---
title: doubleEMA() function
description: doubleEMA() returns the double exponential moving average (DEMA) of values in the _value column grouped into n number of points, giving more weight to recent data.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/doubleema/
estimated_tokens: 1453
product: Flux
version: v0
---

# doubleEMA() function

-   Flux 0.38.0+
-   View InfluxDB support

`doubleEMA()` returns the double exponential moving average (DEMA) of values in the `_value` column grouped into `n` number of points, giving more weight to recent data.

#### Double exponential moving average rules

-   A double exponential moving average is defined as `doubleEMA = 2 * EMA_N - EMA of EMA_N`.
    -   `EMA` is an exponential moving average.
    -   `N = n` is the period used to calculate the `EMA`.
-   A true double exponential moving average requires at least `2 * n - 1` values. If not enough values exist to calculate the double `EMA`, it returns a `NaN` value.
-   `doubleEMA()` inherits all `exponentialMovingAverage()` rules.

##### Function type signature

```js
(<-tables: stream[{A with _value: B}], n: int) => stream[C] where B: Numeric, C: Record
```

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

## Parameters

### n

(Required) Number of points to average.

### tables

Input data. Default is piped-forward data (`<-`).

## Examples

### Calculate a three point double exponential moving average

```js
import "sampledata"

sampledata.int()
    |> doubleEMA(n: 3)
```

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

View example input and output

#### Input data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 16.333333333333336 | t1 |
| 2021-01-01T00:00:50Z | 7.916666666666668 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 15.027777777777779 | t2 |
| 2021-01-01T00:00:50Z | 5.034722222222221 | t2 |

#### Related

-   [movingAverage() function](/flux/v0/stdlib/universe/movingaverage/)
-   [tripleEMA() function](/flux/v0/stdlib/universe/tripleema/)
-   [timedMovingAverage() function](/flux/v0/stdlib/universe/timedmovingaverage/)
-   [exponentialMovingAverage() function](/flux/v0/stdlib/universe/exponentialmovingaverage/)
-   [InfluxQL DOUBLE\_EXPONENTIAL\_MOVING\_AVERAGE()](/influxdb/v1/query_language/functions/#double-exponential-moving-average)

[transformations](/flux/v0/tags/transformations/)