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reducer.sd.welford.forbid-nulls

reducer

The reducer.sd.welford.forbid-nulls function outputs for each tick the standard deviation of the values of Geo Time Series™ which are in the same equivalence class.

This is similar to reducer.sd.forbid-nulls except this version implements Welford's method which is 10% slower but is much less subject to numerical instability.

It operates on LONG and DOUBLE.

The location and elevation returned are the first encountered.

This reducer takes an additional boolean parameter to choose if Bessel correction should be applied.

It will return null for any tick where one or more GTS have null values.

reducer.sd.welford.forbid-nulls is available since version 2.9.0.

See also

Signatures

Examples

[ [ NEWGTS "GTS1" RENAME 10 NaN NaN NaN 1 ADDVALUE 20 NaN NaN NaN 5 ADDVALUE NEWGTS "GTS2" RENAME 10 NaN NaN NaN 4 ADDVALUE 20 NaN NaN NaN 3 ADDVALUE NEWGTS "GTS3" RENAME 10 NaN NaN NaN 3 ADDVALUE 20 NaN NaN NaN 8 ADDVALUE NEWGTS "GTS4" RENAME 10 NaN NaN NaN 3 ADDVALUE 20 NaN NaN NaN 2 ADDVALUE ] [] true reducer.sd.welford.forbid-nulls ] REDUCE