(redirected from Logarithm function)
Also found in: Dictionary, Thesaurus, Encyclopedia.


If a number, x, is expressed as a power of another number, y, that is, if x = yn, then n is said to be the logarithm of x to base y. Common logarithms are to the base 10; natural or Napierian logarithms are to the base e, a mathematical constant.
[G. logos, word, ratio, + arithmos, number]


a mathematical device.

common logarithm
the value of the power when a number is expressed as to the power of 10 (has the base 10). Thus 100 expressed as to the power of 10 is 102 and the log of 100 is 2.
Napierian logarithm
see natural logarithm (below).
natural logarithm
as for common logarithm, except that the base is e or 2.178. Called also Napierian logarithm.
References in periodicals archive ?
Here and throughout the paper, unless stated otherwise, our logarithmic function logx is a natural logarithm function (following the notation of [7]).
The relation (1) becomes linear if we apply the logarithm function, as follows:
As you can observe in the map of the Figure 5(a), the distortion of the anomalies in a form of broken lines that were identified in the rectangles of the Figure 3(b) have been attenuated (zigzag effect), while in a process of compression through a logarithm function was applied to the Map 5(a) getting the result of the Figure 5(b).
Buzaglo's introduction presents the notion of nonarbitrary concept expansion via examples: "The concept of square root was expanded to include the negative numbers; the concept of power, originally defined only for the natural numbers, was expanded to include zero, fractions, and real and complex numbers; the logarithm function, which was originally defined only for positive numbers, was expanded to the negative numbers" (p.