diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow.md
index c82f5ee3b..5127800f3 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow.md
@@ -10,7 +10,8 @@ menu:
weight: 501
---
-The `aggregateWindow()` function applies an aggregate function to fixed windows of time.
+The `aggregateWindow()` function applies an aggregate or selector function
+(any function with a `column` parameter) to fixed windows of time.
_**Function type:** Aggregate_
@@ -25,7 +26,7 @@ aggregateWindow(
)
```
-As data is windowed into separate tables and aggregated, the `_time` column is dropped from each group key.
+As data is windowed into separate tables and processed, the `_time` column is dropped from each group key.
This function copies the timestamp from a remaining column into the `_time` column.
View the [function definition](#function-definition).
@@ -42,7 +43,7 @@ The [aggregate function](/v2.0/reference/flux/functions/built-in/transformations
_**Data type:** Function_
{{% note %}}
-Only aggregate functions with a `column` parameter (singular) work with `aggregateWindow()`.
+Only aggregate and selector functions with a `column` parameter (singular) work with `aggregateWindow()`.
{{% /note %}}
### column
@@ -84,10 +85,10 @@ from(bucket: "example-bucket")
fn: mean
)
```
-###### Specifying parameters of the aggregate function
-To use `aggregateWindow()` aggregate functions that don't provide defaults for required parameters,
-for the `fn` parameter, define an anonymous function with `columns` and `tables` parameters
-that pipe-forwards tables into the aggregate function with all required parameters defined:
+###### Specify parameters of the aggregate function
+To use functions that don't provide defaults for required parameters with `aggregateWindow()`,
+define an anonymous function with `column` and `tables` parameters that pipe-forward
+tables into the aggregate or selector function with all required parameters defined:
```js
from(bucket: "example-bucket")
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/difference.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/difference.md
index f864f6626..3e52efdba 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/difference.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/difference.md
@@ -17,7 +17,11 @@ _**Function type:** Aggregate_
_**Output data type:** Float_
```js
-difference(nonNegative: false, column: "_value")
+difference(
+ nonNegative: false,
+ column: "_value",
+ keepFirst: false
+)
```
## Parameters
@@ -34,6 +38,13 @@ Defaults to `"_value"`.
_**Data type:** String_
+### keepFirst
+Indicates the first row should be kept.
+If `true`, the difference will be `null`.
+Defaults to `false`.
+
+_**Data type:** Boolean_
+
## Subtraction rules for numeric types
- The difference between two non-null values is their algebraic difference;
or `null`, if the result is negative and `nonNegative: true`;
@@ -90,6 +101,20 @@ from(bucket: "example-bucket")
| 0004 | 6 | tv |
| 0005 | null | tv |
+
+#### With keepFirst set to true
+```js
+|> difference(nonNegative: false, keepfirst: true):
+```
+###### Output table
+| _time | _value | tag |
+|:-----:|:------:|:---:|
+| 0001 | null | tv |
+| 0002 | null | tv |
+| 0003 | -2 | tv |
+| 0004 | 6 | tv |
+| 0005 | null | tv |
+
##### Related InfluxQL functions and statements:
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema.md
new file mode 100644
index 000000000..88a99ef58
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema.md
@@ -0,0 +1,63 @@
+---
+title: doubleEMA() function
+description: >
+ The `doubleEMA()` function calculates the exponential moving average of values
+ grouped into `n` number of points, giving more weight to recent data at double
+ the rate of `exponentialMovingAverage()`.
+menu:
+ v2_0_ref:
+ name: doubleEMA
+ parent: built-in-aggregates
+weight: 501
+related:
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/
+ - https://docs.influxdata.com/influxdb/v1.7/query_language/functions/#double-exponential-moving-average, InfluxQL DOUBLE_EXPONENTIAL_MOVING_AVERAGE()
+---
+
+The `doubleEMA()` function calculates the exponential moving average of values in
+the `_value` column grouped into `n` number of points, giving more weight to recent
+data at double the rate of [`exponentialMovingAverage()`](/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/).
+
+_**Function type:** Aggregate_
+
+```js
+doubleEMA(n: 5)
+```
+
+##### 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 [exponential moving average rules](/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/#exponential-moving-average-rules).
+
+## Parameters
+
+### n
+The number of points to average.
+
+_**Data type:** Integer_
+
+## Examples
+
+#### Calculate a five point double exponential moving average
+```js
+from(bucket: "example-bucket"):
+ |> range(start: -12h)
+ |> doubleEMA(n: 5)
+```
+
+## Function definition
+```js
+doubleEMA = (n, tables=<-) =>
+ tables
+ |> exponentialMovingAverage(n:n)
+ |> duplicate(column:"_value", as:"ema")
+ |> exponentialMovingAverage(n:n)
+ |> map(fn: (r) => ({r with _value: 2.0 * r.ema - r._value}))
+ |> drop(columns: ["ema"])
+```
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage.md
index da132b4ab..c543ab342 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage.md
@@ -1,8 +1,8 @@
---
title: exponentialMovingAverage() function
description: >
- The `exponentialMovingAverage()` function calculates the exponential moving average
- of values grouped into `n` number of points, giving more weight to recent data.
+ The `exponentialMovingAverage()` function calculates the exponential moving average of values
+ in the `_value` column grouped into `n` number of points, giving more weight to recent data.
menu:
v2_0_ref:
name: exponentialMovingAverage
@@ -11,22 +11,21 @@ weight: 501
related:
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage/
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema/
- https://docs.influxdata.com/influxdb/v1.7/query_language/functions/#exponential-moving-average, InfluxQL EXPONENTIAL_MOVING_AVERAGE()
---
-The `exponentialMovingAverage()` function calculates the exponential moving average
-of values grouped into `n` number of points, giving more weight to recent data.
+The `exponentialMovingAverage()` function calculates the exponential moving average of values
+in the `_value` column grouped into `n` number of points, giving more weight to recent data.
_**Function type:** Aggregate_
```js
-exponentialMovingAverage(
- n: 5,
- columns: ["_value"]
-)
+exponentialMovingAverage(n: 5)
```
-##### Exponential moving average rules:
+##### Exponential moving average rules
- The first value of an exponential moving average over `n` values is the
algebraic mean of `n` values.
- Subsequent values are calculated as `y(t) = x(t) * k + y(t-1) * (1 - k)`, where:
@@ -43,11 +42,6 @@ The number of points to average.
_**Data type:** Integer_
-### columns
-Columns to operate on. _Defaults to `["_value"]`_.
-
-_**Data type:** Array of Strings_
-
## Examples
#### Calculate a five point exponential moving average
@@ -60,23 +54,20 @@ from(bucket: "example-bucket"):
#### Table transformation with a two point exponential moving average
###### Input table:
-| _time | A | B | C | tag |
-|:-----:|:----:|:----:|:----:|:---:|
-| 0001 | 2 | null | 2 | tv |
-| 0002 | null | 10 | 4 | tv |
-| 0003 | 8 | 20 | 5 | tv |
+| _time | tag | _value |
+|:-----:|:---:|:------:|
+| 0001 | tv | null |
+| 0002 | tv | 10 |
+| 0003 | tv | 20 |
###### Query:
```js
// ...
- |> exponentialMovingAverage(
- n: 2,
- columns: ["A", "B", "C"]
- )
+ |> exponentialMovingAverage(n: 2)
```
###### Output table:
-| _time | A | B | C | tag |
-|:-----:|:----:|:----:|:----:|:---:|
-| 0002 | 2 | 10 | 3 | tv |
-| 0003 | 6 | 16.67| 4.33 | tv |
+| _time | tag | _value |
+|:-----:|:---:|:------:|
+| 0002 | tv | 10 |
+| 0003 | tv | 16.67 |
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/holtwinters.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/holtwinters.md
new file mode 100644
index 000000000..7301ce089
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/holtwinters.md
@@ -0,0 +1,114 @@
+---
+title: holtWinters() function
+description: >
+ The `holtWinters()` function applies the Holt-Winters forecasting method to input tables.
+aliases:
+ - /v2.0/reference/flux/functions/transformations/aggregates/holtwinters
+menu:
+ v2_0_ref:
+ name: holtWinters
+ parent: built-in-aggregates
+weight: 501
+related:
+ - https://docs.influxdata.com/influxdb/latest/query_language/functions/#holt-winters, InfluxQL HOLT_WINTERS()
+---
+
+The `holtWinters()` function applies the Holt-Winters forecasting method to input tables.
+
+_**Function type:** Aggregate_
+_**Output data type:** Float_
+
+```js
+holtWinters(
+ n: 10,
+ seasonality: 4,
+ interval: 30d,
+ withFit: false,
+ timeColumn: "_time",
+ column: "_value",
+)
+```
+
+The Holt-Winters method predicts [`n`](#n) seasonally-adjusted values for the
+specified [`column`](#column) at the specified [`interval`](#interval).
+For example, if `interval` is `6m` and `n` is `3`, results include three predicted
+values six minutes apart.
+
+#### Seasonality
+[`seasonality`](#seasonality) delimits the length of a seasonal pattern according to `interval`.
+If your `interval` is `2m` and `seasonality` is `4`, then the seasonal pattern occurs every
+eight minutes or every four data points.
+If data doesn't have a seasonal pattern, set `seasonality` to `0`.
+
+#### Space values evenly in time
+`holtWinters()` expects values evenly spaced in time.
+To ensure `holtWinters()` values are spaced evenly in time, the following rules apply:
+
+- Data is grouped into time-based "buckets" determined by the `interval`.
+- If a bucket includes many values, the first value is used.
+- If a bucket includes no values, a missing value (`null`) is added for that bucket.
+
+By default, `holtWinters()` uses the first value in each time bucket to run the Holt-Winters calculation.
+To specify other values to use in the calculation, use:
+
+- [`window()`](/v2.0/reference/flux/functions/built-in/transformations/window/)
+ with [selectors](/v2.0/reference/flux/functions/built-in/transformations/selectors/)
+ or [aggregates](/v2.0/reference/flux/functions/built-in/transformations/aggregates/)
+- [`aggregateWindow()`](/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow)
+
+#### Fitted model
+The `holtWinters()` function applies the [Nelder-Mead optimization](https://en.wikipedia.org/wiki/Nelder%E2%80%93Mead_method)
+to include "fitted" data points in results when [`withFit`](#withfit) is set to `true`.
+
+#### Null timestamps
+`holtWinters()` discards rows with `null` timestamps before running the Holt-Winters calculation.
+
+#### Null values
+`holtWinters()` treats `null` values as missing data points and includes them in the Holt-Winters calculation.
+
+## Parameters
+
+### n
+The number of values to predict.
+
+_**Data type: Integer**_
+
+### seasonality
+The number of points in a season.
+Defaults to `0`.
+
+_**Data type: Integer**_
+
+### interval
+The interval between two data points.
+
+_**Data type: Duration**_
+
+### withFit
+Return [fitted data](#fitted-model) in results.
+Defaults to `false`.
+
+_**Data type: Boolean**_
+
+### timeColumn
+The time column to use.
+Defaults to `"_time"`.
+
+_**Data type: String**_
+
+### column
+The column to operate on.
+Defaults to `"_value"`.
+
+_**Data type: String**_
+
+## Examples
+
+##### Use aggregateWindow to prepare data for holtWinters
+```js
+from(bucket: "example-bucket")
+ |> range(start: -7y)
+ |> filter(fn: (r) => r._field == "water_level")
+ |> aggregateWindow(every: 379m, fn: first).
+ |> holtWinters(n: 10, seasonality: 4, interval: 379m)
+```
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage.md
index ee4687b40..3ee8221c2 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage.md
@@ -10,21 +10,21 @@ weight: 501
related:
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage/
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema/
- https://docs.influxdata.com/influxdb/latest/query_language/functions/#moving-average, InfluxQL MOVING_AVERAGE()
---
-The `movingAverage()` function calculates the mean of values grouped into `n` number of points.
+The `movingAverage()` function calculates the mean of values in the `_values` column
+grouped into `n` number of points.
_**Function type:** Aggregate_
```js
-movingAverage(
- n: 5,
- columns: ["_value"]
-)
+movingAverage(n: 5)
```
-##### Moving average rules:
+##### Moving average rules
- The average over a period populated by `n` values is equal to their algebraic mean.
- The average over a period populated by only `null` values is `null`.
- Moving averages skip `null` values.
@@ -38,11 +38,6 @@ The number of points to average.
_**Data type:** Integer_
-### columns
-Columns to operate on. _Defaults to `["_value"]`_.
-
-_**Data type:** Array of Strings_
-
## Examples
#### Calculate a five point moving average
@@ -52,36 +47,23 @@ from(bucket: "example-bucket"):
|> movingAverage(n: 5)
```
-#### Calculate a ten point moving average
-```js
-movingAverage = (every, period, column="_value", tables=<-) =>
- tables
- |> window(every: every, period: period)
- |> mean(column: column)
- |> duplicate(column: "_stop", as: "_time")
- |> window(every: inf)
-```
-
#### Table transformation with a two point moving average
###### Input table:
-| _time | A | B | C | D | tag |
-|:-----:|:----:|:----:|:----:|:----:|:---:|
-| 0001 | null | 1 | 2 | null | tv |
-| 0002 | 6 | 2 | null | null | tv |
-| 0003 | 4 | null | 4 | 4 | tv |
+| _time | tag | _value |
+|:-----:|:---:|:------:|
+| 0001 | tv | null |
+| 0002 | tv | 6 |
+| 0003 | tv | 4 |
###### Query:
```js
// ...
- |> movingAverage(
- n: 2,
- columns: ["A", "B", "C", "D"]
- )
+ |> movingAverage(n: 2 )
```
###### Output table:
-| _time | A | B | C | D | tag |
-|:-----:|:----:|:----:|:----:|:----:|:---:|
-| 0002 | 6 | 1.5 | 2 | null | tv |
-| 0003 | 5 | 2 | 4 | 4 | tv |
+| _time | tag | _value |
+|:-----:|:---:|:------:|
+| 0002 | tv | 6 |
+| 0003 | tv | 5 |
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/relativestrengthindex.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/relativestrengthindex.md
new file mode 100644
index 000000000..d8f08460b
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/relativestrengthindex.md
@@ -0,0 +1,103 @@
+---
+title: relativeStrengthIndex() function
+description: >
+ The `relativeStrengthIndex()` function measures the relative speed and change of
+ values in an input table.
+menu:
+ v2_0_ref:
+ name: relativeStrengthIndex
+ parent: built-in-aggregates
+weight: 501
+related:
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/
+ - https://docs.influxdata.com/influxdb/v1.7/query_language/functions/#relative-strength-index, InfluxQL RELATIVE_STRENGTH_INDEX()
+---
+
+The `relativeStrengthIndex()` function measures the relative speed and change of
+values in an input table.
+
+_**Function type:** Aggregate_
+
+```js
+relativeStrengthIndex(
+ n: 5,
+ columns: ["_value"]
+)
+```
+
+##### Relative strength index rules
+- The general equation for calculating a relative strength index (RSI) is
+ `RSI = 100 - (100 / (1 + (AVG GAIN / AVG LOSS)))`.
+- For the first value of the RSI, `AVG GAIN` and `AVG LOSS` are averages of the `n` period.
+- For subsequent calculations:
+ - `AVG GAIN` = `((PREVIOUS AVG GAIN) * (n - 1)) / n`
+ - `AVG LOSS` = `((PREVIOUS AVG LOSS) * (n - 1)) / n`
+- `relativeStrengthIndex()` ignores `null` values.
+
+## Parameters
+
+### n
+The number of values to use to calculate the RSI.
+
+_**Data type:** Integer_
+
+### columns
+Columns to operate on. _Defaults to `["_value"]`_.
+
+_**Data type:** Array of Strings_
+
+## Examples
+
+#### Calculate a five point relative strength index
+```js
+from(bucket: "example-bucket"):
+ |> range(start: -12h)
+ |> relativeStrengthIndex(n: 5)
+```
+
+#### Table transformation with a ten point RSI
+
+###### Input table:
+| _time | A | B | tag |
+|:-----:|:----:|:----:|:---:|
+| 0001 | 1 | 1 | tv |
+| 0002 | 2 | 2 | tv |
+| 0003 | 3 | 3 | tv |
+| 0004 | 4 | 4 | tv |
+| 0005 | 5 | 5 | tv |
+| 0006 | 6 | 6 | tv |
+| 0007 | 7 | 7 | tv |
+| 0008 | 8 | 8 | tv |
+| 0009 | 9 | 9 | tv |
+| 0010 | 10 | 10 | tv |
+| 0011 | 11 | 11 | tv |
+| 0012 | 12 | 12 | tv |
+| 0013 | 13 | 13 | tv |
+| 0014 | 14 | 14 | tv |
+| 0015 | 15 | 15 | tv |
+| 0016 | 16 | 16 | tv |
+| 0017 | 17 | null | tv |
+| 0018 | 18 | 17 | tv |
+
+###### Query:
+```js
+// ...
+ |> relativeStrengthIndex(
+ n: 10,
+ columns: ["A", "B"]
+ )
+```
+
+###### Output table:
+| _time | A | B | tag |
+|:-----:|:----:|:----:|:---:|
+| 0011 | 100 | 100 | tv |
+| 0012 | 100 | 100 | tv |
+| 0013 | 100 | 100 | tv |
+| 0014 | 100 | 100 | tv |
+| 0015 | 100 | 100 | tv |
+| 0016 | 90 | 90 | tv |
+| 0017 | 81 | 90 | tv |
+| 0018 | 72.9 | 81 | tv |
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage.md
index 8aa33b397..d9b435213 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage.md
@@ -11,6 +11,8 @@ weight: 501
related:
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage/
- /v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema/
- https://docs.influxdata.com/influxdb/latest/query_language/functions/#moving-average, InfluxQL MOVING_AVERAGE()
---
diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema.md b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema.md
new file mode 100644
index 000000000..cb084a607
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/aggregates/tripleema.md
@@ -0,0 +1,68 @@
+---
+title: tripleEMA() function
+description: >
+ The `tripleEMA()` function calculates the exponential moving average of values
+ grouped into `n` number of points, giving more weight to recent data with less lag
+ than `exponentialMovingAverage()` and `doubleEMA()`.
+menu:
+ v2_0_ref:
+ name: tripleEMA
+ parent: built-in-aggregates
+weight: 501
+related:
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/movingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/timedmovingaverage/
+ - /v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/
+ - https://docs.influxdata.com/influxdb/v1.7/query_language/functions/#triple-exponential-moving-average, InfluxQL TRIPLE_EXPONENTIAL_MOVING_AVERAGE()
+---
+
+The `tripleEMA()` function calculates the exponential moving average of values in
+the `_value` column grouped into `n` number of points, giving more weight to recent
+data with less lag than
+[`exponentialMovingAverage()`](/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/)
+and [`doubleEMA()`](/v2.0/reference/flux/functions/built-in/transformations/aggregates/doubleema/).
+
+_**Function type:** Aggregate_
+
+```js
+tripleEMA(n: 5)
+```
+
+##### Triple exponential moving average rules
+- A triple exponential moving average is defined as `tripleEMA = (3 * EMA_1) - (3 * EMA_2) + EMA_3`.
+ - `EMA_1` is the exponential moving average of the original data.
+ - `EMA_2` is the exponential moving average of `EMA_1`.
+ - `EMA_3` is the exponential moving average of `EMA_2`.
+- A true triple exponential moving average requires at least requires at least `3 * n - 2` values.
+ If not enough values exist to calculate the triple EMA, it returns a `NaN` value.
+- `tripleEMA()` inherits all [exponential moving average rules](/v2.0/reference/flux/functions/built-in/transformations/aggregates/exponentialmovingaverage/#exponential-moving-average-rules).
+
+## Parameters
+
+### n
+The number of points to average.
+
+_**Data type:** Integer_
+
+## Examples
+
+#### Calculate a five point triple exponential moving average
+```js
+from(bucket: "example-bucket"):
+ |> range(start: -12h)
+ |> tripleEMA(n: 5)
+```
+
+## Function definition
+```js
+tripleEMA = (n, tables=<-) =>
+ tables
+ |> exponentialMovingAverage(n:n)
+ |> duplicate(column:"_value", as:"ema1")
+ |> exponentialMovingAverage(n:n)
+ |> duplicate(column:"_value", as:"ema2")
+ |> exponentialMovingAverage(n:n)
+ |> map(fn: (r) => ({r with _value: 3.0 * r.ema1 - 3.0 * r.ema2 + r._value}))
+ |> drop(columns: ["ema1", "ema2"])
+```
diff --git a/content/v2.0/reference/flux/functions/date/microsecond.md b/content/v2.0/reference/flux/functions/date/microsecond.md
new file mode 100644
index 000000000..6a1226250
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/microsecond.md
@@ -0,0 +1,31 @@
+---
+title: date.microsecond() function
+description: >
+ The `date.microsecond()` function returns the microsecond of a specified time.
+ Results range from `[0-999999]`.
+menu:
+ v2_0_ref:
+ name: date.microsecond
+ parent: Date
+weight: 301
+---
+
+The `date.microsecond()` function returns the microsecond of a specified time.
+Results range from `[0-999999]`.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.microsecond(t: 2019-07-17T12:05:21.012934584Z)
+
+// Returns 12934
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/date/millisecond.md b/content/v2.0/reference/flux/functions/date/millisecond.md
new file mode 100644
index 000000000..cc3645240
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/millisecond.md
@@ -0,0 +1,31 @@
+---
+title: date.millisecond() function
+description: >
+ The `date.millisecond()` function returns the millisecond of a specified time.
+ Results range from `[0-999999]`.
+menu:
+ v2_0_ref:
+ name: date.millisecond
+ parent: Date
+weight: 301
+---
+
+The `date.millisecond()` function returns the millisecond of a specified time.
+Results range from `[0-999]`.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.millisecond(t: 2019-07-17T12:05:21.012934584Z)
+
+// Returns 12
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/date/nanosecond.md b/content/v2.0/reference/flux/functions/date/nanosecond.md
new file mode 100644
index 000000000..21f42bdd7
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/nanosecond.md
@@ -0,0 +1,31 @@
+---
+title: date.nanosecond() function
+description: >
+ The `date.nanosecond()` function returns the nanosecond of a specified time.
+ Results range from `[0-999999999]`.
+menu:
+ v2_0_ref:
+ name: date.nanosecond
+ parent: Date
+weight: 301
+---
+
+The `date.nanosecond()` function returns the nanosecond of a specified time.
+Results range from `[0-999999999]`.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.nanosecond(t: 2019-07-17T12:05:21.012934584Z)
+
+// Returns 12934584
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/date/quarter.md b/content/v2.0/reference/flux/functions/date/quarter.md
new file mode 100644
index 000000000..87576ce4c
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/quarter.md
@@ -0,0 +1,31 @@
+---
+title: date.quarter() function
+description: >
+ The `date.quarter()` function returns the quarter of the year for a specified time.
+ Results range from `[1-4]`.
+menu:
+ v2_0_ref:
+ name: date.quarter
+ parent: Date
+weight: 301
+---
+
+The `date.quarter()` function returns the quarter of the year for a specified time.
+Results range from `[1-4]`.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.quarter(t: 2019-07-17T12:05:21.012Z)
+
+// Returns 3
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/date/truncate.md b/content/v2.0/reference/flux/functions/date/truncate.md
new file mode 100644
index 000000000..c9f7db136
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/truncate.md
@@ -0,0 +1,57 @@
+---
+title: date.truncate() function
+description: >
+ The `date.truncate()` function truncates a time to a specified unit.
+menu:
+ v2_0_ref:
+ name: date.truncate
+ parent: Date
+weight: 301
+---
+
+The `date.truncate()` function truncates a time to a specified unit.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.truncate(
+ t: 2019-07-17T12:05:21.012Z
+ unit: 1s
+)
+
+// Returns 2019-07-17T12:05:21.000000000Z
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
+
+### unit
+The unit time to truncate to.
+
+_**Data type:** Duration_
+
+{{% note %}}
+Only use `1` and the unit of time to specify the `unit`.
+For example: `1s`, `1m`, `1h`.
+{{% /note %}}
+
+## Examples
+```js
+import "date"
+
+date.truncate(t: "2019-06-03T13:59:01.000000000Z", unit: 1s)
+// Returns 2019-06-03T13:59:01.000000000Z
+
+date.truncate(t: "2019-06-03T13:59:01.000000000Z", unit: 1m)
+// Returns 2019-06-03T13:59:00.000000000Z
+
+date.truncate(t: "2019-06-03T13:59:01.000000000Z", unit: 1h)
+// Returns 2019-06-03T13:00:00.000000000Z
+
+```
diff --git a/content/v2.0/reference/flux/functions/date/week.md b/content/v2.0/reference/flux/functions/date/week.md
new file mode 100644
index 000000000..8e1bede7b
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/week.md
@@ -0,0 +1,31 @@
+---
+title: date.week() function
+description: >
+ The `date.week()` function returns the ISO week of the year for a specified time.
+ Results range from `[1-53]`.
+menu:
+ v2_0_ref:
+ name: date.week
+ parent: Date
+weight: 301
+---
+
+The `date.week()` function returns the ISO week of the year for a specified time.
+Results range from `[1-53]`.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.week(t: 2019-07-17T12:05:21.012Z)
+
+// Returns 29
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/date/year.md b/content/v2.0/reference/flux/functions/date/year.md
new file mode 100644
index 000000000..d420ed839
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/date/year.md
@@ -0,0 +1,30 @@
+---
+title: date.year() function
+description: >
+ The `date.year()` function returns the year of a specified time.
+menu:
+ v2_0_ref:
+ name: date.year
+ parent: Date
+weight: 301
+draft: true
+---
+
+The `date.year()` function returns the year of a specified time.
+
+_**Function type:** Transformation_
+
+```js
+import "date"
+
+date.year(t: 2019-07-17T12:05:21.012Z)
+
+// Returns 2019
+```
+
+## Parameters
+
+### t
+The time to operate on.
+
+_**Data type:** Time_
diff --git a/content/v2.0/reference/flux/functions/runtime/_index.md b/content/v2.0/reference/flux/functions/runtime/_index.md
new file mode 100644
index 000000000..b940e379a
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/runtime/_index.md
@@ -0,0 +1,22 @@
+---
+title: Flux runtime package
+list_title: Runtime package
+description: >
+ The Flux runtime package includes functions that provide information about the
+ current Flux runtime. Import the `runtime` package.
+menu:
+ v2_0_ref:
+ name: Runtime
+ parent: Flux packages and functions
+weight: 202
+v2.0/tags: [runtime, functions, package]
+---
+
+The Flux runtime package includes functions that provide information about the
+current Flux runtime. Import the `runtime` package:
+
+```js
+import "runtime"
+```
+
+{{< children type="functions" show="pages" >}}
diff --git a/content/v2.0/reference/flux/functions/runtime/version.md b/content/v2.0/reference/flux/functions/runtime/version.md
new file mode 100644
index 000000000..84333887b
--- /dev/null
+++ b/content/v2.0/reference/flux/functions/runtime/version.md
@@ -0,0 +1,20 @@
+---
+title: runtime.version() function
+description: The `runtime.version()` function returns the current Flux version.
+menu:
+ v2_0_ref:
+ name: runtime.version
+ parent: Runtime
+weight: 401
+---
+
+The `runtime.version()` function returns the current Flux version.
+
+_**Function type:** Miscellaneous_
+_**Output data type:** String_
+
+```js
+import "runtime"
+
+runtime.version()
+```
diff --git a/content/v2.0/reference/release-notes/flux.md b/content/v2.0/reference/release-notes/flux.md
index ffb1490e1..f3c011dbc 100644
--- a/content/v2.0/reference/release-notes/flux.md
+++ b/content/v2.0/reference/release-notes/flux.md
@@ -11,13 +11,37 @@ aliases:
---
{{% note %}}
-_The latest release of InfluxDB v2.0 alpha includes **Flux v0.37.2**.
+_The latest release of InfluxDB v2.0 alpha includes **Flux v0.38.0**.
Though newer versions of Flux may be available, they will not be included with
InfluxDB until the next InfluxDB v2.0 release._
{{% /note %}}
---
+## v0.38.0 [2019-08-06]
+
+### Features
+- Update selectors to operate on time columns.
+- Add `relativeStrengthIndex()` transformation.
+- Add double and triple exponential average transformations (`doubleEMA()` and `tripleEMA()`).
+- Add `holtWinters()` transformation.
+- Add `keepFirst` parameter to `difference()`.
+- DatePart equivalent functions.
+- Add runtime package.
+- Add and subtract duration literal arithmetic.
+- Allow `keep()` to run regardless of nonexistent columns.
+ If all columns given are nonexistent, `keep()` returns an empty table.
+- Scanner returns positioning.
+
+### Bug fixes
+- Function resolver now keeps track of local assignments that may be evaluated at runtime.
+- Fixed InfluxDB test errors.
+- Add range to tests to pass in InfluxDB.
+- Allow converting a duration to a duration.
+- Catch integer overflow and underflow for literals.
+
+---
+
## v0.37.2 [2019-07-24]
- _General cleanup of internal code._