Configure indexes

To configure indexes for similarity searches, you need to configure the following fields.

`NearestNeighborSearch`

Fields

Fields
`contentsDeltaUri`	`string` Allows inserting, updating or deleting the contents of the Matching Engine `Index`. The string must be a valid Cloud Storage directory path, such as `gs://BUCKET_NAME/PATH_TO_INDEX_DIR/`. If you set this field when calling `IndexService.UpdateIndex`, then no other `Index` field can be also updated as part of the same call. Learn how to structure individual data files.
`isCompleteOverwrite`	`boolean` If this field is set together with `contentsDeltaUri` when calling `IndexService.UpdateIndex`, then existing content of the `Index` will be replaced by the data from the `contentsDeltaUri`.
`config`	`NearestNeighborSearchConfig` The configuration of the Matching Engine `Index`.

contentsDeltaUri

string

Allows inserting, updating or deleting the contents of the Matching Engine Index. The string must be a valid Cloud Storage directory path, such as gs://BUCKET_NAME/PATH_TO_INDEX_DIR/.

If you set this field when calling IndexService.UpdateIndex, then no other Index field can be also updated as part of the same call. Learn how to structure individual data files.

isCompleteOverwrite

boolean

If this field is set together with contentsDeltaUri when calling IndexService.UpdateIndex, then existing content of the Index will be replaced by the data from the contentsDeltaUri.

config

NearestNeighborSearchConfig

The configuration of the Matching Engine Index.

`NearestNeighborSearchConfig`

Fields
`dimensions`	`int32` Required. The number of dimensions of the input vectors.
`approximateNeighborsCount`	`int32` Required if tree-AH algorithm is used. The default number of neighbors to find through approximate search before exact reordering is performed. Exact reordering is a procedure where results returned by an approximate search algorithm are reordered via a more expensive distance computation.
`distanceMeasureType`	`DistanceMeasureType` The distance measure used in nearest neighbor search.
`featureNormType`	`FeatureNormType` Type of normalization to be carried out on each vector.
`algorithmConfig`	`oneOf:` `TreeAhConfig` `BruteForceConfig` The configuration for the algorithms that Matching Engine uses for efficient search. `TreeAhConfig`: Configuration options for using the tree-AH algorithm (Shallow tree + Asymmetric Hashing). Refer to this paper for more details: https://arxiv.org/abs/1908.10396 `BruteForceConfig`: This option implements the standard linear search in the database for each query. There are no fields to configure for a brute force search. To select this algorithm, pass an empty object for `BruteForceConfig`.

`DistanceMeasureType`

Enums
`SQUARED_L2_DISTANCE`	Euclidean (L₂) Distance
`L1_DISTANCE`	Manhattan (L₁) Distance
`COSINE_DISTANCE`	Cosine Distance. Defined as `1 - cosine` similarity.
`DOT_PRODUCT_DISTANCE`	Default value. Defined as a negative of the dot product.

`FeatureNormType`

Enums
`UNIT_L2_NORM`	Unit L2 normalization type.
`NONE`	Default value. No normalization type is specified.

`TreeAhConfig`

These are the fields to select for the tree-AH algorithm (Shallow tree + Asymmetric Hashing).

Fields
`leafNodeEmbeddingCount`	`int32`
	Number of embeddings on each leaf node. The default value is 1000 if not set.
`leafNodesToSearchPercent`	`int32`
	The default percentage of leaf nodes that any query may be searched. Must be in range 1-100, inclusive. The default value is 10 (means 10%) if not set.

`BruteForceConfig`

This option implements the standard linear search in the database for each query. There are no fields to configure for a brute force search. To select this algorithm, pass an empty object for BruteForceConfig to algorithmConfig.