package main 
import (
        "fmt"
        "runtime"
)
 
//并發(fā)和并行
var quit chan int = make(chan int) 
func loop() {
        for i := 0; i < 100; i++ { //為了觀察，跑多些
                fmt.Printf("%d ", i)
        }
        quit <- 0
}
 
func main() {
        runtime.GOMAXPROCS(2) // 最多使用2個核
 
        go loop()
        go loop()
 
        for i := 0; i < 2; i++ {
                <- quit
        }
}

package main
import (
	"fmt"
	"runtime"
)
type Vector []float64
func (v Vector) DoSome(p, i, n int, u Vector, c chan int) {
	sum := 0.0
	for ; i < n; i++ {
		sum += u[i]
	}
	v[p] = sum
	c <- 1
}
const NCPU = 4
func (v Vector) DoAll(u Vector) {
	c := make(chan int, NCPU)
	for i := 0; i < NCPU; i++ {
		fmt.Println(i, i*len(u)/NCPU, (i+1)*len(u)/NCPU)
		go v.DoSome(i, i*len(u)/NCPU, (i+1)*len(u)/NCPU, u, c)
	}
	for i := 0; i < NCPU; i++ {
		<-c
	}
	sum := 0.0
	for _, value := range v {
		sum += value
	}
	fmt.Println(sum)
}
func main() {
	u := make([]float64, 64)
	for i := 0; i < 64; i++ {
		u[i] = float64(i)
	}
	var v Vector = make([]float64, NCPU)
	v.DoAll(u)
	ncpu := runtime.NumCPU()
	fmt.Println(ncpu)
}