integral() function

The integral() function computes the area under the curve per unit of time of subsequent non-null records. integral() requires _start and _stop columns that are part of the group key. The curve is defined using _time as the domain and record values as the range. integral() is an aggregate function.

Output data type: Float

integral(
  unit: 10s,
  column: "_value",
  timeColumn: "_time",
  interpolate: ""
)

Parameters

unit

(Required) Time duration used when computing the integral.

column

Column on which to operate. Defaults to "_value".

timeColumn

Column that contains time values to use in the operation. Defaults to "_time".

interpolate

Type of interpolation to use. Defaults to "".

Use one of the following interpolation options:

• empty string for no interpolation
• linear

tables

Input data. Default is piped-forward data (<-).

Examples

The following examples use data provided by the sampledata package to show how integral() transforms data.

Calculate the integral

import "sampledata"

sampledata.int()
  |> range(start: sampledata.start, stop: sampledata.stop)
  |> integral(unit:10s)

Calculate the integral with linear interpolation

import "sampledata"

sampledata.int(includeNull: true)
  |> range(start: sampledata.start, stop: sampledata.stop)
  |> integral(unit:10s, interpolate: "linear")