Hands on
++++++++

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

.. image:: n.128/images/grain_growth.3.png
   :width: 25%

.. image:: n.128/images/grain_growth.28.png
   :width: 25%

Try these variations and make simple observations
.................................................
* Run *lattice* :math:`128\times 128,\; kT=1.25`
* Run *lattice* :math:`156\times 156,\; kT=.33`
* Try a different lattice type (`tri`_)
* If you have an *mpi* build of *spparks*

  ::

        mpiexec -np 2 spk_flame.gnu -var kT $kT -var N $N -var Q $Q < grain_growth.in

* What does the *energy* column/tally imply?

  ::

      Time    Naccept    Nreject    Nsweeps        CPU     Energy
         0          0          0          0          0 8.3886e+06
   55.8037    8151847          0         16       5.76 1.22051e+06
   106.508   10436619          0         22       9.23     928128
   150.774   11995846          0         27       14.4     794076
   205.157   13620596          0         33       17.6     689672
   251.346   14834712          0         38         21     624934
       300   15991604          0         44         26     572196


* Change the number of spin values :math:`Q`


.. _tri: http://spparks.sandia.gov/doc/lattice.html