NAME¶
struct::graph_v1 - Create and manipulate directed graph objects
SYNOPSIS¶
package require
Tcl 8.2
package require
struct::graph ?1.2.1?
graphName option ?
arg arg ...?
graphName destroy
graphName arc append arc ?-key
key?
value
graphName arc delete arc ?
arc ...?
graphName arc exists arc
graphName arc get arc ?-key
key?
graphName arc getall arc
graphName arc keys arc
graphName arc keyexists arc ?-key
key?
graphName arc insert start end ?
child?
graphName arc lappend arc ?-key
key?
value
graphName arc set arc ?-key
key? ?
value?
graphName arc source arc
graphName arc target arc
graphName arc unset arc ?-key
key?
graphName arcs ?-key
key? ?-value
value?
?-in|-out|-adj|-inner|-embedding
nodelist?
graphName node append node ?-key
key?
value
graphName node degree ?-in|-out?
node
graphName node delete node ?
node ...?
graphName node exists node
graphName node get node ?-key
key?
graphName node getall node
graphName node keys node
graphName node keyexists node ?-key
key?
graphName node insert ?
child?
graphName node lappend node ?-key
key?
value
graphName node opposite node arc
graphName node set node ?-key
key? ?
value?
graphName node unset node ?-key
key?
graphName nodes ?-key
key? ?-value
value?
?-in|-out|-adj|-inner|-embedding
nodelist?
graphName get ?-key
key?
graphName getall
graphName keys
graphName keyexists ?-key
key?
graphName set ?-key
key? ?
value?
graphName swap node1 node2
graphName unset ?-key
key?
graphName walk node ?-order
order? ?-type
type? ?-dir
direction? -command
cmd
DESCRIPTION¶
The
::struct::graph command creates a new graph object with an associated
global Tcl command whose name is
graphName. This command may be used to
invoke various operations on the graph. It has the following general form:
- graphName option ?arg arg ...?
- Option and the args determine the exact behavior of the
command.
A directed graph is a structure containing two collections of elements, called
nodes and
arcs respectively, together with a relation
("connectivity") that places a general structure upon the nodes and
arcs.
Each arc is connected to two nodes, one of which is called the
source and
the other the
target. This imposes a direction upon the arc, which is
said to go from the source to the target. It is allowed that source and target
of an arc are the same node. Such an arc is called a
loop. Whenever a
node is source or target of an arc both are said to be
adjacent. This
extends into a relation between nodes, i.e. if two nodes are connected through
at least one arc they are said to be
adjacent too.
Each node can be the source and target for any number of arcs. The former are
called the
outgoing arcs of the node, the latter the
incoming
arcs of the node. The number of edges in either set is called the
in- resp. the
out-degree of the node.
In addition to maintaining the node and arc relationships, this graph
implementation allows any number of keyed values to be associated with each
node and arc.
The following commands are possible for graph objects:
- graphName destroy
- Destroy the graph, including its storage space and associated
command.
- graphName arc append arc ?-key key?
value
- Appends a value to one of the keyed values associated with an
arc. If no key is specified, the key data is
assumed.
- graphName arc delete arc ?arc ...?
- Remove the specified arcs from the graph.
- graphName arc exists arc
- Return true if the specified arc exists in the graph.
- graphName arc get arc ?-key key?
- Return the value associated with the key key for the arc. If
no key is specified, the key data is assumed.
- graphName arc getall arc
- Returns a serialized list of key/value pairs (suitable for use with [
array set]) for the arc.
- graphName arc keys arc
- Returns a list of keys for the arc.
- graphName arc keyexists arc ?-key key?
- Return true if the specified key exists for the arc. If no
key is specified, the key data is assumed.
- graphName arc insert start end
?child?
- Insert an arc named child into the graph beginning at the node
start and ending at the node end. If the name of the new arc
is not specified the system will generate a unique name of the form
arc x.
- graphName arc lappend arc ?-key key?
value
- Appends a value (as a list) to one of the keyed values associated
with an arc. If no key is specified, the key data is
assumed.
- graphName arc set arc ?-key key?
?value?
- Set or get one of the keyed values associated with an arc. If no key is
specified, the key data is assumed. Each arc that is added to a
graph has the empty string assigned to the key data automatically.
An arc may have any number of keyed values associated with it. If
value is not specified, this command returns the current value
assigned to the key; if value is specified, this command assigns
that value to the key.
- graphName arc source arc
- Return the node the given arc begins at.
- graphName arc target arc
- Return the node the given arc ends at.
- graphName arc unset arc ?-key key?
- Remove a keyed value from the arc arc. If no key is specified, the
key data is assumed.
- graphName arcs ?-key key? ?-value value?
?-in|-out|-adj|-inner|-embedding nodelist?
- Return a list of arcs in the graph. If no restriction is specified a list
containing all arcs is returned. Restrictions can limit the list of
returned arcs based on the nodes that are connected by the arc, on the
keyed values associated with the arc, or both. The restrictions that
involve connected nodes have a list of nodes as argument, specified after
the name of the restriction itself.
- -in
- Return a list of all arcs whose target is one of the nodes in the
nodelist.
- -out
- Return a list of all arcs whose source is one of the nodes in the
nodelist.
- -adj
- Return a list of all arcs adjacent to at least one of the nodes in the
nodelist. This is the union of the nodes returned by -in and
-out.
- -inner
- Return a list of all arcs adjacent to two of the nodes in the
nodelist. This is the set of arcs in the subgraph spawned by the
specified nodes.
- -embedding
- Return a list of all arcs adjacent to exactly one of the nodes in the
nodelist. This is the set of arcs connecting the subgraph spawned
by the specified nodes to the rest of the graph.
- -key key
- Limit the list of arcs that are returned to those arcs that have an
associated key key.
- -value value
- This restriction can only be used in combination with -key. It
limits the list of arcs that are returned to those arcs whose associated
key key has the value value.
The restrictions imposed by either
-in,
-out,
-adj,
-inner, or
-embedded are applied first. Specifying more than one
of them is illegal. At last the restrictions set via
-key (and
-value) are applied. Specifying more than one
-key (and
-value) is illegal.
- graphName node append node ?-key key?
value
- Appends a value to one of the keyed values associated with an
node. If no key is specified, the key data is
assumed.
- graphName node degree ?-in|-out? node
- Return the number of arcs adjacent to the specified node. If one of
the restrictions -in or -out is given only the incoming
resp. outgoing arcs are counted.
- graphName node delete node ?node ...?
- Remove the specified nodes from the graph. All of the nodes' arcs will be
removed as well to prevent unconnected arcs.
- graphName node exists node
- Return true if the specified node exists in the graph.
- graphName node get node ?-key key?
- Return the value associated with the key key for the node.
If no key is specified, the key data is assumed.
- graphName node getall node
- Returns a serialized list of key/value pairs (suitable for use with [
array set]) for the node.
- graphName node keys node
- Returns a list of keys for the node.
- graphName node keyexists node ?-key key?
- Return true if the specified key exists for the node. If no
key is specified, the key data is assumed.
- graphName node insert ?child?
- Insert a node named child into the graph. The nodes has no arcs
connected to it. If the name of the new child is not specified the system
will generate a unique name of the form nodex.
- graphName node lappend node ?-key key?
value
- Appends a value (as a list) to one of the keyed values associated
with an node. If no key is specified, the key data is
assumed.
- graphName node opposite node arc
- Return the node at the other end of the specified arc, which has to
be adjacent to the given node.
- graphName node set node ?-key key?
?value?
- Set or get one of the keyed values associated with a node. If no key is
specified, the key data is assumed. Each node that is added to a
graph has the empty string assigned to the key data automatically.
A node may have any number of keyed values associated with it. If
value is not specified, this command returns the current value
assigned to the key; if value is specified, this command assigns
that value to the key.
- graphName node unset node ?-key key?
- Remove a keyed value from the node node. If no key is specified,
the key data is assumed.
- graphName nodes ?-key key? ?-value value?
?-in|-out|-adj|-inner|-embedding nodelist?
- Return a list of nodes in the graph. Restrictions can limit the list of
returned nodes based on neighboring nodes, or based on the keyed values
associated with the node. The restrictions that involve neighboring nodes
have a list of nodes as argument, specified after the name of the
restriction itself.
The possible restrictions are the same as for method arcs. The set of
nodes to return is computed as the union of all source and target nodes
for all the arcs satisfying the restriction as defined for
arcs.
- graphName get ?-key key?
- Return the value associated with the key key for the graph. If no
key is specified, the key data is assumed.
- graphName getall
- Returns a serialized list of key/value pairs (suitable for use with [
array set]) for the whole graph.
- graphName keys
- Returns a list of keys for the whole graph.
- graphName keyexists ?-key key?
- Return true if the specified key exists for the whole graph. If no
key is specified, the key data is assumed.
- graphName set ?-key key? ?value?
- Set or get one of the keyed values associated with a graph. If no key is
specified, the key data is assumed. Each graph has the empty string
assigned to the key data automatically. A graph may have any number
of keyed values associated with it. If value is not specified, this
command returns the current value assigned to the key; if value is
specified, this command assigns that value to the key.
- graphName swap node1 node2
- Swap the position of node1 and node2 in the graph.
- graphName unset ?-key key?
- Remove a keyed value from the graph. If no key is specified, the key
data is assumed.
- graphName walk node ?-order order? ?-type
type? ?-dir direction? -command cmd
- Perform a breadth-first or depth-first walk of the graph starting at the
node node going in either the direction of outgoing or opposite to
the incoming arcs.
The type of walk, breadth-first or depth-first, is determined by the value
of type; bfs indicates breadth-first, dfs indicates
depth-first. Depth-first is the default.
The order of the walk, pre-order, post-order or both-order is determined by
the value of order; pre indicates pre-order, post
indicates post-order, both indicates both-order. Pre-order is the
default. Pre-order walking means that a node is visited before any of its
neighbors (as defined by the direction, see below). Post-order
walking means that a parent is visited after any of its neighbors.
Both-order walking means that a node is visited before and after
any of its neighbors. The combination of a bread-first walk with post- or
both-order is illegal.
The direction of the walk is determined by the value of dir;
backward indicates the direction opposite to the incoming arcs,
forward indicates the direction of the outgoing arcs.
As the walk progresses, the command cmd will be evaluated at each
node, with the mode of the call ( enter or leave) and values
graphName and the name of the current node appended. For a
pre-order walk, all nodes are entered, for a post-order all nodes
are left. In a both-order walk the first visit of a node enters it,
the second visit leaves it.
BUGS, IDEAS, FEEDBACK¶
This document, and the package it describes, will undoubtedly contain bugs and
other problems. Please report such in the category
struct :: graph of
the
Tcllib Trackers [
http://core.tcl.tk/tcllib/reportlist]. Please also
report any ideas for enhancements you may have for either package and/or
documentation.
KEYWORDS¶
cgraph, graph
CATEGORY¶
Data structures
COPYRIGHT¶
Copyright (c) 2002 Andreas Kupries <andreas_kupries@users.sourceforge.net>