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- :mod:`altgraph.GraphUtil` --- Utility functions
- ================================================
- .. module:: altgraph.GraphUtil
- :synopsis: Utility functions
- The module :mod:`altgraph.GraphUtil` performs a number of more
- or less useful utility functions.
- .. function:: generate_random_graph(node_num, edge_num[, self_loops[, multi_edges])
- Generates and returns a :class:`Graph <altgraph.Graph.Graph>` instance
- with *node_num* nodes randomly connected by *edge_num* edges.
- When *self_loops* is present and True there can be edges that point from
- a node to itself.
- When *multi_edge* is present and True there can be duplicate edges.
- This method raises :class:`GraphError <altgraph.GraphError` when
- a graph with the requested configuration cannot be created.
- .. function:: generate_scale_free_graph(steps, growth_num[, self_loops[, multi_edges]])
- Generates and returns a :py:class:`~altgraph.Graph.Graph` instance that
- will have *steps*growth_n um* nodes and a scale free (powerlaw)
- connectivity.
-
- Starting with a fully connected graph with *growth_num* nodes
- at every step *growth_num* nodes are added to the graph and are connected
- to existing nodes with a probability proportional to the degree of these
- existing nodes.
- .. warning:: The current implementation is basically untested, although
- code inspection seems to indicate an implementation that is consistent
- with the description at
- `Wolfram MathWorld <http://mathworld.wolfram.com/Scale-FreeNetwork.html>`_
- .. function:: filter_stack(graph, head, filters)
- Perform a depth-first oder walk of the graph starting at *head* and
- apply all filter functions in *filters* on the node data of the nodes
- found.
- Returns (*visited*, *removes*, *orphans*), where
- * *visited*: the set of visited nodes
- * *removes*: the list of nodes where the node data doesn't match
- all *filters*.
- * *orphans*: list of tuples (*last_good*, *node*), where
- node is not in *removes* and one of the nodes that is connected
- by an incoming edge is in *removes*. *Last_good* is the
- closest upstream node that is not in *removes*.
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