The switching method: elaborations
Petr Volf, F.M.J. Willems · TU/e Research Portal · 1998
The switching method [4] is a scheme which combines two universal source coding algorithms. The two universal source coding algorithms both estimate the probability distribution of the source symbols, and the switching method allows an encoder to choose which of the two probability distributions it uses for every source symbol. The switching algorithm is an efficient weighting algorithm that uses this switching method. This paper focuses on the companion algorithm, the algorithm running in parallel to the main CTW-algorithm. 1 The switching method: A short introduction The switching method [4] defines a way in which two modeling algorithms can be combined. Consider a source sequence x1,..., xN. Suppose that two sequential modeling algorithms, A and B, run both along the entire source sequence, and give for every symbol an estimate of its probability distribution. These modeling algorithms could be memoryless estimators, estimators for fixed tree models, or entire universal source coding algorithms on their own. At each moment the encoder in the switching method uses