kshard · fogfish · Feb 28, 2024 · Feb 28, 2024 · Feb 28, 2024
diff --git a/README.md b/README.md
@@ -73,11 +73,28 @@ Instruction pipeline is 3.3x faster and SIMD is 3.8x faster (due to [bounds chec
 ```
 go test -run=^$ -bench=. -cpu=1
 
-BenchmarkPureEuclideanF32    4072329        270.5 ns/op
-BenchmarkNoAsmEuclideanF32  14938154         81.59 ns/op
-BenchmarkSIMDEuclideanF32   16888236         71.15 ns/op
-BenchmarkPureCosineF32       3987426        299.8 ns/op
-BenchmarkNoAsmCosineF32     11738499        102.2 ns/op
+BenchmarkPureEuclideanF32          4072329        270.50 ns/op
+BenchmarkNoAsmEuclideanF32        14938154         81.59 ns/op
+BenchmarkSIMDEuclideanF32         16888236         71.15 ns/op
+BenchmarkContraMapEuclidean       16595740         71.25 ns/op
+BenchmarkPureCosineF32             3987426        299.80 ns/op
+BenchmarkNoAsmCosineF32           11738499        102.20 ns/op
+```
+
+## High-level abstraction
+
+**ContraMap** turn morphisms around `f: B ⟼ A`.
+
+```go
+type Node struct {
+  ID     int
+  Vector vector.F32
+}
+
+vector.ContraMap[vector.F32, Node]{
+	Surface:   vector.Euclidean(),
+	ContraMap: func(n Node) []float32 { return n.Vector },
+}
 ```
 
 
@@ -103,7 +120,8 @@ go test
 
 Checklist:
 1. No new bounds check introduced: `go build -gcflags="-d=ssa/check_bce"`
-2. No performance degradations: `go test -run=^$ -bench=. -cpu=1`
+2. Check inlining: `go build -gcflags "-m"`
+3. No performance degradations: `go test -run=^$ -bench=. -cpu=1`
 
 
 ### commit message

diff --git a/distance.go b/distance.go
@@ -0,0 +1,87 @@
+//
+// Copyright (C) 2024 Dmitry Kolesnikov
+//
+// This file may be modified and distributed under the terms
+// of the MIT license.  See the LICENSE file for details.
+// https://github.com/kshard/vector
+//
+
+package vector
+
+import (
+	"github.com/kshard/vector/internal/noasm"
+	"github.com/kshard/vector/internal/pure"
+	"github.com/kshard/vector/internal/simd"
+)
+
+//
+// Euclidean
+//
+
+const (
+	EUCLIDEAN_WITH_PURE = iota
+	EUCLIDEAN_WITH_NOASM
+	EUCLIDEAN_WITH_SIMD
+)
+
+// Squared Euclidean distance between two vectors
+func Euclidean() interface{ Distance(F32, F32) float32 } {
+	switch euclideanConfig() {
+	case EUCLIDEAN_WITH_PURE:
+		return pure.Euclidean(0)
+	case EUCLIDEAN_WITH_NOASM:
+		return noasm.Euclidean(0)
+	case EUCLIDEAN_WITH_SIMD:
+		return simd.Euclidean{}
+	}
+
+	return nil
+}
+
+func euclideanConfig() int {
+	if simd.ENABLED_EUCLIDEAN {
+		return EUCLIDEAN_WITH_SIMD
+	}
+
+	if noasm.ENABLED_EUCLIDEAN {
+		return EUCLIDEAN_WITH_NOASM
+	}
+
+	return EUCLIDEAN_WITH_PURE
+}
+
+//
+// Cosine
+//
+
+const (
+	COSINE_WITH_PURE = iota
+	COSINE_WITH_NOASM
+	COSINE_WITH_SIMD
+)
+
+// Cosine Distance
+func Cosine() interface{ Distance(F32, F32) float32 } {
+	switch cosineConfig() {
+	case COSINE_WITH_PURE:
+		return pure.Cosine(0)
+	case COSINE_WITH_NOASM:
+		return noasm.Cosine(0)
+		// case COSINE_WITH_SIMD:
+		// 	return simd.Euclidean{}
+	}
+
+	return nil
+}
+
+func cosineConfig() int {
+	if simd.ENABLED_COSINE {
+		return COSINE_WITH_SIMD
+	}
+
+	if noasm.ENABLED_COSINE {
+		return COSINE_WITH_NOASM
+	}
+
+	return COSINE_WITH_PURE
+}
diff --git a/go.mod b/go.mod
@@ -4,5 +4,6 @@ go 1.22.0
 
 require (
 	github.com/chewxy/math32 v1.10.1
+	github.com/fogfish/golem/pure v0.10.1
 	golang.org/x/sys v0.17.0
 )
diff --git a/go.sum b/go.sum
@@ -1,4 +1,6 @@
 github.com/chewxy/math32 v1.10.1 h1:LFpeY0SLJXeaiej/eIp2L40VYfscTvKh/FSEZ68uMkU=
 github.com/chewxy/math32 v1.10.1/go.mod h1:dOB2rcuFrCn6UHrze36WSLVPKtzPMRAQvBvUwkSsLqs=
+github.com/fogfish/golem/pure v0.10.1 h1:0+cnvdaV9zF+0NN8SZMgR5bgFM6yNfBHU4rynYSDfmE=
+github.com/fogfish/golem/pure v0.10.1/go.mod h1:kLPfgu5uKP0CrwVap7jejisRwV7vo1q8Eyqnc/Z0qyw=
 golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
 golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
diff --git a/info.go b/info.go
@@ -0,0 +1,24 @@
+//
+// Copyright (C) 2024 Dmitry Kolesnikov
+//
+// This file may be modified and distributed under the terms
+// of the MIT license.  See the LICENSE file for details.
+// https://github.com/kshard/vector
+//
+
+package vector
+
+const (
+	CONFIG_EUCLIDEAN = "euclidean"
+	CONFIG_COSINE    = "cosine"
+)
+
+// Info about config
+func Info() map[string]int {
+	info := map[string]int{}
+
+	info[CONFIG_EUCLIDEAN] = euclideanConfig()
+	info[CONFIG_COSINE] = cosineConfig()
+
+	return info
+}
diff --git a/types.go b/types.go
@@ -9,89 +9,34 @@
 package vector
 
 import (
-	"github.com/kshard/vector/internal/noasm"
-	"github.com/kshard/vector/internal/pure"
-	"github.com/kshard/vector/internal/simd"
+	"github.com/fogfish/golem/pure"
 )
 
 // Vector of float32
 type F32 = []float32
 
-const (
-	EUCLIDEAN_WITH_PURE = iota
-	EUCLIDEAN_WITH_NOASM
-	EUCLIDEAN_WITH_SIMD
-)
-
-// Squared Euclidean distance between two vectors
-func Euclidean() interface{ Distance(F32, F32) float32 } {
-	switch euclideanConfig() {
-	case EUCLIDEAN_WITH_PURE:
-		return pure.Euclidean(0)
-	case EUCLIDEAN_WITH_NOASM:
-		return noasm.Euclidean(0)
-	case EUCLIDEAN_WITH_SIMD:
-		return simd.Euclidean{}
-	}
-
-	return nil
-}
-
-func euclideanConfig() int {
-	if simd.ENABLED_EUCLIDEAN {
-		return EUCLIDEAN_WITH_SIMD
-	}
-
-	if noasm.ENABLED_EUCLIDEAN {
-		return EUCLIDEAN_WITH_NOASM
-	}
-
-	return EUCLIDEAN_WITH_PURE
-}
-
-const (
-	COSINE_WITH_PURE = iota
-	COSINE_WITH_NOASM
-	COSINE_WITH_SIMD
-)
-
-// Cosine Distance
-func Cosine() interface{ Distance(F32, F32) float32 } {
-	switch cosineConfig() {
-	case COSINE_WITH_PURE:
-		return pure.Cosine(0)
-	case COSINE_WITH_NOASM:
-		return noasm.Cosine(0)
-		// case COSINE_WITH_SIMD:
-		// 	return simd.Euclidean{}
-	}
-
-	return nil
+// Generic trait to  estimate "distance" between two vectors
+type Surface[Vector any] interface {
+	Distance(Vector, Vector) float32
 }
 
-func cosineConfig() int {
-	if simd.ENABLED_COSINE {
-		return COSINE_WITH_SIMD
-	}
+// From is a combinator that lifts V ⟼ V ⟼ float32 function to
+// an instance of Distance type trait
+type From[Vector any] func(Vector, Vector) float32
 
-	if noasm.ENABLED_COSINE {
-		return COSINE_WITH_NOASM
-	}
+func (f From[Vector]) Distance(a, b Vector) float32 { return f(a, b) }
 
-	return COSINE_WITH_PURE
+// ContraMap is a combinator that build a new instance of type trait Surface[V] using
+// existing instance of Distance[A] and f: b ⟼ a
+type ContraMap[A, B any] struct {
+	Surface[A]
+	pure.ContraMap[A, B]
 }
 
-const (
-	CONFIG_EUCLIDEAN = "euclidean"
-	CONFIG_COSINE    = "cosine"
-)
-
-// Info about config
-func Info() map[string]int {
-	info := map[string]int{}
-
-	info[CONFIG_EUCLIDEAN] = euclideanConfig()
-	info[CONFIG_COSINE] = cosineConfig()
-
-	return info
+// Distance implementation of contra variant functor
+func (f ContraMap[A, B]) Distance(a, b B) float32 {
+	return f.Surface.Distance(
+		f.ContraMap(a),
+		f.ContraMap(b),
+	)
 }
diff --git a/vector_test.go b/vector_test.go
@@ -18,21 +18,31 @@ import (
 	"github.com/kshard/vector/internal/simd"
 )
 
+//
+//
+//
+
+type Node struct {
+	ID     int
+	Vector vector.F32
+}
+
+func ntov(n Node) []float32 { return n.Vector }
+
 var (
-	n = 300
-	d float32
-	a vector.F32
-	b vector.F32
+	n  = 300
+	d  float32
+	a  vector.F32
+	b  vector.F32
+	n1 Node
+	n2 Node
 )
 
 func init() {
 	a = randF32()
 	b = randF32()
-
-	for i := 0; i < n; i++ {
-		a[i] = rand.Float32()
-		b[i] = rand.Float32()
-	}
+	n1 = Node{ID: 1, Vector: a}
+	n2 = Node{ID: 2, Vector: b}
 }
 
 func randF32() vector.F32 {
@@ -48,6 +58,10 @@ func equal(a, b float32) bool {
 	return -1e-4 < d && d < 1e-4
 }
 
+//
+//
+//
+
 func TestNoAsmEuclideanF32(t *testing.T) {
 	euc := pure.Euclidean(0)
 	sut := noasm.Euclidean(0)
@@ -84,6 +98,25 @@ func TestSIMDEuclideanF32(t *testing.T) {
 	}
 }
 
+func TestContraMapEuclidean(t *testing.T) {
+	euc := pure.Euclidean(0)
+	sut := vector.ContraMap[vector.F32, Node]{
+		Surface:   vector.Euclidean(),
+		ContraMap: func(n Node) []float32 { return n.Vector },
+	}
+
+	for i := 0; i < n*100; i++ {
+		a := randF32()
+		b := randF32()
+
+		g := euc.Distance(a, b)
+		d := sut.Distance(Node{Vector: a}, Node{Vector: b})
+		if !equal(d, g) {
+			t.Errorf("failed distance")
+		}
+	}
+}
+
 func TestNoAsmCosineF32(t *testing.T) {
 	euc := pure.Cosine(0)
 	sut := noasm.Cosine(0)
@@ -100,6 +133,10 @@ func TestNoAsmCosineF32(t *testing.T) {
 	}
 }
 
+//
+// Benchmark
+//
+
 func BenchmarkPureEuclideanF32(t *testing.B) {
 	euc := pure.Euclidean(0)
 
@@ -124,6 +161,17 @@ func BenchmarkSIMDEuclideanF32(t *testing.B) {
 	}
 }
 
+func BenchmarkContraMapEuclidean(t *testing.B) {
+	euc := vector.ContraMap[vector.F32, Node]{
+		Surface:   vector.Euclidean(),
+		ContraMap: ntov,
+	}
+
+	for i := t.N; i > 0; i-- {
+		d = euc.Distance(n1, n2)
+	}
+}
+
 func BenchmarkPureCosineF32(t *testing.B) {
 	cos := pure.Cosine(0)