refine_plan.models.behaviour_tree
=================================

.. py:module:: refine_plan.models.behaviour_tree

.. autoapi-nested-parse::

   A very lightweight set of classes for BTs.

   This is effectively a BT data structure which allows us to write out to
   a BT.cpp XML file recursively. I don't want the heavyweight baggage of pytree etc.

   Author: Charlie Street
   Owner: Charlie Street



Classes
-------

.. autoapisummary::

   refine_plan.models.behaviour_tree.BTNode
   refine_plan.models.behaviour_tree.ActionNode
   refine_plan.models.behaviour_tree.ConditionNode
   refine_plan.models.behaviour_tree.CompositeNode
   refine_plan.models.behaviour_tree.SequenceNode
   refine_plan.models.behaviour_tree.FallbackNode
   refine_plan.models.behaviour_tree.BehaviourTree


Module Contents
---------------

.. py:class:: BTNode

   Bases: :py:obj:`object`


   Base class for individual BT nodes.


   .. py:method:: to_BT_XML()
      :abstractmethod:


      Outputs a string containing the BT.cpp XML for this node.

      :returns: The BT XML for this node as a string



.. py:class:: ActionNode(name)

   Bases: :py:obj:`BTNode`


   Node class for BT action nodes.

   .. attribute:: _name

      The name of the action being executed.


   .. py:method:: get_name()

      Getter for self._name.

      :returns: The action name



   .. py:method:: to_BT_XML()

      Generates the BT.cpp XML string for the action node.

      :returns: The BT.cpp XML for the action node



   .. py:method:: tick_at_state(state)

      Computes node return value if ticked in a given state.

      This function ignores any node memory, and should only be used
      to check correspondence with a Markov policy.

      :param state: The state to check

      :returns: The return value of this node being ticked (action name)



.. py:class:: ConditionNode(name, cond)

   Bases: :py:obj:`BTNode`


   Node class for BT condition nodes.

   .. attribute:: _name

      The name of the condition node

   .. attribute:: _cond

      The condition which the node checks


   .. py:method:: get_name()

      Getter for self._name.

      :returns: The condition node name



   .. py:method:: get_cond()

      Getter for self._cond.

      :returns: The condition being checked



   .. py:method:: to_BT_XML()

      Generates the BT.cpp XML string for the condition node.

      :returns: The BT.cpp XML for the condition node



   .. py:method:: tick_at_state(state)

      Computes node return value if ticked in a given state.

      This function ignores any node memory, and should only be used
      to check correspondence with a Markov policy.

      :param state: The state to check

      :returns: The return value of this node being ticked (True or False)



.. py:class:: CompositeNode(*children)

   Bases: :py:obj:`BTNode`


   A class for BT composite nodes (sequence/fallback).

   This class currently represents synchronous composite nodes,
   i.e. composite with memory nodes.

   .. attribute:: _children

      The child nodes


   .. py:method:: add_child(child)

      Add a new child to the composite node.

      :param child: The new child

      :raises invalid_child_exception: Raised if a child is not a BT node



   .. py:method:: to_BT_XML()
      :abstractmethod:


      Generates the BT.cpp XML string for the composite node.

      :returns: The BT.cpp XML string for the composite node



.. py:class:: SequenceNode(*children)

   Bases: :py:obj:`CompositeNode`


   Subclass of CompositeNode for sequence nodes.

   .. attribute:: Same as superclass.

      


   .. py:method:: to_BT_XML()

      Generates the BT.cpp XML string for the sequence node.

      :returns: The BT.cpp XML for the sequence node



   .. py:method:: tick_at_state(state)

      Computes node return value if ticked in a given state.

      This function ignores any node memory, and should only be used
      to check correspondence with a Markov policy.

      :param state: The state to check

      :returns: The return value of this node being ticked



.. py:class:: FallbackNode(*children)

   Bases: :py:obj:`CompositeNode`


   Subclass of CompositeNode for fallback nodes.

   .. attribute:: Same as superclass.

      


   .. py:method:: to_BT_XML()

      Generates the BT.cpp XML string for the fallback node.

      :returns: The BT.cpp XML for the fallback node



   .. py:method:: tick_at_state(state)

      Computes node return value if ticked in a given state.

      This function ignores any node memory, and should only be used
      to check correspondence with a Markov policy.

      This is because it won't work if we have two actions in sequence...
      The convert_policy functionality ensures this will never happen.

      :param state: The state to check

      :returns: The return value of this node being ticked



.. py:class:: BehaviourTree(root_node)

   Bases: :py:obj:`object`


   Class for a complete behaviour tree.

   This class just enforces a root node and adds the outer layers on the
   BT.cpp XML file.

   .. attribute:: _root_node

      A root BTNode


   .. py:method:: get_root_node()

      Getter for self._root_node.

      :returns: The root node of the BT



   .. py:method:: to_BT_XML(out_file=None)

      Produces the BT.cpp XML file for the BT.

      :param out_file: Optional. If specified, will write the BT XML string to file

      :returns: The BT.cpp XML



   .. py:method:: tick_at_state(state)

      Computes node return value if ticked in a given state.

      This function ignores any node memory, and should only be used
      to check correspondence with a Markov policy.

      This is because it won't work if we have two actions in sequence in the fallback.
      The convert_policy functionality ensures this will never happen.

      :param state: The state to check

      :returns: The return value of this node being ticked