.. image:: n.128/images/vacancy_diffusion.0.png
           :width: 25%

        .. image:: n.128/images/vacancy_diffusion.10.png
           :width: 25%

        .. image:: n.128/images/vacancy_diffusion.63.png
           :width: 25%

        .. image:: n.128/images/vacancy_diffusion.66.png
           :width: 25%

        .. image:: n.128/images/vacancy_diffusion.200.png
           :width: 25%

        .. image:: n.128/images/vacancy_diffusion.label.png
           :width: 25%

Commands & Concepts
+++++++++++++++++++
* Create lattice [#lattice.source]_
  
  * `dimension`_ (1D|2D|3D), `lattice`_ (FCC,BCC,...), `region`_ (nx,ny,nz)

* Initialize *spin* values
  
  * `set`_ (initialize sites to *1*)
  * `set`_ (set fraction of sites to *2*)

* Select app style: `diffusion`_ (a model for vacancy diffusion)
* Select solve style: `tree`_ (stores event probabilities in binary tree)
* Set *kT*: `temperature`_/energy relevant to *diffusion* model
* Request output text/images for analysis

  * `dump text`_ and/or `dump image`_

* Choose diag style

  * `energy`_ (running energy tally for entire lattice)


*spparks* input file
....................

* Run *spparks*::

   # SPPARKS 'diffusion' model for modeling vacancy diffusion
   # let N=128
   # Simulation temperature
   # kT="1.0"
   # Volume fraction of voids
   # F="0.1"
   spk_flame.gnu -var kT $kT -var N $N  -var F $F < vacancy_diffusion.in

* :download:`Download 'vacancy_diffusion.in'  <n.128/vacancy_diffusion.in>`

  .. literalinclude:: n.128/vacancy_diffusion.in
     :language: bash

----

.. [#lattice.source] 
        .. image:: ../grain_growth/images/cubic_lattice_bcc.gif

        https://www.uwgb.edu/dutchs/symmetry/bravais.htm

.. _dimension: http://spparks.sandia.gov/doc/dimension.html
.. _lattice: http://spparks.sandia.gov/doc/lattice.html
.. _region: http://spparks.sandia.gov/doc/region.html
.. _set: http://spparks.sandia.gov/doc/set.html
.. _read sites: http://spparks.sandia.gov/doc/read_sites.html
.. _diffusion: http://spparks.sandia.gov/doc/app_diffusion.html
.. _tree: http://spparks.sandia.gov/doc/solve_style.html
.. _temperature: http://spparks.sandia.gov/doc/temperature.html
.. _dump text: http://spparks.sandia.gov/doc/dump.html
.. _dump image: http://spparks.sandia.gov/doc/dump_image.html
.. _cluster: http://spparks.sandia.gov/doc/diag_cluster.html
.. _energy: http://spparks.sandia.gov/doc/diag_energy.html