Added support for creating a SparseVector from a map

Author: ankane

lib/pgvector/sparse_vector.ex

@@ -34,6 +34,19 @@ defmodule Pgvector.SparseVector do
     end
   end
 
+  @doc """
+  Creates a new sparse vector from a map
+  """
+  def new(map, dimensions) when is_map(map) do
+    {indices, values} =
+      map
+      |> Enum.sort_by(fn {k, _} -> k end)
+      |> Enum.filter(fn {_, v} -> v != 0 end)
+      |> Enum.unzip()
+
+    new(dimensions, indices, values)
+  end
+
   defp new(dim, indices, values) do
     nnz = indices |> length()
     indices = for v <- indices, into: "", do: <<v::signed-32>>

test/sparse_vector_test.exs

@@ -16,6 +16,11 @@ defmodule SparseVectorTest do
     assert tensor == tensor |> Pgvector.SparseVector.new() |> Pgvector.to_tensor()
   end
 
+  test "map" do
+    map = %{0 => 1.0, 2 => 2.0, 4 => 3.0}
+    assert [1.0, 0.0, 2.0, 0.0, 3.0, 0.0] == map |> Pgvector.SparseVector.new(6) |> Pgvector.to_list()
+  end
+
   test "inspect" do
     vector = Pgvector.SparseVector.new([1, 2, 3])
     assert "Pgvector.SparseVector.new([1.0, 2.0, 3.0])" == inspect(vector)