Results in the natural logarithm (ln) of the input signal

Ln(S)

Polybench reference manual · Last updated 2026-06-18

This operator calculates the natural Logarithm (ln).
The ln is applied to every input value on every channel. The result is written to the same channel at the output.

Symbol in the Object Toolbox

Operator ports

Input S: Floating point values
Output ln(S): Floating point values

A calculation of ln of the value 0 or negative values is not allowed. If the ln calculation cannot be performed, the operator outputs the last valid sample once more. The symbol of the ln will then display a warning.

Properties

Find more information about changing properties here: "Properties Viewer"

Caption

type: Word or phrase
The name of the object in the project. This name must not contain '.', '$' nor '@' characters.

For more information about the rules and usage of the Caption property, please refer to "Caption property - background and usage".

Documentation

type: See description
Optional documentation of this object. If this object is an operator, the Documentation text is displayed below the operator symbol.

Examples

Example: Log - Ln - Exp Demo

This demo shows the behavior of the 10Log, Ln and e^y operators. Press 'Start displays' first so that the numerical displays display values. Then type values in the Input Field.
Note the behavior of the operators when they are forced to do illegal calculations. They will show a warning about any problems, but keep their output unchanged.
Examples\DF0411129_001_ln_Demo.xmc