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Creating Custom Functions
Custom Function API Reference

Transformation Language Reference

10.4.0
- 10.5.6
- 10.5.1
- 10.5

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LOG

Returns the logarithm of a numeric value. Most often, you use this function to analyze scientific data rather than business data.

Syntax

LOG( base, exponent )

The following table describes the arguments for this command:

Argument	Required/ Optional	Description
base	Required	The base of the logarithm. Must be a positive numeric value other than 0 or 1. Any valid transformation expression that evaluates to a positive number other than 0 or 1.
exponent	Required	The exponent of the logarithm. Must be a positive numeric value greater than 0. Any valid transformation expression that evaluates to a positive number greater than 0.

Return Value

Double value.

NULL if a value passed to the function is NULL.

Example

The following expression returns the logarithm for all values in the NUMBERS port:

LOG( BASE, EXPONENT )

BASE	EXPONENT	RETURN VALUE
15	1	0
.09	10	-0.956244644696599
NULL	18	NULL
35.78	NULL	NULL
-9	18	Error. ( PowerCenter Integration Service does not write the row. )
0	5	Error. ( PowerCenter Integration Service does not write the row. )
10	-2	Error. ( PowerCenter Integration Service does not write the row. )

The

PowerCenter Integration Service

displays an error and does not write the row if you pass a negative number, 0, or 1 as a base value, or if you pass a negative value for the exponent.

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Table of Contents

Transformation Language Reference

Transformation Language Reference

LOG

LOG

Syntax

Return Value

Example