Operator
========

.. autoclass:: openfts.operator.Hamiltonian
    :members:

.. autoclass:: openfts.operator.CellStress
    :members:

.. autoclass:: openfts.operator.ChemicalPotential
    :members:

.. autoclass:: openfts.operator.Pressure
    :members:

.. autoclass:: openfts.operator.PressureUVSensitive
    :members:

.. autoclass:: openfts.operator.DensityMolecule
    :members:

.. autoclass:: openfts.operator.DensitySpecies
    :members:

.. autoclass:: openfts.operator.DensityModelCustom
    :members:

.. autoclass:: openfts.operator.SpeciesFields
    :members:

Block Averaging
----------------
Block averaging (i.e. `block_size`) and the output frequency (i.e. `output_freq`) are handled independently within the code. Block averaging reports operators that are averaged over `block_size` sequential timesteps. The current value of operators are written to `operators.dat` and `op*.dat` files every `output_freq` steps. 

To see the expected results of block averaging, consider a timeseries of a given operator that takes the values d1 to d8 on 8 sequential timesteps t1 to d8:

.. table:: 

  ==========  ==== ==== ==== ====  ==== ==== ==== ====
  timestep     t1   t2   t3   t4    t5   t6   t7   t8
  ==========  ==== ==== ==== ====  ==== ==== ==== ====
  value        d1   d2   d3   d4    d5   d6   d7   d8
  ==========  ==== ==== ==== ====  ==== ==== ==== ====


If `block_size = 2` and `output_freq=1` then the output to `operators.dat` will be

.. table:: 

  ==========  ==== =========== ==== ===========  ==== =========== ==== ===========
  timestep     t1   t2          t3       t4       t5       t6      t7       t8
  ==========  ==== =========== ==== ===========  ==== =========== ==== ===========
  value        d1   (d1+d2)/2   d3   (d3+d4)/2    d5   (d5+d6)/2   d7   (d7+d8)/2
  ==========  ==== =========== ==== ===========  ==== =========== ==== ===========

If `block_size = 1` and `output_freq=2` then the output to `operators.dat` will be

.. table:: 

  ========== ==== ==== ==== ====
  timestep    t2   t4   t6   t8 
  ========== ==== ==== ==== ====
  value       d2   d4   d6   d8 
  ========== ==== ==== ==== ====


If `block_size = 2` and `output_freq=2` then the output to `operators.dat` will be

.. table::

  ==========   ===========  ===========  =========== ===========
  timestep      t2               t4           t6          t8
  ==========   ===========  ===========  =========== ===========
  value         (d1+d2)/2    (d3+d4)/2    (d5+d6)/2   (d7+d8)/2
  ==========   ===========  ===========  =========== ===========