relativeStrengthIndex() function

The relativeStrengthIndex() function measures the relative speed and change of values in an input table.

*Function type: Transformation*

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*

Output tables

For each input table with x rows, relativeStrengthIndex() outputs a table with x - n rows.

Examples

Calculate a five point relative strength index

from(bucket: "example-bucket"):
  |> range(start: -12h)
  |> relativeStrengthIndex(n: 5)

Table transformation with a ten point RSI

Input table:

Query:

// ...
  |> relativeStrengthIndex(
    n: 10,
    columns: ["A", "B"]
  )

Output table:

Related articles

• movingAverage() function
• timedMovingAverage() function
• exponentialMovingAverage() function
• InfluxQL RELATIVE_STRENGTH_INDEX()