pow
This page explains how to use the pow function in APL.
Use the pow function in APL to raise a base value to a given exponent: base^exponent. The function accepts any real base and exponent.
pow is useful whenever you need to apply a power function to a metric, such as squaring deviations for variance calculations, computing exponential growth factors, scaling values by a fractional power, or inverting a power transformation. It's more flexible than exp, exp2, or exp10 because you can specify any base.
Usage
Syntax
pow(base, exponent)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
base | real | Yes | The base value. |
exponent | real | Yes | The exponent to raise the base to. |
Returns
base raised to the power exponent: base^exponent.
Example
Use pow to square the deviation of each request's duration from a 200 ms baseline.
Query
['sample-http-logs']
| extend deviation = req_duration_ms - 200.0
| extend squared_deviation = pow(deviation, 2)
| project _time, id, req_duration_ms, squared_deviation
| order by squared_deviation descOutput
| _time | id | req_duration_ms | squared_deviation |
|---|---|---|---|
| 2024-11-14 10:00:00 | user-1 | 1200.0 | 1000000.0 |
| 2024-11-14 10:01:00 | user-2 | 80.0 | 14400.0 |
| 2024-11-14 10:02:00 | user-3 | 205.0 | 25.0 |
List of related functions
- sqrt: Returns the square root of a value. This is equivalent to
pow(x, 0.5)and is more readable for the square-root case. - exp: Returns e^x. Use it when the base is e rather than an arbitrary number.
- exp2: Returns 2^x. Use it when the base is always 2.
- exp10: Returns 10^x. Use it when the base is always 10.
- log: Returns the natural logarithm. Use it to undo a
powtransformation in log space.