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- Added mv_median_absolute_deviation function - Added possibility of having a fixed param in Multivalue "ascending" functions - Add surrogate to MedianAbsoluteDeviation ### Calculations used to avoid overflows First, a quick recap of how the MAD is calculated: 1. Sort values, and get the median 2. Calculate the difference between each value with the median (`abs(median - value)`) 3. Sort the differences, and get their median Calculating a MAD may overflow when calculating the differences (Step 2), given the type is a signed number, as the difference is a positive value, with potentially the same value as `POSITIVE_MAX - NEGATIVE_MIN`. To solve this, some types are up-casted as follow: - Int: Stored as longs, simple approach - Long: Stored as longs, but switched to unsigned long representation when calculating the differences - Unsigned long: No effect; the resulting range is the same - Doubles: Nothing. If the values overflow to +/-infinity, they're left that way, as we'll just use those outliers to sort Closes https://github.com/elastic/elasticsearch/issues/111590
22 lines
963 B
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22 lines
963 B
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// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
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*Examples*
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[source.merge.styled,esql]
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----
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include::{esql-specs}/median_absolute_deviation.csv-spec[tag=median-absolute-deviation]
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----
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[%header.monospaced.styled,format=dsv,separator=|]
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include::{esql-specs}/median_absolute_deviation.csv-spec[tag=median-absolute-deviation-result]
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The expression can use inline functions. For example, to calculate the the median absolute deviation of the maximum values of a multivalued column, first use `MV_MAX` to get the maximum value per row, and use the result with the `MEDIAN_ABSOLUTE_DEVIATION` function
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[source.merge.styled,esql]
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----
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include::{esql-specs}/median_absolute_deviation.csv-spec[tag=docsStatsMADNestedExpression]
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----
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[%header.monospaced.styled,format=dsv,separator=|]
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include::{esql-specs}/median_absolute_deviation.csv-spec[tag=docsStatsMADNestedExpression-result]
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