ntree

NTREE constructor

Syntax

T = ntree(ord,d)

T = ntree(ord,d,s)

T = ntree(ord,d,s,u)

[T,nb] = ntree(___)

Description

T = ntree(ord,d) returns an NTREE object, which is a complete tree of order ord and depth d.

• T = ntree is equivalent to T = ntree(2,0).

• T = ntree(ord) is equivalent to T = ntree(ord,0).

T = ntree(ord,d,s) sets a "split scheme" for nodes.

T = ntree(ord,d,s,u) sets the user data field of T.

You can also specify function inputs this way: T = ntree('order',ord,'depth',d,'spsch',s,'ud',u). For unspecified inputs, the defaults are ord = 2 and d = 0 , s = ones(ord,1]) , u = {}.

[T,nb] = ntree(___) also returns the number of terminal nodes (leaves) of T.

Examples

Create NTREE Object

Create a binary tree (a tree of order 2) of depth 3.

t2 = ntree(2,3);

Use the plot tree GUI plot to plot the tree.

plot(t2)

Create a quadtree (a tree of order 4) of depth 2. Split all except the third node.

t4 = ntree(4,2,[1 1 0 1]);
plot(t4)

Input Arguments

ord — Tree order

2 (default) | positive integer

Tree order, specified as a positive integer.

Data Types: double

d — Tree depth

0 (default) | nonnegative integer

Tree depth, specified as a nonnegative integer.

Data Types: double

s — Split scheme

ones(ord,1) (default) | logical array

Split scheme, specified as an ord-by-1 logical array. The root of the tree can be split and it has ord children. You can split the jth child if s(j) = 1. Each node that you can split has the same property as the root node.

Example: T = ntree(2,3,[1 0]) splits the first node at every level.

u — User data

{} (default) | array | cell array | structure array

User data to set in the ud field of T, specified as an array, cell array, or structure array.

Example: t = ntree(2,3,[0 1],{1,"aa",rand(3,3)})

Output Arguments

T — Tree

NTREE object

Tree, returned as a NTREE object.

The NTREE object has these fields:

wtbo	Parent object
order	Tree order
depth	Tree depth
spsch	Split scheme for nodes
tn	Column vector with terminal node indices

The wtbo parent object has these fields:

wtboInfo	Object information
ud	User data field

For more information on object fields, type:

help ntree/get

nb — Number of terminal nodes

integer

Number of terminal nodes (leaves) of T.

Data Types: double

Version History

Introduced before R2006a