Logo

Programming-Idioms

Fork-join : launch the concurrent execution of procedure f with parameter i from 1 to 1000.
Tasks are independent and f(i) doesn't return any value.
Tasks need not run all at the same time, so you may use a pool.
Wait for the completion of the 1000 tasks and then print "Finished".
New implementation

Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating material.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations
using System.Threading.Tasks;
using System.Linq;
await Task.WhenAll(Enumerable.Range(0, 1000).Select(i => Task.Run(() => f(i))));
Console.WriteLine("Finished");

static async Task f(int value)
{
    // Do something with value. Delay to simulate work
    await Task.Delay(500);
}
using System.Threading.Tasks;
int numTasks = 1000;
Task<int>[] output = new System.Threading.Tasks.Task<int>[numTasks];
for (int i = 0; i < numTasks; i++)
{
  output[i] = Task.Factory.StartNew(
                   new Func <object, int>(LongRunningOperation), 2000);
}
Task.WaitAll(output);

int LongRunningOperation(object objMs)
{
  int ms = (int)objMs;
  Thread.Sleep(ms);
  return ms;
}
import std.stdio;
import std.parallelism;
import std.range;
foreach(i; parallel(iota(1,1001))){
	f(i);
}
writeln("Finished");
import 'dart:isolate';
List<Future> tasks = [];
for (int i = 1; i <= 1000; i++) {
  tasks.add(Isolate.spawn(f, i));
}
await Future.wait(tasks);
print("finished");
# 1
f = &(IO.puts(&1)) 

# 2
printTimes = &(for n <- 1..&1, do: spawn(fn -> f.(n) end))

# 3
fn -> printTimes.(1000) end |> Task.async |> Task.await
IO.puts("Finished")
 
run_n_times(Fun, N) ->
    Self = self(),
    Task = fun (I) -> spawn(?MODULE, run_task_and_notify_completion, [Self, Fun, I]) end,
    lists:foreach(Task, lists:seq(1, N)),
    wait_for_n_tasks(N).

run_task_and_notify_completion(ParentPid, Fun, Arg) ->
    Fun(Arg),
    ParentPid ! done.

wait_for_n_tasks(0) ->
    io:format("Finished~n");
wait_for_n_tasks(N) when N > 0 ->
    receive
        done ->
            ok
    end,
    wait_for_n_tasks(N-1).

run_n_times(F, 1000).
  integer :: tasks, n, t, i
  tasks = 1000
  n = num_images()
  t = this_image()
  do i = t, tasks, n
     call f(i)
  end do
  sync all
  print *,"Finished"
import "sync"
var wg sync.WaitGroup
wg.Add(1000)
for i := 1; i <= 1000; i++ {
	go func(i int) {
		f(i)
		wg.Done()
	}(i)
}
wg.Wait()
fmt.Println("Finished")
import "async" Control.Concurrent.Async
mapConcurrently f [1..1000]
print "Finished"
{
  // in file worker.js
  onmessage = f
}
{
  // in file main.js
  for (let i = 0; i < 1000; i++) {
    new Worker ('worker.js')
      .postMessage (i)
  }
}
const tasks = [];
for (let i = 0; i < 1000; i++) {
  tasks.push(f(i));
}

await Promise.all(tasks);
console.log("Finished");
import java.util.concurrent.*;
ExecutorService executor = Executors.newFixedThreadPool(4);
for (int i = 1; i <= 1000; i++) {
	Task task = new Task(i);
	executor.submit(() -> f(i));
}
executor.awaitTermination(10L, TimeUnit.MINUTES);
System.out.println("Finished");
import java.util.concurrent.*;
class Task implements Runnable {
	int i;
	Task(int i) {
		this.i = i;
	}
	@Override
	public void run() {
		f(i);
	}
}

ExecutorService executor = Executors.newFixedThreadPool(4);
for (int i = 1; i <= 1000; i++) {
	Task task = new Task(i);
	executor.submit(task);
}
executor.shutdown();
executor.awaitTermination(10L, TimeUnit.MINUTES);
System.out.println("Finished");
import kotlinx.coroutines.*
(1..1000)
    .map { i ->
        CoroutineScope(Dispatchers.Default).async {
            f(i)
        }
    }
    .awaitAll()
print("Finished")
(ql:quickload :lparallel)
(use-package :lparallel)
(lambda (fn)
  (pdotimes (i 1000)
    (funcall fn i)))
use threads;
for my $i (1 .. 1000) {
    threads->create('f', $i);
}
sleep 3 while threads->list(threads::running);
print "Finished\n";

# optional: threads library wants you to explicitly join or detach
# your threads before exiting program.
$_->join() for threads->list(threads::joinable);
from multiprocessing import Pool
def f(i):
	i * i

with Pool(1000) as p:
	p.map(func=f, iterable=range(1, 1001))

print('Finished')
threads = 1000.times.map do |i|
  Thread.new { f(i) }
end
threads.join
use std::thread;
let threads: Vec<_> = (0..1000).map(|i| thread::spawn(move || f(i))).collect();

for t in threads {
	t.join();
}