Statistics Toolbox™

nodesize - Node size

Class

@classregtree

Syntax

sizes = nodesize(t) sizes = nodesize(t,nodes)

Description

sizes = nodesize(t) returns an n-element vector sizes of the sizes of the nodes in the tree t, where n is the number of nodes. The size of a node is defined as the number of observations from the data used to create the tree that satisfy the conditions for the node.

sizes = nodesize(t,nodes) takes a vector nodes of node numbers and returns the sizes for the specified nodes.

Example

Create a classification tree for Fisher's iris data:

load fisheriris;

t = classregtree(meas,species,...
                 'names',{'SL' 'SW' 'PL' 'PW'})
t = 
Decision tree for classification
1  if PL<2.45 then node 2 else node 3
2  class = setosa
3  if PW<1.75 then node 4 else node 5
4  if PL<4.95 then node 6 else node 7
5  class = virginica
6  if PW<1.65 then node 8 else node 9
7  class = virginica
8  class = versicolor
9  class = virginica

view(t)

sizes = nodesize(t)
sizes =
   150
    50
   100
    54
    46
    48
     6
    47
     1

Reference