---
title: math.erf() function
description: math.erf() returns the error function of x.
url: https://docs.influxdata.com/flux/v0/stdlib/math/erf/
estimated_tokens: 1367
product: Flux
version: v0
---

# math.erf() function

-   Flux 0.22.0+
-   View InfluxDB support

`math.erf()` returns the error function of `x`.

##### Function type signature

```js
(x: float) => float
```

For more information, see [Function type signatures](/flux/v0/function-type-signatures/).

## Parameters

### x

(Required) Value to operate on.

## Examples

-   [Return the error function of a value.](#return-the-error-function-of-a-value)
-   [Use math.erf in map](#use-matherf-in-map)

### Return the error function of a value.

```js
import "math"

math.erf(x: 22.6)// 1.0

```

### Use math.erf in map

```js
import "math"
import "sampledata"

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

[](#view-example-input-and-output)

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 | -0.9979506490526588 | t1 |
| 2021-01-01T00:00:10Z | 1 | t1 |
| 2021-01-01T00:00:20Z | 1 | t1 |
| 2021-01-01T00:00:30Z | 1 | t1 |
| 2021-01-01T00:00:40Z | 1 | t1 |
| 2021-01-01T00:00:50Z | 0.9999999996270934 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 1 | t2 |
| 2021-01-01T00:00:10Z | 0.9999999999979144 | t2 |
| 2021-01-01T00:00:20Z | -0.9999998862727434 | t2 |
| 2021-01-01T00:00:30Z | 1 | t2 |
| 2021-01-01T00:00:40Z | 1 | t2 |
| 2021-01-01T00:00:50Z | 0.9914724883356396 | t2 |