knnfwd

Purpose

Forward propagation through a K-nearest-neighbour classifier.

Synopsis


[y, l] = knnfwd(net, x)

Description

[y, l] = knnfwd(net, x) takes a matrix x of input vectors (one vector per row) and uses the k-nearest-neighbour rule on the training data contained in net to produce a matrix y of outputs and a matrix l of classification labels. The nearest neighbours are determined using Euclidean distance. The ijth entry of y counts the number of occurrences that an example from class j is among the k closest training examples to example i from x. The matrix l contains the predicted class labels as an index 1..N, not as 1-of-N coding.

Example


net = knn(size(xtrain, 2), size(t_train, 2), 3, xtrain, t_train);
y = knnfwd(net, xtest);
conffig(y, t_test);
Creates a 3 nearest neighbour model net and then applies it to the data xtest. The results are plotted as a confusion matrix with conffig.

See Also

kmeans, knn
Pages: Index

Copyright (c) Ian T Nabney (1996-9)