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Comment by p1esk

14 hours ago

And yet the best learning algorithm we have is derivative-free!

Yes, SVMs and Random Forests still rule the many worlds of classification problems often not in the spotlight.

  • Support Vector Machines involve solving a large QP optimization problem... which is often done by running a variant of gradient descent (or one of the second- or quasi-second-order optimization algorithms, which involves finding the Hessian as well as the gradient)

    • I was under the impression that solving QP optimization problems (subject to constraints) was largely performed by SMO.

  • Back when I was a researcher, I had a classification problem where the default random forest classifier built into scikitlearn completely dominated the neural method. The best numbers we got were something like a ~30% improvement from baseline for the neural network to ~95% for the random forest.

    The disparity was so large that I was certain I must have made a mistake and I spent a few hours debugging, and then a few hours more trying different neural architectures.

    Turns out this is just a super common experience for anyone in NNs who would also try the more established learning algorithms.