Unary coding: Difference between revisions

Revision as of 14:08, 28 November 2009

Revision as of 11:38, 23 December 2009

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:<math>\operatorname{P}(n) \ge \operatorname{P}(n+1) + \operatorname{P}(n+2)\, </math>

for <math>n=1,2,3,...</math>. Although it is the optimal symbol-by-symbol coding for such probability distributions, its optimality can, like that of [[HuffmanGolomb coding]], be over-stated. [[Arithmetic coding]] hasachieves better compression capability for the lastgeometric two distributions mentioned abovedistribution because it does not consider input symbols independently, but rather implicitly groups the inputs. For the same reason, [[arithmetic encoding]] performs better for general probability distributions, as in the last case above.

A modified unary encoding is used in [[UTF-8]]. Unary codes are also used in split-index schemes like the [[Golomb Rice code]]. Unary coding is [[Prefix-free code|prefix-free]], and can be uniquely decoded.

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==See also==

*[[Thermometer code]]

*[[Unary numeral system]]

==References==