Skip to content

rolling-max

Input Stack:
n: Int
expr: TimeSeriesExpr
 ⇨ Output Stack:
TimeSeriesExpr
 

Find the maximum value within a rolling window of datapoints. This operation is useful for tracking peak values, establishing upper bounds for noisy data, and creating envelope functions that follow the highest points in fluctuating signals.

Parameters

  • expr: The time series expression to find rolling maximum for
  • n: Window size (number of datapoints including current value)

Behavior

  • Maximum selection: Returns the highest value in the current window
  • Missing data: NaN values are ignored in the calculation
  • All NaN window: If all values in window are NaN, emits NaN
  • Window-based: Uses fixed number of datapoints, not time duration

Alerting Example

Using rolling max to establish recent peak baseline:

name,sps,:eq,:sum,
:dup,
5,:rolling-max

This creates both the current value and its recent maximum for comparison.

Data Processing Example

Input 3,:rolling-max
0 0
1 1
-1 1
NaN 1
0 0
1 1
1 1
1 1
1 1
0 1

Examples

5-point rolling maximum:

BeforeAfter
:random,
0.4,:gt

:random,
0.4,:gt,
5,:rolling-max

Since: 1.6