LogRegB (PQL)
Calculates the logorithmic regression of a set and returns the value of 'b' in the regression line, y = a + b*ln(x)
- Returned Output: Numeric
- Library: PQL \ Semantic \ Statistical
- Version: 2023.00.000
- Compatibility: Pyramid Query Language (PQL) data sources
Syntax
* Click on the function's arguments above for more details on the input values.
Comments
The LogRegX functions calculate the logarithmic regression for the supplied values / measures, and then return one of the values associated with that regression. The logarithmic regression functions are:
- LogRegA (PQL) - Returns the value of a, the constant or vertical shift.
- LogRegB (PQL) - Returns the value of b, the rate of change in y.
- LogRegPoint (PQL) - Returns the y-value for the regression line at a particular value of x.
- LogRegR2 (PQL) - Returns the coefficient of determination, R2.
Arguments
LogRegB returns the value of b (the rate of change in y) for the logarithmic regression, and requires the following arguments:
- The List parameter is a list or set of elements from an existing hierarchy in the model.
- The hierarchy name needs to be a Unique Name with the format
[dimension].^[hierarchy]or[table].[column]. - The Numeric parameters following the set are each evaluated against the specified set to obtain the values for the y- and x-axes, respectively.
- The values can be returned from a hierarchy as a numeric expression.
- If the optional numeric value is not supplied, the current context of the cells is used for the x-axis.
Remarks
- For details on how to employ and use this function see the semantic calculation overview.
Examples
When drawing a logarithmic regression across the last 10 date-key members, where Sales is regressed against Profit, the value of b (the rate of change in y) is returned using the following function:
LogRegB( Tail([Date].[dateKey].allmembers, 10), [Measures].[Fact Sales], [Measures].[Profit] )
Tip: Alternatively, use Last in place of Tail. Last and Tail are aliases for the function that retrieves the last X elements in a given hierarchy. For more information, see Tail (PQL).