graphi.operators.interface module

graphi.operators.interface.graph_operator(prefix='graphi')

Implement a callable as a graph operator

Parameters:prefix – identifier to prepend to special method names

Adds the operator lookup and fallback procedure to allow Graph subclasses to implement optimized algorithms. For example, a graph storing edges in a sorted data structure may prematurely end a search for neighbours given a maximum distance.

A graph can influence the evaluation of a graph operator by providing an attribute named __<prefix>_<operator name>__, e.g. __graphi_neighbours__ for an operator neighbours. If this is the case, the attribute is called with the provided arguments as a replacement for the operator implementation.

graphi.operators.interface.operator(graph, *args, **kwargs)

The generic implementation of a graph operator.

graph.__graphi_operator__(*args, **kwargs)

The optimized implementation of a graph operator.

There are three special conditions to this procedure:

attribute is None

The graph does not support the operation.

Attempting the operation on the graph raises TypeError.

attribute is NotImplemented

The graph does not overwrite the operation. The operator implementation is always used.

calling the attribute returns NotImplemented

The graph does not overwrite the operation for the specific parameters. The operator implementation is used.

The name of an operator is taken from operator.__name__ or operator.__class__.__name__.