.. _label_init_model_fields:

Initialize Model Fields
========================

  * `initfields` (json object) - Describes how to initialize fields within model. Options:

    * `file` (string) - Initialize fields by reading from filename
    * `field_type` (string) - types of fields to read from the file, `species` or `exchange`

    * `<field_name>` (json object) - This is the name of the field that you want to initialze. For example, this can be `mu_minus` or `mu_plus` to initialize an exchange field or `mu_A` or `mu_B` to initialize species fields. The names of the species fields are based on the label of the `Species`, while the names of the exchange field depend on the model being used. If this is confusing, just to take a look at the examples below. Options:

      * `type` (string) - Initialization type. Options: 

        * `gaussians` - Initialize fields using Gaussins
        * `random` - Initialize fields randomly


Example: Initialize fields `mu_minus` and `mu_plus` using gaussians and from random, respectively. 

.. note::

  Note that the field names must match the model used. E.g. `mu_minus` and `mu_plus` should be used for `MeltChiAB`, but `mu_1` and `mu_+` would be used for `MeltMeltChiMultiSpecies` with incompressibility

(python)::

  fts.model(type='MeltChiAB', ...)
  fts.init_model_field(height=1.0,ngaussian=1,type='gaussians',width=0.1,centers=[0],fieldname='mu_minus')
  fts.init_model_field(type='random',mean=0.0,stdev=1.0,fieldname='mu_plus')



json::

  "model": {
    "type": "MeltChiAB"
    ...
    "initfields": {
      "mu_minus": {
        "center0": [ 0,0 ],
        "center1": [ 0.5,0.5 ],
        "height": 1.0,
        "ngaussian": 2,
        "type": "gaussians",
        "width": 0.1
      },
      "mu_plus": {
        "type": "random",
        "mean": 0.0,
        "stdev": 1.0
      }
      ...
  },



Example: Initialize from file

python ::
  
  import openfts
  fts = openfts.OpenFTS()
  ... 
  field_filename="exchange_fields.in"
  fts.init_fields_from_file(filename=field_filename,field_type='exchange')
  ...

json ::

  "model": {
    "type": ...
    ...
    "initfields": {
      "field_type": "exchange",
      "file":"exchange_fields.in"
    },
    ...
  },