Gecko [ 167.86.127.34 ]

Name	Size	Permission
doubleselect.go	1.96 KB	-rw-r--r--
fifo.go	896 B	-rw-r--r--
goroutines.go	743 B	-rw-r--r--
nonblock.go	3.93 KB	-rw-r--r--
perm.go	1.33 KB	-rw-r--r--
powser1.go	12.65 KB	-rw-r--r--
powser2.go	13.29 KB	-rw-r--r--
select.go	913 B	-rw-r--r--
select2.go	1.04 KB	-rw-r--r--
select3.go	4.07 KB	-rw-r--r--
select4.go	513 B	-rw-r--r--
select5.go	9.97 KB	-rw-r--r--
select6.go	783 B	-rw-r--r--
select7.go	932 B	-rw-r--r--
select8.go	826 B	-rw-r--r--
sendstmt.go	672 B	-rw-r--r--
sieve1.go	1.49 KB	-rw-r--r--
sieve2.go	3.88 KB	-rw-r--r--
zerosize.go	349 B	-rw-r--r--

Code Editor : sieve1.go

// run

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Test concurrency primitives: classical inefficient concurrent prime sieve.

// Generate primes up to 100 using channels, checking the results.
// This sieve consists of a linear chain of divisibility filters,
// equivalent to trial-dividing each n by all primes p ≤ n.

package main

// Send the sequence 2, 3, 4, ... to channel 'ch'.
func Generate(ch chan<- int) {
	for i := 2; ; i++ {
		ch <- i // Send 'i' to channel 'ch'.
	}
}

// Copy the values from channel 'in' to channel 'out',
// removing those divisible by 'prime'.
func Filter(in <-chan int, out chan<- int, prime int) {
	for i := range in { // Loop over values received from 'in'.
		if i%prime != 0 {
			out <- i // Send 'i' to channel 'out'.
		}
	}
}

// The prime sieve: Daisy-chain Filter processes together.
func Sieve(primes chan<- int) {
	ch := make(chan int) // Create a new channel.
	go Generate(ch)      // Start Generate() as a subprocess.
	for {
		// Note that ch is different on each iteration.
		prime := <-ch
		primes <- prime
		ch1 := make(chan int)
		go Filter(ch, ch1, prime)
		ch = ch1
	}
}

func main() {
	primes := make(chan int)
	go Sieve(primes)
	a := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}
	for i := 0; i < len(a); i++ {
		if x := <-primes; x != a[i] {
			println(x, " != ", a[i])
			panic("fail")
		}
	}
}

${this.title}

Code Editor : sieve1.go