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Sassena
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Sassena is a highly scalable parallelized software for calculating neutron and
X-ray scattering patterns from all-atomic molecular dynamics simulations.
It supports distributed-memory parallelism via MPI and shared-memory parallelism
via OpenMP, making it suitable for modern HPC environments.

The direct computation of scattering patterns based on (all-atomic) molecular
dynamics trajectories allows reconciliation of simulations with experiment.
Scattering patterns also provide a powerful tool to investigate structural and
dynamical properties of simulated molecular systems by reducing the amount of
information into meaningful structural and dynamical fingerprints.

Sassena computes the scattering patterns very quickly and offers the capabilities 
to use high-performance computing facilities. It uses `pdb` and `dcd` files as
MD trajectory input.

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   :maxdepth: 2
   :caption: Contents

   tutorials/index
   how-to/index
   explanation/index
   reference/index
   development/index
   api/index
   
There are alternative programs that compute similar quantities, notably also

* `MDANSE <https://mdanse.readthedocs.io/>`__ written in Python with a GUI
* `LiquidLib <https://z-laboratory.github.io/LiquidLib/>`__ for orientation-averaged
  quantities

Sassena is a command-line tool that concentrates on calculating neutron and X-ray 
scattering functions. It can compute the quantities in different directions of 
reciprocal space and perform numerical averages over these.

If you use Sassena for your calculations please cite the following reference:

   B. Lindner and J.C. Smith, 2012, "Sassena — X-ray and neutron scattering
   calculated from molecular dynamics trajectories using massively parallel
   computers", Comp. Phys. Comm., Volume 183, Issue 7, Pages 1491–1501, 
   http://dx.doi.org/10.1016/j.cpc.2012.02.010