The brain data contains two objects: brain.x, microarray
expression data for 42 brain cancer samples and brain.y, the class
labels for these samples.
data(brain)An expression data matrix (42x5597) brain.x and a class label
vector (42) brain.y for 42 samples.
brain.y is the class labels of the 42 samples. brain.x is
the microarray expression data matrix with each row representing a sample.
Guo, Y. et al. (2004) Regularized Discriminant Analysis and Its Application in Microarrays, Technical Report, Department of Statistics, Stanford University.