math.expm1() function

<!------------------------------------------------------------------------------ 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#L827-L827 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

math.expm1() returns e**x - 1, the base-e exponential of x minus 1. It is more accurate than math.exp(x:x) - 1 when x is near zero.

Function type signature

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

Parameters

x

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

Examples

• Get more accurate base-e exponentials for values near zero
• Use math.expm1 in map

Get more accurate base-e exponentials for values near zero

Use math.expm1 in map

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

Input data

_time	*tag	_value
2021-01-01T00:00:00Z	t1	-0.021800000000000003
2021-01-01T00:00:10Z	t1	0.1092
2021-01-01T00:00:20Z	t1	0.0735
2021-01-01T00:00:30Z	t1	0.1753
2021-01-01T00:00:40Z	t1	0.15230000000000002
2021-01-01T00:00:50Z	t1	0.0443

_time	*tag	_value
2021-01-01T00:00:00Z	t2	0.1985
2021-01-01T00:00:10Z	t2	0.0497
2021-01-01T00:00:20Z	t2	-0.0375
2021-01-01T00:00:30Z	t2	0.1977
2021-01-01T00:00:40Z	t2	0.1386
2021-01-01T00:00:50Z	t2	0.018600000000000002

Output data

_time	_value	*tag
2021-01-01T00:00:00Z	-0.02156409733567063	t1
2021-01-01T00:00:10Z	0.11538540511625006	t1
2021-01-01T00:00:20Z	0.07626853667189179	t1
2021-01-01T00:00:30Z	0.1916036440887826	t1
2021-01-01T00:00:40Z	0.16450953689549175	t1
2021-01-01T00:00:50Z	0.045295896623819054	t1

_time	_value	*tag
2021-01-01T00:00:00Z	0.21957202741425103	t2
2021-01-01T00:00:10Z	0.05095576234958021	t2
2021-01-01T00:00:20Z	-0.03680558227917823	t2
2021-01-01T00:00:30Z	0.21859675995131905	t2
2021-01-01T00:00:40Z	0.14866454228127554	t2
2021-01-01T00:00:50Z	0.018774057481622756	t2

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