resubEdge

Class: ClassificationDiscriminant

Classification edge by resubstitution

Syntax

edge = resubEdge(obj)

Description

edge = resubEdge(obj) returns the classification edge obtained by obj on its training data.

Input Arguments

obj

Discriminant analysis classifier, produced using fitcdiscr.

Output Arguments

edge

Classification edge obtained by resubstituting the training data into the calculation of edge.

Definitions

Edge

The edge is the weighted mean value of the classification margin. The weights are class prior probabilities. If you supply additional weights, those weights are normalized to sum to the prior probabilities in the respective classes, and are then used to compute the weighted average.

Margin

The classification margin is the difference between the classification score for the true class and maximal classification score for the false classes.

The classification margin is a column vector with the same number of rows as in the matrix X. A high value of margin indicates a more reliable prediction than a low value.

Score

For discriminant analysis, the score of a classification is the posterior probability of the classification. For the definition of posterior probability in discriminant analysis, see Posterior Probability.

Examples

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Esimtate the Resubstitution Edge of Discriminant Analysis Classifiers

Estimate the quality of a discriminant analysis classifier for Fisher's iris data by resubstitution.

Load Fisher's iris data set.

load fisheriris

Train a discriminant analysis classifier.

Mdl = fitcdiscr(meas,species);

Compute the resubstitution edge.

redge = resubEdge(Mdl)
redge =

    0.9454

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