github.com/weaviate/weaviate@v1.24.6/adapters/repos/db/vector/hnsw/distancer/cosine_dist_test.go (about)

     1  //                           _       _
     2  // __      _____  __ ___   ___  __ _| |_ ___
     3  // \ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \
     4  //  \ V  V /  __/ (_| |\ V /| | (_| | ||  __/
     5  //   \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___|
     6  //
     7  //  Copyright © 2016 - 2024 Weaviate B.V. All rights reserved.
     8  //
     9  //  CONTACT: hello@weaviate.io
    10  //
    11  
    12  package distancer
    13  
    14  import (
    15  	"testing"
    16  
    17  	"github.com/stretchr/testify/assert"
    18  	"github.com/stretchr/testify/require"
    19  )
    20  
    21  func TestCosineDistancer(t *testing.T) {
    22  	t.Run("identical vectors", func(t *testing.T) {
    23  		vec1 := Normalize([]float32{0.1, 0.3, 0.7})
    24  		vec2 := Normalize([]float32{0.1, 0.3, 0.7})
    25  		expectedDistance := float32(0.0)
    26  
    27  		dist, ok, err := NewCosineDistanceProvider().New(vec1).Distance(vec2)
    28  		require.Nil(t, err)
    29  		require.True(t, ok)
    30  		control, ok, err := NewCosineDistanceProvider().SingleDist(vec1, vec2)
    31  		require.True(t, ok)
    32  		require.Nil(t, err)
    33  		assert.Equal(t, control, dist)
    34  		assert.Equal(t, expectedDistance, dist)
    35  	})
    36  
    37  	t.Run("different vectors, but identical angle", func(t *testing.T) {
    38  		vec1 := Normalize([]float32{0.1, 0.3, 0.7})
    39  		vec2 := Normalize([]float32{0.2, 0.6, 1.4})
    40  		expectedDistance := float32(0.0)
    41  
    42  		dist, ok, err := NewCosineDistanceProvider().New(vec1).Distance(vec2)
    43  		require.Nil(t, err)
    44  		require.True(t, ok)
    45  		control, ok, err := NewCosineDistanceProvider().SingleDist(vec1, vec2)
    46  		require.True(t, ok)
    47  		require.Nil(t, err)
    48  		assert.Equal(t, control, dist)
    49  		assert.Equal(t, expectedDistance, dist)
    50  	})
    51  
    52  	t.Run("different vectors", func(t *testing.T) {
    53  		vec1 := Normalize([]float32{0.1, 0.3, 0.7})
    54  		vec2 := Normalize([]float32{0.2, 0.2, 0.2})
    55  		expectedDistance := float32(0.173)
    56  
    57  		dist, ok, err := NewCosineDistanceProvider().New(vec1).Distance(vec2)
    58  		require.Nil(t, err)
    59  		require.True(t, ok)
    60  		control, ok, err := NewCosineDistanceProvider().SingleDist(vec1, vec2)
    61  		require.True(t, ok)
    62  		require.Nil(t, err)
    63  		assert.Equal(t, control, dist)
    64  		assert.InDelta(t, expectedDistance, dist, 0.01)
    65  	})
    66  
    67  	t.Run("opposite vectors", func(t *testing.T) {
    68  		// This is unique to cosine/angular distance.
    69  		vec1 := Normalize([]float32{0.1, 0.3, 0.7})
    70  		vec2 := Normalize([]float32{-0.1, -0.3, -0.7})
    71  		expectedDistance := float32(2)
    72  
    73  		dist, ok, err := NewCosineDistanceProvider().New(vec1).Distance(vec2)
    74  		require.Nil(t, err)
    75  		require.True(t, ok)
    76  		control, ok, err := NewCosineDistanceProvider().SingleDist(vec1, vec2)
    77  		require.True(t, ok)
    78  		require.Nil(t, err)
    79  		assert.Equal(t, control, dist)
    80  		assert.InDelta(t, expectedDistance, dist, 0.01)
    81  	})
    82  }
    83  
    84  func TestCosineDistancerStepbyStep(t *testing.T) {
    85  	t.Run("step by step equals SingleDist", func(t *testing.T) {
    86  		vec1 := Normalize([]float32{3, 4, 5})
    87  		vec2 := Normalize([]float32{-3, -4, -5})
    88  
    89  		expectedDistance, ok, err := NewCosineDistanceProvider().New(vec1).Distance(vec2)
    90  		require.Nil(t, err)
    91  		require.True(t, ok)
    92  
    93  		distanceProvider := NewCosineDistanceProvider()
    94  		sum := float32(0.0)
    95  		for i := range vec1 {
    96  			sum += distanceProvider.Step([]float32{vec1[i]}, []float32{vec2[i]})
    97  		}
    98  		control := distanceProvider.Wrap(sum)
    99  
   100  		assert.Equal(t, control, expectedDistance)
   101  	})
   102  }