tmstdTopN

Syntax

tmstdTopN(T, X, S, window, top, [ascending=true], [tiesMethod=’latest’])

Please see Time-Based Moving TopN Functions (tmTopN functions) for the parameters and windowing logic.

Details

After stably sorting S in the specified ascending order, the function calculates the standard deviation of the first top elements of X in a sliding window.

Return value: a vector of DOUBLE type

Examples

$ T=2023.01.03+1..7
$ X = [2, 1, 4, 3, 4, 3, 1]
$ S = [5, 8, 1, , 1, 1, 3]
// The NULL values in S are ignored in data sorting, and the corresponding elements in X do not participate in calculation
$ tmstdTopN(T,X,S,6,4)
[,0.7071,1.5275,1.5275,1.5,0.9574,1.4142]

$ T=2023.01.03 2023.01.07 2023.01.08 2023.01.10 2023.01.11 2023.01.12
$ X=8 3 1 2 5 2
$ S=1 5 2 3 1 1
$ t=table(T as time, X as val, S as id)
$ select tmstdTopN(time,val,id,4,3) as topN from t

topN
1.4142
1
2.0816
1.732

Related function: tmstd