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@sirupsen
Created Jul 4, 2022
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package main
import (
"math/rand"
"sync"
)
type Cell88 struct {
padding [80]byte
value float64
}
type Cell64 struct {
padding [56]byte
value float64
}
type Cell32 struct {
padding [24]byte
value float64
}
type Cell16 struct {
padding [8]byte
value float64
}
type Cell8 struct {
value float64
}
type Cell = Cell8
func main() {
// pointerMapIntegerIndex(10_000_000)
// pointerMapIntegerIndexPreallocated(10_000_000)
// arrayCellValues(10_000_000)
// parallelArrayCellValues(333_333_333)
parallelArrayCellValuesWithOwnership(10_000_000)
}
func pointerMapIntegerIndex(nCells int) {
one := make(map[int]*Cell, nCells)
two := make(map[int]*Cell, nCells)
res := make(map[int]*Cell, nCells)
rand := rand.New(rand.NewSource(0xCA0541))
for i := 0; i < nCells; i++ {
one[i] = &Cell{value: rand.Float64()}
two[i] = &Cell{value: rand.Float64()}
}
for i := 0; i < nCells; i++ {
res[i] = &Cell{value: one[i].value * two[i].value}
}
}
func pointerMapIntegerIndexPreallocated(nCells int) {
oneCells := make([]Cell, nCells)
twoCells := make([]Cell, nCells)
resCells := make([]Cell, nCells)
one := make(map[int]*Cell, nCells)
two := make(map[int]*Cell, nCells)
res := make(map[int]*Cell, nCells)
rand := rand.New(rand.NewSource(0xCA0541))
for i := 0; i < nCells; i++ {
oneCells[i].value = rand.Float64()
twoCells[i].value = rand.Float64()
one[i] = &oneCells[i]
two[i] = &twoCells[i]
}
for i := 0; i < nCells; i++ {
resCells[i].value = one[i].value * two[i].value
res[i] = &resCells[i]
}
}
func arrayCellValues(nCells int) {
one := make([]Cell, nCells)
two := make([]Cell, nCells)
res := make([]Cell, nCells)
rand := rand.New(rand.NewSource(0xCA0541))
for i := 0; i < nCells; i++ {
one[i].value = rand.Float64()
two[i].value = rand.Float64()
}
for i := 0; i < nCells; i++ {
res[i].value = one[i].value * two[i].value
}
}
func parallelArrayCellValues(nCells int) {
one := make([]Cell, nCells)
two := make([]Cell, nCells)
res := make([]Cell, nCells)
nThreads := 1
var wg sync.WaitGroup
for i := 0; i < nCells; i += nCells / nThreads {
wg.Add(1)
go func(i int) {
defer wg.Done()
rand := rand.New(rand.NewSource(0xCA0541))
end := i + nCells / nThreads
if (end > nCells) {
end = nCells
}
for j := i; j < end; j++ {
one[j].value = rand.Float64()
two[j].value = rand.Float64()
}
for j := i; j < i + nCells / nThreads; j++ {
res[j].value = one[j].value * two[j].value
}
}(i)
}
wg.Wait()
}
func parallelArrayCellValuesWithOwnership(nCells int) {
nThreads := 8
var wg sync.WaitGroup
resCh := make(chan []Cell)
for i := 0; i < nCells; i += nCells / nThreads {
wg.Add(1)
go func() {
wg.Done()
one := make([]Cell, nCells / nThreads)
two := make([]Cell, nCells / nThreads)
res := make([]Cell, nCells / nThreads)
rand := rand.New(rand.NewSource(0xCA0541))
for j := 0; j < nCells / nThreads; j++ {
one[j].value = rand.Float64()
two[j].value = rand.Float64()
}
for j := 0; j < nCells / nThreads; j++ {
res[j].value = one[j].value * two[j].value
}
resCh <- res
}()
}
wg.Wait()
<-resCh
<-resCh
<-resCh
<-resCh
}
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