Digraph object (Multivariate Analysis Toolbox for Matlab®)

This object describes a mathematical entity known as a directed graph (digraph). This is a graph, whose branches are directed. I chose to represent the directionality by an antisymmetric matrix D, which is the matrix of target height differences. A value D(i,j) means that node i is a distance D(i,j) "above" node j. This objects inherits from the parent object graph.

Navigate to:     General Description     Class Structure     Class Construction     Class Functions

Each field can be accessed by the dot (.) operation, or by the GET function. The GET function can work on multiple instances simultaneously. Most fields, except for those that are Dependent, can be modified using the dot (.) operation, or by the SET function.

		Field	Description	Type	Default	Dedicated Get/Set Function
		thd	target-height-differences matrix	double matrix	[]
		name	Inherited from graph. name of object, should be short and used as identifier. This field will never be empty.	string	'unnamed'
		description	Inherited from graph. verbal description of the class content.	string	''
		source	Inherited from graph. verbal description of the source of information.	string	''
		type	Inherited from graph. type of graph.	string	'general graph'
		node_name	Inherited from graph. names of all nodes.	cell array of strings	{}	nodenames
		node_mass	Inherited from graph. mass of each node.	double vector	[]
		node_cfield	Inherited from graph. user-specific node customized fields.	cell array of values	{}
		node_cfield_name	Inherited from graph. names of node customized fields.	cell array of strings	{}
		weights	Inherited from graph. symmetric sparse weight matrix.	double matrix	[]
	Dependent	no_nodes	Inherited from graph. number of nodes in the graph.	integer scalar	0	nonodes
	Dependent	no_node_cfields	Inherited from graph. number of customized fields.	integer scalar	0
	Dependent	no_edges	Inherited from graph. number of edges in the graph.	integer vector	0	noedges

Empty instance (scalar)

an empty digraph instance, with all fields initialized to their default values.

syntax: dg = digraph;

Empty instance (matrix)

an array of empty digraph instances.

syntax: dg = digraph(size,'size');

Copy constructor

one digraph instance is copied into another.

syntax: dg_destination = digraph(dg_origin);

Construction by field names

an instance is formed by directly providing field values. Any field which is not dependent is permitted.

syntax: dg = digraph(field_name, field_value, ...);

Enumerating all possible DAGs

Enumerates all DAGs with a certain number of nodes, including non-connected ones.

syntax: dg = digraph('enum',no_nodes,node_names);

Computations:

balance

computes the balance vector.

dag2code

finds the DAG-code of a DAG.

laplacian

computes the Laplacian of a graph. Source: graph.

vstruct

finds nodes that are center of a V-structure.

Customized fields manipulations:

alloccfield

allocates a new customized field to a graph. Source: graph.

cfieldexist

finds whether a customized field exists in a graph. Source: graph.

cfieldnames

lists the customized fields in a GRAPH object. Source: graph.

getcfield

retrieves a customized field from a graph. Source: graph.

setcfield

sets values for a customized field of GRAPHs. Source: graph.

Display:

show

displays class content. Source: graph.

I/O functions:

dump

writes a DIGRAPH to disk.

Information extraction:

iodegree

computes the in and out degrees of a digraph.

iscyclic

finds whether a DIGRAPH is cyclic or not.

leaves

finds these nodes that are leaves.

nodeid

finds the IDs of a list of nodes. Source: graph.

parents

finds the parents of specific nodes.

Maintenance:

verify

computes missing fields.

SET/GET functions:

get

get method

nodenames

retrieves the name of the nodes in the graph. Source: graph.

noedges

retrieves the number of edges in GRAPH objects. Source: graph.

nonodes

retrieves the number of nodes in GRAPH objects. Source: graph.

set

set method

Transformations:

swap

replaces the indices of two nodes.

Visualization:

eigenproj

computes the eigenprojection of a graph. Source: graph.

view

plots a DIGRAPH