2020

The role of regularization in classification of high-dimensional noisy Gaussian mixture

Mignacco, Francesca, Krzakala, Florent, Lu, Yue M. et al.

Understand

We consider a high-dimensional mixture of two Gaussians in the noisy regime where even an oracle knowing the centers of the clusters misclassifies a small but finite fraction of the points.

  • We provide a rigorous analysis of the generalization error of regularized convex classifiers, including ridge, hinge and logistic regression, in the high-dimensional limit where the number $n$ of samples and their dimension $d$ go to infinity while their ratio is fixed to $\alpha= n/d$.
  • We discuss surprising effects of the regularization that in some cases allows to reach the Bayes-optimal performances.
  • We also illustrate the interpolation peak at low regularization, and analyze the role of the respective sizes of the two clusters.

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