84
edits
Changes
→Implementation
'''Multi-Thread Program in Go'''
package main
import (
"bufio"
"fmt"
"log"
"os"
"runtime"
"runtime/debug"
"strconv"
"strings"
"sync"
"time"
)
func multiply(A [][]int, B [][]int) [][]int { sizeA := len(A)
sizeB := len(B)
n := make([][]int, sizeA)
for i := range n {
n[i] = make([]int, sizeB)
}
for i := 0; i < sizeA; i++ {
for k := 0; k < sizeB; k++ {
temp := A[i][k]
for j := 0; j < sizeB; j++ {
n[i][j] += temp * B[k][j]
}
}
}
return n
}
func splitMatrix(nrOfThreads int, matrix [][]int) (matrixes [][][]int) {
splitter := len(matrix) / nrOfThreads
for i := 0; i < nrOfThreads; i++ {
matrixes = append(matrixes, matrix[splitter*i:(splitter*(i+1))])
}
return
}
func multiplyStuff(finalMatrix *[][][]int, matrix1 [][]int, matrix2 [][]int, i int) {
(*finalMatrix)[i] = multiply(matrix1, matrix2)
}
func readFile(filePath string) (matrix1 [][]int, matrix2 [][]int) {
file, err := os.Open(filePath)
if err != nil {
log.Fatal(err)
}
defer file.Close()
var temp []int
matrixNr := 1
scanner := bufio.NewScanner(file)
for scanner.Scan() {
words := strings.Fields(scanner.Text())
if len(words) != 0 {
for _, element := range words {
i, err := strconv.Atoi(element)
if err != nil {
log.Fatal(err)
}
temp = append(temp, i)
}
if matrixNr == 1 {
matrix1 = append(matrix1, temp)
} else {
matrix2 = append(matrix2, temp)
}
temp = nil
} else {
matrixNr = 2
}
}
if err := scanner.Err(); err != nil {
log.Fatal(err)
}
return
}
func main() {
file := os.Args[1]
nrOfThreads, err := strconv.Atoi(os.Args[2])
if err != nil {
log.Fatal("USAGE: " + os.Args[0] + " <file> <nrOfThreads>")
}
debug.SetGCPercent(-1)
if nrOfThreads <= 0 {
runtime.GOMAXPROCS(1)
} else if nrOfThreads >= 16 {
runtime.GOMAXPROCS(8)
} else {
runtime.GOMAXPROCS(nrOfThreads)
}
var wg sync.WaitGroup
finishedMatrix := make([][][]int, nrOfThreads)
matrix1, matrix2 := readFile(file)
if len(matrix1) != len(matrix2) || (nrOfThreads != 0 && len(matrix1)%nrOfThreads != 0) {
log.Fatal("USAGE: " + os.Args[0] + " <file> <nrOfThreads>")
}
var start int64
if nrOfThreads == 0 {
start = time.Now().UnixNano()
multiply(matrix1, matrix2)
} else {
matrixes := splitMatrix(nrOfThreads, matrix1)
start = time.Now().UnixNano()
for i := 0; i < nrOfThreads; i++ {
wg.Add(1)
go func(index int) {
defer wg.Done()
multiplyStuff(&finishedMatrix, matrixes[index], matrix2, index)
}(i)
}
wg.Wait()
}
end := time.Now().UnixNano()
fmt.Printf("Execution took %d ns\n", (end - start))
runtime.GC()
}
