Machine Learning with R Cookbook - Second Edition

How to do it...

Perform the following steps to measure the prediction performance of the trained neural network:

1. First, generate a prediction probability matrix based on a trained neural network and the testing dataset, testset:

        > net.predict = compute(network, testset[-5])$net.result

2. Then, obtain other possible labels by finding the column with the greatest probability:

        > net.prediction = c("versicolor", "virginica",        "setosa")[apply(net.predict, 1, which.max)]

3. Generate a classification table based on the predicted labels and the labels of the testing dataset:

> predict.table = table(testset$Species, net.prediction)> predict.tableOutput            predictionsetosa versicolor virginicasetosa        20  0  0  versicolor   0 19  1  virginica    0  2  16

4. Next, generate ...