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Structured nonlinear variable selection
Proceedings of the 34th Conference on Uncertainty in Artificial Intelligence, PMLR R16:22-31, 2018.
Abstract
We investigate structured sparsity methods for variable selection in regression problems where the target depends nonlinearly on the inputs. We focus on general nonlinear func- tions not limiting a priori the function space to additive models. We propose two new regu- larizers based on partial derivatives as nonlin- ear equivalents of group lasso and elastic net. We formulate the problem within the frame- work of learning in reproducing kernel Hilbert spaces and show how the variational problem can be reformulated into a more practical fi- nite dimensional equivalent. We develop a new algorithm derived from the ADMM principles that relies solely on closed forms of the proxi- mal operators. We explore the empirical prop- erties of our new algorithm for Nonlinear Vari- able Selection based on Derivatives (NVSD) on a set of experiments and confirm favourable properties of our structured-sparsity models and the algorithm in terms of both prediction and variable selection accuracy.