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docs/en/engines/table-engines/mergetree-family/annindexes.md
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@ -149,8 +149,8 @@ was specified for ANN indexes, the default value is 100 million.
Annoy indexes are currently experimental, to use them you first need to `SET allow_experimental_annoy_index = 1`. They are also currently
disabled on ARM due to memory safety problems with the algorithm.
This type of ANN index implements [the Annoy algorithm](https://github.com/spotify/annoy) which is based on a recursive division of the
space in random linear surfaces (lines in 2D, planes in 3D etc.).
This type of ANN index is based on the [Annoy library](https://github.com/spotify/annoy) which recursively divides the space into random
linear surfaces (lines in 2D, planes in 3D etc.).
<div class='vimeo-container'>
<iframe src="//www.youtube.com/embed/QkCCyLW0ehU"
@ -219,12 +219,25 @@ LIMIT N
SETTINGS annoy_index_search_k_nodes=100;
```
## USearch {#usearch}
USearch indexes are currently experimental, to use them you first need to `SET allow_experimental_usearch_index = 1`.
This type of ANN index implements [the HNSW algorithm](https://github.com/unum-cloud/usearch).
This type of ANN index is based on the [the USearch library](https://github.com/unum-cloud/usearch) which implements the [HNSW
algorithm](https://arxiv.org/abs/1603.09320), i.e. builds a hierarchical graph where each point represents a vector and the edges represent
similarity.
<div class='vimeo-container'>
<iframe src="//www.youtube.com/embed/QvKMwLjdK-s"
width="640"
height="360"
frameborder="0"
allow="autoplay;
fullscreen;
picture-in-picture"
allowfullscreen>
</iframe>
</div>
Syntax to create an USearch index over an [Array](../../../sql-reference/data-types/array.md) column:
@ -259,4 +272,4 @@ USearch currently supports two distance functions:
([Wikipedia](https://en.wikipedia.org/wiki/Cosine_similarity)).
For normalized data, `L2Distance` is usually a better choice, otherwise `cosineDistance` is recommended to compensate for scale. If no
distance function was specified during index creation, `L2Distance` is used as default.
distance function was specified during index creation, `L2Distance` is used as default.