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math.j1() function

content/flux/v0/stdlib/math/j1.md

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<!------------------------------------------------------------------------------ IMPORTANT: This page was generated from comments in the Flux source code. Any edits made directly to this page will be overwritten the next time the documentation is generated. To make updates to this documentation, update the function comments above the function definition in the Flux source code: https://github.com/influxdata/flux/blob/master/stdlib/math/math.flux#L1224-L1224 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

math.j1() is a function that returns the order-one Bessel function for the first kind.

Function type signature
js
(x: float) => float

{{% caption %}} For more information, see Function type signatures. {{% /caption %}}

Parameters

x

({{< req >}}) Value to operate on.

Examples

Return the order-one Bessel function of a value

js
import "math"

math.j1(x: 1.23)// 0.5058005726280961

Use math.j1 in map

js
import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.j1(x: r._value)}))

{{< expand-wrapper >}} {{% expand "View example input and output" %}}

Input data

_time*tag_value
2021-01-01T00:00:00Zt1-2.18
2021-01-01T00:00:10Zt110.92
2021-01-01T00:00:20Zt17.35
2021-01-01T00:00:30Zt117.53
2021-01-01T00:00:40Zt115.23
2021-01-01T00:00:50Zt14.43
_time*tag_value
2021-01-01T00:00:00Zt219.85
2021-01-01T00:00:10Zt24.97
2021-01-01T00:00:20Zt2-3.75
2021-01-01T00:00:30Zt219.77
2021-01-01T00:00:40Zt213.86
2021-01-01T00:00:50Zt21.86

Output data

_time_value*tag
2021-01-01T00:00:00Z-0.5587345375771166t1
2021-01-01T00:00:10Z-0.16378152627369913t1
2021-01-01T00:00:20Z0.096261851305172t1
2021-01-01T00:00:30Z-0.16615705227678823t1
2021-01-01T00:00:40Z0.19344160659360385t1
2021-01-01T00:00:50Z-0.21154289673897086t1
_time_value*tag
2021-01-01T00:00:00Z0.041529757669801666t2
2021-01-01T00:00:10Z-0.3240653024080138t2
2021-01-01T00:00:20Z-0.03322934912967974t2
2021-01-01T00:00:30Z0.027537686650143067t2
2021-01-01T00:00:40Z0.10941596518105894t2
2021-01-01T00:00:50Z0.5817926469097867t2

{{% /expand %}} {{< /expand-wrapper >}}