cbrt ↗

Use the cbrt() function to calculate the cube root of a numeric value.

Syntax

cbrt(<number>)

Parameters

Name Type Required Description
number integer, float Yes The numeric value for which to calculate the cube root. Any real number is valid, including negative numbers.

Returns

Type: float

Description: The cbrt() function returns the cube root of the input value. If the input is null, the function returns null.

Usage notes

  • Input type: XQL doesn't support NaN or infinite values as input and these value types also can not be returned.
  • Valid Input Range: The cbrt() function accepts any real number, including negative numbers and zero.
  • Null Handling: If the input expression is null, the function returns null.
  • Negative Numbers: Unlike square root (sqrt()), the cube root of a negative number is a valid real number. For example, cbrt(-8) returns -2.0.
  • Identity Values: cbrt(0) returns 0.0, cbrt(1) returns 1.0, and cbrt(-1) returns -1.0.
  • Common Use Cases: This function is typically used within the alter stage for mathematical transformations, volume calculations, and data normalization.

Examples

Example 1: Calculate cube root of literal values

Goal: Calculate the cube root for specific numeric literals to verify known mathematical results.

XQL code:

dataset = xdr_data
| limit 1
| alter result1 = cbrt(8), result2 = cbrt(27), result3 = cbrt(-8)
| fields result1, result2, result3

Explanation: You use cbrt() on three different literal values. cbrt(8) returns 2.0, cbrt(27) returns 3.0, and cbrt(-8) returns -2.0, demonstrating that the function handles negative inputs correctly.

Output:

RESULT1 RESULT2 RESULT3
2.0 3.0 -2.0

Example 2: Calculate cube root from a field value

Goal: Calculate the cube root of values stored in a dataset field.

XQL code:

config timeframe = 1d
| dataset = sample_xql_raw
| alter cube_root_val = cbrt(numeric_value)
| fields event_id, numeric_value, cube_root_val
| limit 3

Explanation: This query computes the cube root for each value in the numeric_value field using cbrt() in the alter stage and stores the result in cube_root_val. No filtering is needed since cbrt() accepts any real number.

Output:

EVENT_ID NUMERIC_VALUE CUBE_ROOT_VAL
101 125.0 5.0
102 -27.0 -3.0
103 1000.0 10.0

Example 3: Combine cube root with other operations

Goal: Use the cube root function as part of a larger mathematical expression.

XQL code:

config timeframe = 1d
| dataset = sample_xql_raw
| alter volume = multiply(numeric_value, multiply(numeric_value, numeric_value))
| alter side_length = cbrt(volume)
| fields event_id, numeric_value, volume, side_length
| limit 3

Explanation: This query first cubes the numeric_value to simulate a volume, then applies cbrt() to recover the original side length. The result in side_length should match the original numeric_value, demonstrating that cbrt() is the inverse of cubing.

Output:

EVENT_ID NUMERIC_VALUE VOLUME SIDE_LENGTH
101 3.0 27.0 3.0
102 5.0 125.0 5.0
103 10.0 1000.0 10.0