series-cosine-similarity-function.md

title	description	ms.reviewer	ms.topic	ms.date
series_cosine_similarity()	This article describes series_cosine_similarity().	adieldar	reference	08/11/2024

series_cosine_similarity()

[!INCLUDE applies] [!INCLUDE fabric] [!INCLUDE azure-data-explorer] [!INCLUDE monitor] [!INCLUDE sentinel]

Calculate the cosine similarity of two numerical vectors.

The function series_cosine_similarity() takes two numeric series as input, and calculates their cosine similarity.

Syntax

series_cosine_similarity(series1, series2, [*magnitude1, [*magnitude2]])

[!INCLUDE syntax-conventions-note]

Parameters

Name	Type	Required	Description
series1, series2	dynamic	✔️	Input arrays with numeric data.
magnitude1, magnitude2	real		Optional magnitude of the first and the second vectors respectively. The magnitude is the square root of the dot product of the vector with itself. If the magnitude isn't provided, it will be calculated.

Returns

Returns a value of type real whose value is the cosine similarity of series1 with series2. In case both series length isn't equal, the longer series will be truncated to the length of the shorter one. Any non-numeric element of the input series will be ignored.

Note

If one or both input arrays are empty, the result will be null.

[!INCLUDE optimization-note]

Example

[!div class="nextstepaction"] Run the query

datatable(s1:dynamic, s2:dynamic)
[
    dynamic([0.1,0.2,0.1,0.2]), dynamic([0.11,0.2,0.11,0.21]),
    dynamic([0.1,0.2,0.1,0.2]), dynamic([1,2,3,4]),
]
| extend cosine_similarity=series_cosine_similarity(s1, s2)

s1	s2	cosine_similarity
[0.1,0.2,0.1,0.2]	[0.11,0.2,0.11,0.21]	0.99935343825504
[0.1,0.2,0.1,0.2]	[1,2,3,4]	0.923760430703401

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