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math.jn() function

content/flux/v0/stdlib/math/jn.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#L1257-L1257 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

math.jn() returns the order-n Bessel function of the first kind.

Function type signature
js
(n: int, x: float) => float

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

Parameters

n

({{< req >}}) Order number.

x

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

Examples

Return the order-n Bessel function of a value

js
import "math"

math.jn(n: 2, x: 1.23)// 0.16636938378681407

Use math.jn in map

js
import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.jn(n: 4, 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
2021-01-01T00:00:00Z0.046148335742456664t1
2021-01-01T00:00:10Z-0.03367382202216673t1
2021-01-01T00:00:20Z0.06455053599079605t1
2021-01-01T00:00:30Z-0.016152633110842446t1
2021-01-01T00:00:40Z-0.15300380439231542t1
2021-01-01T00:00:50Z0.3401384178914538t1
_time_value*tag
2021-01-01T00:00:00Z0.14801732445932958t2
2021-01-01T00:00:10Z0.3896093468299793t2
2021-01-01T00:00:20Z0.24301709268606153t2
2021-01-01T00:00:30Z0.15603599253486927t2
2021-01-01T00:00:40Z0.10341672446511223t2
2021-01-01T00:00:50Z0.026150267042506597t2

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