content/flux/v0/stdlib/universe/doubleema.md
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.
doubleEMA = 2 * EMA_N - EMA of EMA_N.
EMA is an exponential moving average.N = n is the period used to calculate the EMA.2 * n - 1 values.
If not enough values exist to calculate the double EMA, it returns a NaN value.doubleEMA() inherits all exponentialMovingAverage() rules.(<-tables: stream[{A with _value: B}], n: int) => stream[C] where B: Numeric, C: Record
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({{< req >}}) Number of points to average.
Input data. Default is piped-forward data (<-).
import "sampledata"
sampledata.int()
|> doubleEMA(n: 3)
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| _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 |
| _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 |
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