docs-v2/content/flux/v0/stdlib/math/y0.md

title	description	menu	weight
math.y0() function	`math.y0()` returns the order-zero Bessel function of the second kind.	flux_v0_ref name parent identifier math.y0 math math/y0	101

math.y0() returns the order-zero Bessel function of the second kind.

Function type signature

(x: float) => float

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

Parameters

x

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

Examples

• Return the order-zero Bessel function of a value
• Use math.y0 in map

Return the order-zero Bessel function of a value

import "math"

math.y0(x: 3.14)// 0.3289375969127807

Use math.y0 in map

import "math"
import "sampledata"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.y0(x: r._value)}))

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

Input data

_time	*tag	_value
2021-01-01T00:00:00Z	t1	-2.18
2021-01-01T00:00:10Z	t1	10.92
2021-01-01T00:00:20Z	t1	7.35
2021-01-01T00:00:30Z	t1	17.53
2021-01-01T00:00:40Z	t1	15.23
2021-01-01T00:00:50Z	t1	4.43

_time	*tag	_value
2021-01-01T00:00:00Z	t2	19.85
2021-01-01T00:00:10Z	t2	4.97
2021-01-01T00:00:20Z	t2	-3.75
2021-01-01T00:00:30Z	t2	19.77
2021-01-01T00:00:40Z	t2	13.86
2021-01-01T00:00:50Z	t2	1.86

Output data

_time	_value	*tag
2021-01-01T00:00:00Z	NaN	t1
2021-01-01T00:00:10Z	-0.15517570189175475	t1
2021-01-01T00:00:20Z	0.07687091351245329	t1
2021-01-01T00:00:30Z	-0.16329326302215585	t1
2021-01-01T00:00:40Z	0.19531314382470338	t1
2021-01-01T00:00:50Z	-0.17300760424559283	t1

_time	_value	*tag
2021-01-01T00:00:00Z	0.03710847827981653	t2
2021-01-01T00:00:10Z	-0.3039299357361664	t2
2021-01-01T00:00:20Z	NaN	t2
2021-01-01T00:00:30Z	0.023033101962350977	t2
2021-01-01T00:00:40Z	0.10257274599514705	t2
2021-01-01T00:00:50Z	0.4897750655109666	t2

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