fix: metric type inconsistency (#2122)

PR fixes #2113

---------

Co-authored-by: Will Jones <willjones127@gmail.com>

docs/src/ann_indexes.md

@@ -69,7 +69,7 @@ Lance supports `IVF_PQ` index type by default.
 
 The following IVF_PQ paramters can be specified:
 
-- **distance_type**: The distance metric to use. By default it uses euclidean distance "`L2`".
+- **distance_type**: The distance metric to use. By default it uses euclidean distance "`l2`".
   We also support "cosine" and "dot" distance as well.
 - **num_partitions**: The number of partitions in the index. The default is the square root
   of the number of rows.

docs/src/concepts/index_hnsw.md

@@ -59,7 +59,7 @@ Then the greedy search routine operates as follows:
 
 There are three key parameters to set when constructing an HNSW index:
 
-* `metric`: Use an `L2` euclidean distance metric. We also support `dot` and `cosine` distance.
+* `metric`: Use an `l2` euclidean distance metric. We also support `dot` and `cosine` distance.
 * `m`: The number of neighbors to select for each vector in the HNSW graph.
 * `ef_construction`: The number of candidates to evaluate during the construction of the HNSW graph.
 

docs/src/concepts/index_ivfpq.md

@@ -47,7 +47,7 @@ We can combine the above concepts to understand how to build and query an IVF-PQ
 
 There are three key parameters to set when constructing an IVF-PQ index:
 
-* `metric`: Use an `L2` euclidean distance metric. We also support `dot` and `cosine` distance.
+* `metric`: Use an `l2` euclidean distance metric. We also support `dot` and `cosine` distance.
 * `num_partitions`: The number of partitions in the IVF portion of the index.
 * `num_sub_vectors`: The number of sub-vectors that will be created during Product Quantization (PQ).
 
@@ -56,7 +56,7 @@ In Python, the index can be created as follows:
 ```python
 # Create and train the index for a 1536-dimensional vector
 # Make sure you have enough data in the table for an effective training step
-tbl.create_index(metric="L2", num_partitions=256, num_sub_vectors=96)
+tbl.create_index(metric="l2", num_partitions=256, num_sub_vectors=96)
 ```
 !!! note
     `num_partitions`=256 and `num_sub_vectors`=96 does not work for every dataset. Those values needs to be adjusted for your particular dataset.

docs/src/embeddings/understanding_embeddings.md

@@ -54,7 +54,7 @@ As mentioned, after creating embedding, each data point is represented as a vect
 
 Points that are close to each other in vector space are considered similar (or appear in similar contexts), and points that are far away are considered dissimilar. To quantify this closeness, we use distance as a metric which can be measured in the  following way - 
 
-1. **Euclidean Distance (L2)**: It calculates the straight-line distance between two points (vectors) in a multidimensional space.
+1. **Euclidean Distance (l2)**: It calculates the straight-line distance between two points (vectors) in a multidimensional space.
 2. **Cosine Similarity**: It measures the cosine of the angle between two vectors, providing a normalized measure of similarity based on their direction.
 3. **Dot product**: It is calculated as the sum of the products of their corresponding components. To measure relatedness it considers both the magnitude and direction of the vectors.
 

docs/src/integrations/langchain.md

@@ -108,7 +108,7 @@ This method creates a scalar(for non-vector cols) or a vector index on a table.
 |:---|:---|:---|:---|
 |`vector_col`|`Optional[str]`| Provide if you want to create index on a vector column. |`None`|
 |`col_name`|`Optional[str]`| Provide if you want to create index on a non-vector column. |`None`|
-|`metric`|`Optional[str]` |Provide the metric to use for vector index. choice of metrics: 'L2', 'dot', 'cosine'. |`L2`|
+|`metric`|`Optional[str]` |Provide the metric to use for vector index. choice of metrics: 'l2', 'dot', 'cosine'. |`l2`|
 |`num_partitions`|`Optional[int]`|Number of partitions to use for the index.|`256`|
 |`num_sub_vectors`|`Optional[int]` |Number of sub-vectors to use for the index.|`96`|
 |`index_cache_size`|`Optional[int]` |Size of the index cache.|`None`|

docs/src/integrations/llamaIndex.md

@@ -125,7 +125,7 @@ The exhaustive list of parameters for `LanceDBVectorStore` vector store are :
         ```               
 - **_table_exists(self, tbl_name: `Optional[str]` = `None`) -> `bool`** : Returns `True` if `tbl_name` exists in database.
 - __create_index(  
-  self, scalar: `Optional[bool]` = False, col_name: `Optional[str]` = None, num_partitions: `Optional[int]` = 256, num_sub_vectors: `Optional[int]` = 96, index_cache_size: `Optional[int]` = None, metric: `Optional[str]` = "L2",  
+  self, scalar: `Optional[bool]` = False, col_name: `Optional[str]` = None, num_partitions: `Optional[int]` = 256, num_sub_vectors: `Optional[int]` = 96, index_cache_size: `Optional[int]` = None, metric: `Optional[str]` = "l2",  
 ) -> `None`__ : Creates a scalar(for non-vector cols) or a vector index on a table.
         Make sure your vector column has enough data before creating an index on it.
 

docs/src/javascript/enums/MetricType.md

@@ -10,7 +10,7 @@ Distance metrics type.
 
 - [Cosine](MetricType.md#cosine)
 - [Dot](MetricType.md#dot)
-- [L2](MetricType.md#l2)
+- [l2](MetricType.md#l2)
 
 ## Enumeration Members
 

docs/src/javascript/interfaces/IvfPQIndexConfig.md

@@ -85,7 +85,7 @@ ___
 
 • `Optional` **metric\_type**: [`MetricType`](../enums/MetricType.md)
 
-Metric type, L2 or Cosine
+Metric type, l2 or Cosine
 
 #### Defined in
 

docs/src/js/interfaces/HnswPqOptions.md

@@ -24,18 +24,18 @@ The following distance types are available:
 
 "l2" - Euclidean distance. This is a very common distance metric that
 accounts for both magnitude and direction when determining the distance
-between vectors. L2 distance has a range of [0, ∞).
+between vectors. l2 distance has a range of [0, ∞).
 
 "cosine" - Cosine distance.  Cosine distance is a distance metric
 calculated from the cosine similarity between two vectors. Cosine
 similarity is a measure of similarity between two non-zero vectors of an
 inner product space. It is defined to equal the cosine of the angle
-between them.  Unlike L2, the cosine distance is not affected by the
+between them.  Unlike l2, the cosine distance is not affected by the
 magnitude of the vectors.  Cosine distance has a range of [0, 2].
 
 "dot" - Dot product. Dot distance is the dot product of two vectors. Dot
 distance has a range of (-∞, ∞). If the vectors are normalized (i.e. their
-L2 norm is 1), then dot distance is equivalent to the cosine distance.
+l2 norm is 1), then dot distance is equivalent to the cosine distance.
 
 ***
 

docs/src/js/interfaces/HnswSqOptions.md

@@ -24,18 +24,18 @@ The following distance types are available:
 
 "l2" - Euclidean distance. This is a very common distance metric that
 accounts for both magnitude and direction when determining the distance
-between vectors. L2 distance has a range of [0, ∞).
+between vectors. l2 distance has a range of [0, ∞).
 
 "cosine" - Cosine distance.  Cosine distance is a distance metric
 calculated from the cosine similarity between two vectors. Cosine
 similarity is a measure of similarity between two non-zero vectors of an
 inner product space. It is defined to equal the cosine of the angle
-between them.  Unlike L2, the cosine distance is not affected by the
+between them.  Unlike l2, the cosine distance is not affected by the
 magnitude of the vectors.  Cosine distance has a range of [0, 2].
 
 "dot" - Dot product. Dot distance is the dot product of two vectors. Dot
 distance has a range of (-∞, ∞). If the vectors are normalized (i.e. their
-L2 norm is 1), then dot distance is equivalent to the cosine distance.
+l2 norm is 1), then dot distance is equivalent to the cosine distance.
 
 ***
 

docs/src/js/interfaces/IvfPqOptions.md

@@ -31,13 +31,13 @@ The following distance types are available:
 
 "l2" - Euclidean distance. This is a very common distance metric that
 accounts for both magnitude and direction when determining the distance
-between vectors. L2 distance has a range of [0, ∞).
+between vectors. l2 distance has a range of [0, ∞).
 
 "cosine" - Cosine distance.  Cosine distance is a distance metric
 calculated from the cosine similarity between two vectors. Cosine
 similarity is a measure of similarity between two non-zero vectors of an
 inner product space. It is defined to equal the cosine of the angle
-between them.  Unlike L2, the cosine distance is not affected by the
+between them.  Unlike l2, the cosine distance is not affected by the
 magnitude of the vectors.  Cosine distance has a range of [0, 2].
 
 Note: the cosine distance is undefined when one (or both) of the vectors
@@ -46,7 +46,7 @@ never be returned from a vector search.
 
 "dot" - Dot product. Dot distance is the dot product of two vectors. Dot
 distance has a range of (-∞, ∞). If the vectors are normalized (i.e. their
-L2 norm is 1), then dot distance is equivalent to the cosine distance.
+l2 norm is 1), then dot distance is equivalent to the cosine distance.
 
 ***
 

docs/src/search.md

@@ -15,7 +15,7 @@ Currently, LanceDB supports the following metrics:
 
 | Metric    | Description                                                                 |
 | --------- | --------------------------------------------------------------------------- |
-| `l2`      | [Euclidean / L2 distance](https://en.wikipedia.org/wiki/Euclidean_distance) |
+| `l2`      | [Euclidean / l2 distance](https://en.wikipedia.org/wiki/Euclidean_distance) |
 | `cosine`  | [Cosine Similarity](https://en.wikipedia.org/wiki/Cosine_similarity)        |
 | `dot`     | [Dot Production](https://en.wikipedia.org/wiki/Dot_product)                 |
 | `hamming` | [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance)          |