182 lines
6.2 KiB
Markdown
182 lines
6.2 KiB
Markdown
---
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title: integral() function
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description: >
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`integral()` computes the area under the curve per unit of time of subsequent non-null records.
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menu:
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flux_v0_ref:
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name: integral
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parent: universe
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identifier: universe/integral
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weight: 101
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flux/v0/tags: [transformations, aggregates]
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introduced: 0.7.0
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---
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<!------------------------------------------------------------------------------
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IMPORTANT: This page was generated from comments in the Flux source code. Any
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edits made directly to this page will be overwritten the next time the
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documentation is generated.
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To make updates to this documentation, update the function comments above the
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function definition in the Flux source code:
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https://github.com/influxdata/flux/blob/master/stdlib/universe/universe.flux#L1101-L1110
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Contributing to Flux: https://github.com/influxdata/flux#contributing
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Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md
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------------------------------------------------------------------------------->
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`integral()` computes the area under the curve per unit of time of subsequent non-null records.
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`integral()` requires `_start` and `_stop` columns that are part of the group key.
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The curve is defined using `_time` as the domain and record values as the range.
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##### Function type signature
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```js
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(
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<-tables: stream[A],
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?column: string,
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?interpolate: string,
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?timeColumn: string,
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?unit: duration,
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) => stream[B] where A: Record, B: Record
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```
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{{% caption %}}
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For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
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{{% /caption %}}
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## Parameters
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### unit
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Unit of time to use to compute the integral.
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### column
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Column to operate on. Default is `_value`.
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### timeColumn
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Column that contains time values to use in the operation.
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Default is `_time`.
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### interpolate
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Type of interpolation to use. Default is `""`.
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**Available interplation types**:
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- linear
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- _empty string for no interpolation_
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### tables
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Input data. Default is piped-forward data (`<-`).
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## Examples
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- [Calculate the integral](#calculate-the-integral)
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- [Calculate the integral with linear interpolation](#calculate-the-integral-with-linear-interpolation)
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### Calculate the integral
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```js
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data
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|> integral(unit: 10s)
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```
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{{< expand-wrapper >}}
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{{% expand "View example input and output" %}}
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#### Input data
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| *_start | *_stop | _time | _value | *tag |
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| -------------------- | -------------------- | -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 10 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |
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| *_start | *_stop | _time | _value | *tag |
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| -------------------- | -------------------- | -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 19 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 4 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | -3 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |
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#### Output data
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| *_start | *_stop | *tag | _value |
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| -------------------- | -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | t1 | 50 |
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| *_start | *_stop | *tag | _value |
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| -------------------- | -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | t2 | 43 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### Calculate the integral with linear interpolation
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```js
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data
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|> integral(unit: 10s, interpolate: "linear")
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```
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{{< expand-wrapper >}}
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{{% expand "View example input and output" %}}
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#### Input data
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| *_start | *_stop | _time | _value | *tag |
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| -------------------- | -------------------- | -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | | t1 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |
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| *_start | *_stop | _time | _value | *tag |
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| -------------------- | -------------------- | -------------------- | ------- | ---- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 4 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | -3 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | | t2 |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |
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#### Output data
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| *_start | *_stop | *tag | _value |
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| -------------------- | -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | t1 | 25 |
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| *_start | *_stop | *tag | _value |
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| -------------------- | -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | t2 | 32.5 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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