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The purpose of this check is to test for trends in the input timeseries and send log messages whenever a trend is detected. One of the strengths of the Mann-Kendall check is that it also be used when there are lots of missing values. Unfortunately there is a limit on the number of non-missings that can be processed reasonably, since the calculation of the slopes requires memory for n * (n + 1) / 2 values. It is therefore recommended to aggregate the values first when there are many values in the timeseries to be checked.
During the check, the threshold criteria for the check are first sorted. The most severe log message is processed first and when the log message is generated the less serious log message will not be generated.
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