Classification edge by resubstitution
edge = resubEdge(obj)
Discriminant analysis classifier, produced using
Classification edge obtained by resubstituting the training data into the calculation of edge.
Estimate 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.
Train a discriminant analysis classifier.
Mdl = fitcdiscr(meas,species);
Compute the resubstitution edge.
redge = resubEdge(Mdl)
redge = 0.9454
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.
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.
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.