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  1. Preface
  2. The Transformation Language
  3. Constants
  4. Operators
  5. Variables
  6. Dates
  7. Functions

Transformation Language Reference

Transformation Language Reference

LOG

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. (
Data Integration Service
does not write the row.
)
0
5
Error. (
Data Integration Service
does not write the row.
)
10
-2
Error. (
Data Integration Service
does not write the row.
)
The
Data 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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