Added l1_distance function for Ecto

Author: ankane

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
           dev-files: true
       - run: |
           cd /tmp
-          git clone --branch v0.6.0 https://github.com/pgvector/pgvector.git
+          git clone --branch v0.7.0 https://github.com/pgvector/pgvector.git
           cd pgvector
           make
           sudo make install

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.2.2 (unreleased)
+
+- Added `l1_distance` function for Ecto
+
 ## 0.2.1 (2023-09-25)
 
 - Added support for `Pgvector` to `Pgvector.new/1`

lib/pgvector/ecto/query.ex

@@ -30,5 +30,14 @@ if Code.ensure_loaded?(Ecto) do
         fragment("(? <=> ?::vector)", unquote(column), unquote(value))
       end
     end
+
+    @doc """
+    Returns the L1 distance
+    """
+    defmacro l1_distance(column, value) do
+      quote do
+        fragment("(? <+> ?::vector)", unquote(column), unquote(value))
+      end
+    end
   end
 end

test/ecto_test.exs

@@ -47,6 +47,12 @@ defmodule EctoTest do
     assert Enum.map(items, fn v -> v.id end) == [3, 2, 1]
   end
 
+  test "l1 distance" do
+    items = Repo.all(from i in Item, order_by: l1_distance(i.embedding, [1, 1, 1]), limit: 5)
+    assert Enum.map(items, fn v -> v.id end) == [1, 3, 2]
+    assert Enum.map(items, fn v -> v.embedding |> Pgvector.to_list() end) == [[1.0, 1.0, 1.0], [1.0, 1.0, 2.0], [2.0, 2.0, 3.0]]
+  end
+
   test "cast" do
     embedding = [1, 1, 1]
     items = Repo.all(from i in Item, where: i.embedding == ^embedding)