44 lines
2.1 KiB
Plaintext
44 lines
2.1 KiB
Plaintext
[role="xpack"]
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[[ml-functions]]
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= Function reference
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The {ml-features} include analysis functions that provide a wide variety of
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flexible ways to analyze data for anomalies.
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When you create {anomaly-jobs}, you specify one or more detectors, which define
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the type of analysis that needs to be done. If you are creating your job by
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using {ml} APIs, you specify the functions in detector configuration objects.
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If you are creating your job in {kib}, you specify the functions differently
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depending on whether you are creating single metric, multi-metric, or advanced
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jobs.
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Most functions detect anomalies in both low and high values. In statistical
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terminology, they apply a two-sided test. Some functions offer low and high
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variations (for example, `count`, `low_count`, and `high_count`). These variations
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apply one-sided tests, detecting anomalies only when the values are low or
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high, depending one which alternative is used.
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You can specify a `summary_count_field_name` with any function except `metric`.
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When you use `summary_count_field_name`, the {ml} features expect the input
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data to be pre-aggregated. The value of the `summary_count_field_name` field
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must contain the count of raw events that were summarized. In {kib}, use the
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**summary_count_field_name** in advanced {anomaly-jobs}. Analyzing aggregated
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input data provides a significant boost in performance. For more information, see
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<<ml-configuring-aggregation>>.
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If your data is sparse, there may be gaps in the data which means you might have
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empty buckets. You might want to treat these as anomalies or you might want these
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gaps to be ignored. Your decision depends on your use case and what is important
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to you. It also depends on which functions you use. The `sum` and `count`
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functions are strongly affected by empty buckets. For this reason, there are
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`non_null_sum` and `non_zero_count` functions, which are tolerant to sparse data.
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These functions effectively ignore empty buckets.
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* <<ml-count-functions>>
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* <<ml-geo-functions>>
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* <<ml-info-functions>>
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* <<ml-metric-functions>>
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* <<ml-rare-functions>>
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* <<ml-sum-functions>>
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* <<ml-time-functions>>
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