Definition: (1) Any function that is a constant times the logarithm of the argument: f(x)=c log x. (2) In complexity theory, when the measure of computation, m(n) (usually execution time or memory space), is bounded by a logarithmic function of the problem size, n. More formally m(n) = O(log n). (3) Sometimes imprecisely used to mean polylogarithmic.

Generalization (I am a kind of ...)
sublinear time algorithm.

See also linear, polynomial, exponential.

Author: PEB

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Entry modified 17 December 2004.
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Cite this as:
Paul E. Black, "logarithmic", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 17 December 2004. (accessed TODAY) Available from: