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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*.