Control of sparseness for feature selection

Abstract

In linear discriminant (LD) analysis high sample size/feature ratio is desirable. The linear programming procedure (LP) for LD identification handles the curse of dimensionality through simultaneous minimization of the L1 norm of the classification errors and the LD weights. The sparseness of the solution - the fraction of features retained - can be controlled by a parameter in the objective function. By qualitatively analyzing the objective function and the constraints of the problem, we show why sparseness arises. In a sparse solution, large values of the LD weight vector reveal those individual features most important for the decision boundary. © Springer-Verlag 2004.