cts:stddev-p( $range-index as cts:reference, [$options as xs:string*], [$query as cts:query?], [$forest-ids as xs:unsignedLong*] ) as xs:double?
Returns a frequency-weighted standard deviation of the population given
a value lexicon. This function works like math:stddev-p
except each item in the lexicon is counted cts:frequency
times.
This function performs the calculation in parallel in all data nodes
then aggregates the values.
The function returns the empty sequence if the lexicon contains no value.
xquery version "1.0-ml"; (: This query assumes an int range index is configured in the database. It generates some sample data and then performs the aggregation in a separate transaction. :) for $x in 1 to 10 return xdmp:document-insert(fn:concat($x, ".xml"), <my-element>{ for $y in 1 to $x return <int>{$x}</int> }</my-element>); cts:stddev-p( cts:element-reference(xs:QName("int"),"type=int"), ("item-frequency","concurrent")), cts:stddev-p( cts:element-reference(xs:QName("int"),"type=int"), ("fragment-frequency","concurrent")) => 2.44948974278318 2.87228132326901
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