github.com/weaviate/weaviate@v1.24.6/adapters/repos/db/vector/hnsw/distancer/dot_product.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  	"github.com/pkg/errors"
    16  )
    17  
    18  // can be set depending on architecture, e.g. pure go, AVX-enabled assembly, etc.
    19  // Warning: This is not the dot product distance, but the pure product.
    20  //
    21  // This default will always work, regardless of architecture. An init function
    22  // will overwrite it on amd64 if AVX is present.
    23  var dotProductImplementation func(a, b []float32) float32 = func(a, b []float32) float32 {
    24  	var sum float32
    25  	for i := range a {
    26  		sum += a[i] * b[i]
    27  	}
    28  
    29  	return sum
    30  }
    31  
    32  type DotProduct struct {
    33  	a []float32
    34  }
    35  
    36  func (d *DotProduct) Distance(b []float32) (float32, bool, error) {
    37  	if len(d.a) != len(b) {
    38  		return 0, false, errors.Errorf("vector lengths don't match: %d vs %d",
    39  			len(d.a), len(b))
    40  	}
    41  
    42  	dist := -dotProductImplementation(d.a, b)
    43  	return dist, true, nil
    44  }
    45  
    46  type DotProductProvider struct{}
    47  
    48  func NewDotProductProvider() DotProductProvider {
    49  	return DotProductProvider{}
    50  }
    51  
    52  func DotProductGo(a, b []float32) float32 {
    53  	var sum float32
    54  	for i := range a {
    55  		sum += a[i] * b[i]
    56  	}
    57  
    58  	return -sum
    59  }
    60  
    61  func (d DotProductProvider) SingleDist(a, b []float32) (float32, bool, error) {
    62  	if len(a) != len(b) {
    63  		return 0, false, errors.Errorf("vector lengths don't match: %d vs %d",
    64  			len(a), len(b))
    65  	}
    66  
    67  	prod := -dotProductImplementation(a, b)
    68  
    69  	return prod, true, nil
    70  }
    71  
    72  func (d DotProductProvider) Type() string {
    73  	return "dot"
    74  }
    75  
    76  func (d DotProductProvider) New(a []float32) Distancer {
    77  	return &DotProduct{a: a}
    78  }
    79  
    80  func (d DotProductProvider) Step(x, y []float32) float32 {
    81  	var sum float32
    82  	for i := range x {
    83  		sum += x[i] * y[i]
    84  	}
    85  
    86  	return sum
    87  }
    88  
    89  func (d DotProductProvider) Wrap(x float32) float32 {
    90  	return -x
    91  }