:orphan:

behavior_cost
*************

Specifies the cost for behaviors, used in the updating of v- and w-values.
See :ref:`the-mechanisms`.

The parameter ``behavior_cost`` can be set to certain values for certain particular behaviors.
It can also be specified as a single value, in which case the same cost is used for all
behaviors. Wildcards (*) may be used to set several values at once.

Syntax
------

::

  behavior_cost = e1: v1, e2: v2, ..., en: vn, default: d
  behavior_cost = v1
  behavior_cost = *:v1  # Same as above

where ``v1,v2,...,vn`` and ``d`` are :ref:`scalar expressions<scalar-expressions>`.

Description
-----------

``behavior_cost = b1: v1, b2: v2, ..., bn->vn: vn, default: d`` sets the behavior cost for

- b1 to v1,
- b2 to v2, ...,
- bn to vn,

and the behavior cost for all other behaviors to d.

- The specification is independent of the list order:

  ``behavior_cost = b1:v1, b2:v2, default:d``

  is the same as

  ``behavior_cost = b2:v2, default:d, b1:v1``.

- ``default`` need not be specified if all behaviors are present in the list. For example,

  ::

    behaviors = b1, b2
    behavior_cost = b1:v1, b2:v2

----

``behavior_cost = v1`` sets the behavior cost for all behaviors to v1.

- ``behavior_cost = v1`` is the same as ``behavior_cost = default: v1``.

Dependencies
------------

- The property ``behaviors`` must be specified before ``behavior_cost``.
- Each behavior used in the specification of ``behavior_cost`` must be present in the parameter ``behavior_cost``.

Examples
--------

::

  @variables x = 1
  behavior_cost = behavior1: x, behavior2: x+1, behavior3:x+2

sets the behavior cost for behavior1 to 1 and for behavior2 to 2, and
for the remaining behaviors to 3.

::

  behavior_cost = behavior1: 0.5, default:0

sets the behavior cost for behavior1 to 0.5, and for the remaining behaviors to 3.

::

  behavior_cost = 0.1

sets the behavior cost for all behaviors to 0.1.