import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

python/altgraph/doc/graph.rst

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+:mod:`altgraph.Graph` --- Basic directional graphs
+==================================================
+
+.. module:: altgraph.Graph
+   :synopsis: Basic directional graphs.
+
+The module :mod:`altgraph.Graph` provides a class :class:`Graph` that
+represents a directed graph with *N* nodes and *E* edges.
+
+.. class:: Graph([edges])
+
+  Constructs a new empty :class:`Graph` object. If the optional
+  *edges* parameter is supplied, updates the graph by adding the
+  specified edges.
+
+  All of the elements in *edges* should be tuples with two or three
+  elements. The first two elements of the tuple are the source and
+  destination node of the edge, the optional third element is the
+  edge data.  The source and destination nodes are added to the graph
+  when the aren't already present.
+
+
+Node related methods
+--------------------
+
+.. method:: Graph.add_node(node[, node_data])
+
+   Adds a new node to the graph if it is not already present. The new
+   node must be a hashable object.
+
+   Arbitrary data can be attached to the node via the optional *node_data*
+   argument.
+
+   .. note:: the node also won't be added to the graph when it is
+      present but currently hidden.
+
+
+.. method:: Graph.hide_node(node)
+
+   Hides a *node* from the graph. The incoming and outgoing edges of
+   the node will also be hidden.
+
+   Raises :class:`altgraph.GraphError` when the node is not (visible)
+   node of the graph.
+
+
+.. method:: Graph.restore_node(node)
+
+   Restores a previously hidden *node*. The incoming and outgoing
+   edges of the node are also restored.
+
+   Raises :class:`altgraph.GraphError` when the node is not a hidden
+   node of the graph.
+
+.. method:: Graph.restore_all_nodes()
+
+   Restores all hidden nodes.
+
+.. method:: Graph.number_of_nodes()
+
+   Return the number of visible nodes in the graph.
+
+.. method:: Graph.number_of_hidden_nodes()
+
+   Return the number of hidden nodes in the graph.
+
+.. method:: Graph.node_list()
+
+   Return a list with all visible nodes in the graph.
+
+.. method:: Graph.hidden_node_list()
+
+   Return a list with all hidden nodes in the graph.
+
+.. method:: node_data(node)
+
+   Return the data associated with the *node* when it was
+   added.
+
+.. method:: Graph.describe_node(node)
+
+   Returns *node*, the node's data and the lists of outgoing
+   and incoming edges for the node.
+
+   .. note::
+
+      the edge lists should not be modified, doing so
+      can result in unpredicatable behavior.
+
+.. method:: Graph.__contains__(node)
+
+   Returns True iff *node* is a node in the graph. This
+   method is accessed through the *in* operator.
+
+.. method:: Graph.__iter__()
+
+   Yield all nodes in the graph.
+
+.. method:: Graph.out_edges(node)
+
+   Return the list of outgoing edges for *node*
+
+.. method:: Graph.inc_edges(node)
+
+   Return the list of incoming edges for *node*
+
+.. method:: Graph.all_edges(node)
+
+   Return the list of incoming and outgoing edges for *node*
+
+.. method:: Graph.out_degree(node)
+
+   Return the number of outgoing edges for *node*.
+
+.. method:: Graph.inc_degree(node)
+
+   Return the number of incoming edges for *node*.
+
+.. method:: Graph.all_degree(node)
+
+   Return the number of edges (incoming or outgoing) for *node*.
+
+Edge related methods
+--------------------
+
+.. method:: Graph.add_edge(head_id, tail_id [, edge data [, create_nodes]])
+
+   Adds a directed edge from *head_id* to *tail_id*. Arbitrary data can
+   be added via *edge_data*.  When *create_nodes* is *True* (the default),
+   *head_id* and *tail_id* will be added to the graph when the aren't
+   already present.
+
+.. method:: Graph.hide_edge(edge)
+
+   Hides an edge from the graph. The edge may be unhidden at some later
+   time.
+
+.. method:: Graph.restore_edge(edge)
+
+   Restores a previously hidden *edge*.
+
+.. method:: Graph.restore_all_edges()
+
+   Restore all edges that were hidden before, except for edges
+   referring to hidden nodes.
+
+.. method:: Graph.edge_by_node(head, tail)
+
+   Return the edge ID for an edge from *head* to *tail*,
+   or :data:`None` when no such edge exists.
+
+.. method:: Graph.edge_by_id(edge)
+
+   Return the head and tail of the *edge*
+
+.. method:: Graph.edge_data(edge)
+
+   Return the data associated with the *edge*.
+
+.. method:: Graph.update_edge_data(edge, data)
+
+   Replace the edge data for *edge* by *data*. Raises
+   :exc:`KeyError` when the edge does not exist.
+
+   .. versionadded:: 0.12
+
+.. method:: Graph.head(edge)
+
+   Return the head of an *edge*
+
+.. method:: Graph.tail(edge)
+
+   Return the tail of an *edge*
+
+.. method:: Graph.describe_edge(edge)
+
+   Return the *edge*, the associated data, its head and tail.
+
+.. method:: Graph.number_of_edges()
+
+   Return the number of visible edges.
+
+.. method:: Graph.number_of_hidden_edges()
+
+   Return the number of hidden edges.
+
+.. method:: Graph.edge_list()
+
+   Returns a list with all visible edges in the graph.
+
+.. method:: Graph.hidden_edge_list()
+
+   Returns a list with all hidden edges in the graph.
+
+Graph traversal
+---------------
+
+.. method:: Graph.out_nbrs(node)
+
+   Return a list of all nodes connected by outgoing edges.
+
+.. method:: Graph.inc_nbrs(node)
+
+   Return a list of all nodes connected by incoming edges.
+
+.. method:: Graph.all_nbrs(node)
+
+   Returns a list of nodes connected by an incoming or outgoing edge.
+
+.. method:: Graph.forw_topo_sort()
+
+   Return a list of nodes where the successors (based on outgoing
+   edges) of any given node apear in the sequence after that node.
+
+.. method:: Graph.back_topo_sort()
+
+   Return a list of nodes where the successors (based on incoming
+   edges) of any given node apear in the sequence after that node.
+
+.. method:: Graph.forw_bfs_subgraph(start_id)
+
+   Return a subgraph consisting of the breadth first
+   reachable nodes from *start_id* based on their outgoing edges.
+
+
+.. method:: Graph.back_bfs_subgraph(start_id)
+
+   Return a subgraph consisting of the breadth first
+   reachable nodes from *start_id* based on their incoming edges.
+
+.. method:: Graph.iterdfs(start[, end[, forward]])
+
+   Yield nodes in a depth first traversal starting at the *start*
+   node.
+
+   If *end* is specified traversal stops when reaching that node.
+
+   If forward is True (the default) edges are traversed in forward
+   direction, otherwise they are traversed in reverse direction.
+
+.. method:: Graph.iterdata(start[, end[, forward[, condition]]])
+
+   Yield the associated data for nodes in a depth first traversal
+   starting at the *start* node. This method will not yield values for nodes
+   without associated data.
+
+   If *end* is specified traversal stops when reaching that node.
+
+   If *condition* is specified and the condition callable returns
+   False for the associated data this method will not yield the
+   associated data and will not follow the edges for the node.
+
+   If forward is True (the default) edges are traversed in forward
+   direction, otherwise they are traversed in reverse direction.
+
+.. method:: Graph.forw_bfs(start[, end])
+
+   Returns a list of nodes starting at *start* in some bread first
+   search order (following outgoing edges).
+
+   When *end* is specified iteration stops at that node.
+
+.. method:: Graph.back_bfs(start[, end])
+
+   Returns a list of nodes starting at *start* in some bread first
+   search order (following incoming edges).
+
+   When *end* is specified iteration stops at that node.
+
+.. method:: Graph.get_hops(start[, end[, forward]])
+
+   Computes the hop distance to all nodes centered around a specified node.
+
+   First order neighbours are at hop 1, their neigbours are at hop 2 etc.
+   Uses :py:meth:`forw_bfs` or :py:meth:`back_bfs` depending on the value of
+   the forward parameter.
+
+   If the distance between all neighbouring nodes is 1 the hop number
+   corresponds to the shortest distance between the nodes.
+
+   Typical usage::
+
+        >>> print graph.get_hops(1, 8)
+        >>> [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5)]
+        # node 1 is at 0 hops
+        # node 2 is at 1 hop
+        # ...
+        # node 8 is at 5 hops
+
+
+Graph statistics
+----------------
+
+.. method:: Graph.connected()
+
+   Returns True iff every node in the graph can be reached from
+   every other node.
+
+.. method:: Graph.clust_coef(node)
+
+   Returns the local clustering coefficient of node.
+
+   The local cluster coefficient is the proportion of the actual number
+   of edges between neighbours of node and the maximum number of
+   edges between those nodes.