NCrystal release 4.3.0

[tkittel]

NCrystal 4.3.0 : The MiniMC utility grows up

The NCrystal developers are proud to present a release in which the built-in "MiniMC" framework, is finally growing up. This framework allows doing simple simulations in which neutrons are propagated through a single convex volume and recorded as they come out. Although a small "toy" preview of the MiniMC framework was available in NCrystal since release 3.9.0, it is now much more feature complete and (hopefully) useful for a much wider range of use-cases. The MiniMC is included with NCrystal itself, and is intended to be accessed from either Python or via the new command-line tool ncrystal_minimc. It is intended as a light-weight alternative to using NCrystal in fully-fledged applications like McStas/OpenMC/..., and can be used to investigate properties of neutrons scattered in a particular material, including the effects of geometry and multiple scattering.

Here is an example of how to use the MiniMC in a Jupyter notebook:

Some MiniMC highlights

• Shapes available: box, sphere, cylinder, infinite slab, infinite cylinder.
• Sources geometries available: pencil beam, circular beam, isotropic.
• Source energy distributions available (in ekin or wavelength): Fixed, log-normal, uniform range, thermal (Maxwell).
• Pre-defined tally histograms: energy, q, wavelength, scatter angle, energy loss, scattering order, ...
• Flexible tallying via user (Numpy) code supported.
• JSON persistification supported.
• Focus on speed, typically filling tally histograms at above >10MHz. Relies on highly vectorized code and multithreading.

For more information about the MiniMC, please refer to the documentation in the wiki.

Other things in the release

In addition to the MiniMC, the release contains a slew of other updates and features. A few of the more noteworthy are listed here:

• A general speed-up of NCrystal processes related to cross section calculation and sampling of final state.
• All obsolete functions in the C API now emits a warning message if called.
• Introduction of a new command-line tool named just ncrystal, which can be used to access the full suite of command-line tools (i.e. run ncrystal cif2ncmat <args> instead of ncrystal_cif2ncmat <args>.
• NCrystal code will no longer build on 32bit systems.
• Under the hood we have added a new "JSON query" mechanism to NCrystal, which is intended to make it a lot easier for NCrystal developers to export data available in the C++ layer to the Python or command-line APIs. This does not bring any user-visible features at this moment.

For the full details of what was changed in the release, refer to the CHANGELOG file or the Full diff: v4.2.12...v4.3.0