Package groupthink :: Module aatree :: Class SumWalker

Class SumWalker

Walker --+
         |
        SumWalker

SumWalker is designed to walk over full trees where each leaf has annotation 1 and the monoid is +. Target is the zero-indexed position of the target node.

There is one exception: the last node in every tree has annotation 0.

Instance Methods

[hide private]

prepare_descend(self, target)
An optional method to prepare for descent

source code

int

descend(self, node)
Returns: descend must return 0 if the node in question is the one desired, -1 if the left child would be better, or 1 if the right child would be better.

source code

prepare_ascend(self)
An optional method to prepare for ascent

source code

bool

ascend(self, node)
Returns: ascend should return True iff it should run again on the parent of node.

source code

Class Variables

[hide private]

target = None

offset = None

Method Details

[hide private]

prepare_descend(self, target)

source code

An optional method to prepare for descent

Overrides: Walker.prepare_descend: (inherited documentation)

descend(self, node)

source code

Parameters:

node - A node from which to descend.

Returns: int

descend must return 0 if the node in question is the one desired, -1 if the left child would be better, or 1 if the right child would be better.

Overrides: Walker.descend

(inherited documentation)

prepare_ascend(self)

source code

An optional method to prepare for ascent

Overrides: Walker.prepare_ascend: (inherited documentation)

ascend(self, node)

source code

Parameters:

node - A node from which to ascend

Returns: bool

ascend should return True iff it should run again on the parent of node. It should set the walker's internal state such that a subsequent descent would retrace these steps.

Overrides: Walker.ascend

(inherited documentation)