logb

Version 1.2.0.1 (1.56 KB) by Brett Shoelson
Calculate the log of a number/matrix using a user-specified base.
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Updated 1 Sep 2016

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FUNCTION Y = LOGB(X,B)
logb: Calculates the logarithm of x to user-specified base b.

USAGE: y = logb(x,b)

(A trivial but useful function for arbitrary-base log calculations.)

Arguments:
Y: the base 'b' logarithm of input x
B: The base of the logarithmic calculation (default, e). Note that if B is non-scalar, it must be the same size as X. In that case, the log transformation will be element-by-element.

Examples:
1) To calculate the base 5 logarithm of 3:
y = logb(3,5)

2) To calculate element-wise the log of a non-scalar input using different bases:
y = logb(magic(3),[1 2 3; 4 5 6; 7 8 9]);

See also: log, log10, log2

Cite As

Brett Shoelson (2025). logb (https://www.mathworks.com/matlabcentral/fileexchange/14866-logb), MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2007a
Compatible with any release
Platform Compatibility
Windows macOS Linux
Categories
Find more on Log Plots in Help Center and MATLAB Answers
Acknowledgements

Inspired: Order of magnitude of number

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Version Published Release Notes
1.2.0.1

Updated license
1.2.0.0

Updated M file and license text file copyright to The MathWorks, Inc.

1.1.0.0

added copyright
1.0.0.0

Addresses some good-programming-practices suggestions made by John D'Errico. Better description, help, error checking.