diff --git a/promql/functions.go b/promql/functions.go index 016e676d31..da1821fd18 100644 --- a/promql/functions.go +++ b/promql/functions.go @@ -345,11 +345,14 @@ func calcTrendValue(i int, tf, s0, s1, b float64) float64 { return x + y } -// Holt-Winters is similar to a weighted moving average, where historical data has exponentially less influence on the current data. -// Holt-Winter also accounts for trends in data. The smoothing factor (0 < sf < 1) affects how historical data will affect the current -// data. A lower smoothing factor increases the influence of historical data. The trend factor (0 < tf < 1) affects -// how trends in historical data will affect the current data. A higher trend factor increases the influence. -// of trends. Algorithm taken from https://en.wikipedia.org/wiki/Exponential_smoothing titled: "Double exponential smoothing". +// Double exponential smoothing is similar to a weighted moving average, where +// historical data has exponentially less influence on the current data. It also +// accounts for trends in data. The smoothing factor (0 < sf < 1) affects how +// historical data will affect the current data. A lower smoothing factor +// increases the influence of historical data. The trend factor (0 < tf < 1) +// affects how trends in historical data will affect the current data. A higher +// trend factor increases the influence. of trends. Algorithm taken from +// https://en.wikipedia.org/wiki/Exponential_smoothing . func funcDoubleExponentialSmoothing(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) (Vector, annotations.Annotations) { samples := vals[0].(Matrix)[0]