sort_benchmark_test.go

Documentation: slices

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package slices_test
     6  
     7  import (
     8  	"cmp"
     9  	"fmt"
    10  	"slices"
    11  	"strings"
    12  	"testing"
    13  )
    14  
    15  func BenchmarkBinarySearchFloats(b *testing.B) {
    16  	for _, size := range []int{16, 32, 64, 128, 512, 1024} {
    17  		b.Run(fmt.Sprintf("Size%d", size), func(b *testing.B) {
    18  			floats := make([]float64, size)
    19  			for i := range floats {
    20  				floats[i] = float64(i)
    21  			}
    22  			midpoint := len(floats) / 2
    23  			needle := (floats[midpoint] + floats[midpoint+1]) / 2
    24  			b.ResetTimer()
    25  			for i := 0; i < b.N; i++ {
    26  				slices.BinarySearch(floats, needle)
    27  			}
    28  		})
    29  	}
    30  }
    31  
    32  type myStruct struct {
    33  	a, b, c, d string
    34  	n          int
    35  }
    36  
    37  func BenchmarkBinarySearchFuncStruct(b *testing.B) {
    38  	for _, size := range []int{16, 32, 64, 128, 512, 1024} {
    39  		b.Run(fmt.Sprintf("Size%d", size), func(b *testing.B) {
    40  			structs := make([]*myStruct, size)
    41  			for i := range structs {
    42  				structs[i] = &myStruct{n: i}
    43  			}
    44  			midpoint := len(structs) / 2
    45  			needle := &myStruct{n: (structs[midpoint].n + structs[midpoint+1].n) / 2}
    46  			cmpFunc := func(a, b *myStruct) int { return a.n - b.n }
    47  			b.ResetTimer()
    48  			for i := 0; i < b.N; i++ {
    49  				slices.BinarySearchFunc(structs, needle, cmpFunc)
    50  			}
    51  		})
    52  	}
    53  }
    54  
    55  func BenchmarkSortFuncStruct(b *testing.B) {
    56  	for _, size := range []int{16, 32, 64, 128, 512, 1024} {
    57  		b.Run(fmt.Sprintf("Size%d", size), func(b *testing.B) {
    58  			structs := make([]*myStruct, size)
    59  			for i := range structs {
    60  				structs[i] = &myStruct{
    61  					a: fmt.Sprintf("string%d", i%10),
    62  					n: i * 11 % size,
    63  				}
    64  			}
    65  			cmpFunc := func(a, b *myStruct) int {
    66  				if n := strings.Compare(a.a, b.a); n != 0 {
    67  					return n
    68  				}
    69  				return cmp.Compare(a.n, b.n)
    70  			}
    71  			// Presort the slice so all benchmark iterations are identical.
    72  			slices.SortFunc(structs, cmpFunc)
    73  			b.ResetTimer()
    74  			for i := 0; i < b.N; i++ {
    75  				// Sort the slice twice because slices.SortFunc modifies the slice in place.
    76  				slices.SortFunc(structs, func(a, b *myStruct) int { return cmpFunc(b, a) })
    77  				slices.SortFunc(structs, cmpFunc)
    78  			}
    79  		})
    80  	}
    81  }
    82
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