Search results
Results from the WOW.Com Content Network
A colourful way of describing such a circumstance, introduced by David Wolpert and William G. Macready in connection with the problems of search [1] and optimization, [2] is to say that there is no free lunch. Wolpert had previously derived no free lunch theorems for machine learning (statistical inference). [3]
In machine learning, hyperparameter optimization [1] or tuning is the problem of choosing a set of optimal hyperparameters for a learning algorithm. A hyperparameter is a parameter whose value is used to control the learning process, which must be configured before the process starts. [2] [3]
Proximal gradient methods are applicable in a wide variety of scenarios for solving convex optimization problems of the form + (),where is convex and differentiable with Lipschitz continuous gradient, is a convex, lower semicontinuous function which is possibly nondifferentiable, and is some set, typically a Hilbert space.
An autoencoder is a type of artificial neural network used to learn efficient codings of unlabeled data (unsupervised learning).An autoencoder learns two functions: an encoding function that transforms the input data, and a decoding function that recreates the input data from the encoded representation.
From a Bayesian point of view, many regularization techniques correspond to imposing certain prior distributions on model parameters. [6] Regularization can serve multiple purposes, including learning simpler models, inducing models to be sparse and introducing group structure [clarification needed] into the learning problem.
Random optimization (RO) is a family of numerical optimization methods that do not require the gradient of the optimization problem and RO can hence be used on functions that are not continuous or differentiable. Such optimization methods are also known as direct-search, derivative-free, or black-box methods.
Empirically, for machine learning heuristics, choices of a function that do not satisfy Mercer's condition may still perform reasonably if at least approximates the intuitive idea of similarity. [6] Regardless of whether k {\displaystyle k} is a Mercer kernel, k {\displaystyle k} may still be referred to as a "kernel".
A finite-state machine just looks at the input signal and the current state: it has no stack to work with, and therefore is unable to access previous values of the input. It can only choose a new state, the result of following the transition. A pushdown automaton (PDA) differs from a finite state machine in two ways: