry modeling, mesh functionality, source specification, depletion capabilities, and other general enhancements. The depletion module features a new transport operator, openmc.deplete.IndependentOperator, that allows a depletion calculation to be performed using arbitrary one-group cross sections (e.g., generated by an external solver) along with a openmc.deplete.MicroXS class for managing one-group cross sections. The track file generation capability has been significantly overhauled and a new openmc.Tracks class was introduced to allow access to information in track files from the Python API. Support has been added for new ENDF thermal scattering evaluations that use mixed coherent/incoherent elastic scattering.

## Compatibility Notes and Deprecations¶

• The openmc.deplete.Operator class has been renamed openmc.deplete.CoupledOperator.

• The openmc.deplete.ResultsList class has been renamed to openmc.deplete.Results and no longer requires you to call the from_hdf5() method in order to create it; instead, you can directly instantiate it.

• A few methods that represent k-effective have been renamed for the sake of consistency:

• The openmc.stats.SphericalIndependent class, which used to accept a distribution for theta now accepts a distribution for cos_theta instead in order to more easily handle the common case of specifying a uniform spatial distribution over a sphere (also see the new openmc.stats.spherical_uniform() function).

• If you are building OpenMC from source, note that several of our CMake options have been changed:

Old option

New option

debug

optimize

profile

OPENMC_ENABLE_PROFILE

coverage

OPENMC_ENABLE_COVERAGE

openmp

OPENMC_USE_OPENMP

OPENMC_USE_MPI

dagmc

OPENMC_USE_DAGMC

libmesh

OPENMC_USE_LIBMESH

The debug and optimize options have been removed; instead, use the standard CMAKE_BUILD_TYPE variable.