InitField
=========

It is possible to initialize either the **exchange fields** or **species fields** within a model.


Initializing exchange fields
------------------------------

When initializing exchange fields, the names of the fields will depend on the Model you are using. For example, for ModelChiAB: ::

    fts.model = openfts.model.ChiAB( ...)

    # exchange fields
    fts.model.init_fields['mu_minus'] = openfts.init_field.Random(mean=0.0,stdev=1.0)
    fts.model.init_fields['mu_plus'] = openfts.init_field.Random(mean=0.0,stdev=1.0)

Or for ModelChiMultiSpecies: ::

    fts.model = openfts.model.ChiMultiSpecies( ...)

    # exchange fields
    fts.model.init_fields['mu_1'] = openfts.init_field.Random(mean=0.0,stdev=1.0)
    fts.model.init_fields['mu_2'] = openfts.init_field.Random(mean=0.0,stdev=1.0)
    fts.model.init_fields['mu_3'] = openfts.init_field.Random(mean=0.0,stdev=1.0)

.. note::

    If you are having trouble determining the names of the exchange fields for your current model, try removing the `fts.model.init_fields` lines from your input file and run OpenFTS. The names of the exchange fields for your current model will be output to the log.

Initializing species fields
------------------------------

It is generally conceptually more clear to initialize the species fields of the model. . One advantage of this approach is that this initialization will be independent of Model. Another advantage is that the species fields are generally easier to understand physically: the density of a species will be large where the species field is low. To initialize the using a species field, you will specify the name of the field that is consistent with that species' label specified by `Species(label='A')`. For example::

      # species fields
      fts.species.append(openfts.Species(label='A', ...))
      fts.species.append(openfts.Species(label='B', ...))
      fts.model.init_fields['mu_A'] = ... # 'mu_A' is consistent with Species(label='A') above
      fts.model.init_fields['mu_B'] = ... # 'mu_B' is consistent with Species(label='B') above


Ways to initialize exchange/species fields
-------------------------------------------

.. autoclass:: openfts.init_field.Gaussian
    :members:

.. autoclass:: openfts.init_field.Random
    :members:

.. autoclass:: openfts.init_field.FromFile
    :members: