Polybench® for biosignals / reference 1.34.1
Results in the natural logarithm of the input value



Calculates the natural logarithm of the input vector, field by field.

By default, this operator will not use complex calculation to determine the output, and will give an operation error when a wrong input (like the natural logarithm of a negative number) is detected. If this happens, the last valid output vector will be put at the output again.

If required, the user can set the ComplexOutput property to true. This will allow the analysis of natural logarithms of negative numbers or of complex numbers.

Operator ports

Input V1: Specific sample type, see below.

Output ln(V1): Floating point value buffers


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

type: True or False
Whether the output can contain complex numbers
Select one of those presets:
True or False
True may also be read like 'yes' and false like 'no'

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".

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


If the ComplexOutput property is set to false (default), the operator will only use the real part of the incoming vector and will calculate, field by field, its natural logarithm.

The operator detects invalid values, and will state an error message when such values are detected. If the ln function results in an invalid value in any field of the vector, then the last valid vector will remain unchanged at the output.

The ln function in the default setup results in invalid values, when the input value is negative.

If the ComplexOutput property is set to true, negative input values will result in a complex output. The output is evaluated in the following manner:

If a specific field in the input vector is indicated by r * e ^ iA (complex number in polar form), the output will be:

ln(Vin) = ln(r) + iA