125 lines
3.2 KiB
Markdown
125 lines
3.2 KiB
Markdown
---
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title: math.exp2() function
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description: >
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`math.exp2()` returns `2**x`, the base-2 exponential of `x`.
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menu:
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flux_v0_ref:
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name: math.exp2
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parent: math
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identifier: math/exp2
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weight: 101
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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/math/math.flux#L789-L789
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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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`math.exp2()` returns `2**x`, the base-2 exponential of `x`.
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##### Function type signature
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```js
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(x: float) => float
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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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### x
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({{< req >}})
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Value to operate on.
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## Examples
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- [Return the base-2 exponential of a value](#return-the-base-2-exponential-of-a-value)
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- [Use math.exp2 in map](#use-mathexp2-in-map)
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### Return the base-2 exponential of a value
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```js
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import "math"
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math.exp2(x: 21.0)// 2.097152e+06
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```
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### Use math.exp2 in map
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```js
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import "sampledata"
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import "math"
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sampledata.float()
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|> map(fn: (r) => ({r with _value: math.exp2(x: r._value)}))
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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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| _time | *tag | _value |
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| -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | t1 | -2.18 |
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| 2021-01-01T00:00:10Z | t1 | 10.92 |
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| 2021-01-01T00:00:20Z | t1 | 7.35 |
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| 2021-01-01T00:00:30Z | t1 | 17.53 |
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| 2021-01-01T00:00:40Z | t1 | 15.23 |
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| 2021-01-01T00:00:50Z | t1 | 4.43 |
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| _time | *tag | _value |
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| -------------------- | ---- | ------- |
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| 2021-01-01T00:00:00Z | t2 | 19.85 |
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| 2021-01-01T00:00:10Z | t2 | 4.97 |
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| 2021-01-01T00:00:20Z | t2 | -3.75 |
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| 2021-01-01T00:00:30Z | t2 | 19.77 |
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| 2021-01-01T00:00:40Z | t2 | 13.86 |
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| 2021-01-01T00:00:50Z | t2 | 1.86 |
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#### Output data
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| _time | _value | *tag |
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| -------------------- | ------------------- | ---- |
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| 2021-01-01T00:00:00Z | 0.22067574907266369 | t1 |
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| 2021-01-01T00:00:10Z | 1937.5260604940204 | t1 |
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| 2021-01-01T00:00:20Z | 163.1437602968655 | t1 |
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| 2021-01-01T00:00:30Z | 189258.68751552477 | t1 |
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| 2021-01-01T00:00:40Z | 38431.45561643022 | t1 |
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| 2021-01-01T00:00:50Z | 21.55573722985104 | t1 |
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| _time | _value | *tag |
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| -------------------- | ------------------- | ---- |
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| 2021-01-01T00:00:00Z | 945029.6050826148 | t2 |
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| 2021-01-01T00:00:10Z | 31.341449522781655 | t2 |
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| 2021-01-01T00:00:20Z | 0.07432544468767006 | t2 |
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| 2021-01-01T00:00:30Z | 894052.4842704767 | t2 |
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| 2021-01-01T00:00:40Z | 14868.793840716358 | t2 |
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| 2021-01-01T00:00:50Z | 3.6300766212686435 | t2 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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