/// <summary>
/// Creates an asynchronous computation that executes all the given asynchronous computations, initially queueing each as work items and using a fork/join pattern.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="ms"></param>
/// <returns></returns>
public static Async <ImmutableList <T> > Parallel <T>(this ImmutableList <Async <T> > ms)
{
var empty = new ImmutableList <T>();
return(() =>
{
var num = (uint)Math.Min(8, ms.Count); // 64 is maximum here
if (num == 0)
{
return empty;
}
var xs = ms.Take(num);
var rest = ms.RemoveRange(0, (int)num);
var asyncs = xs.Map(x =>
{
var handle = new AsyncEventHandle <T>();
x.Bind <T, Unit>(v => () => handle.Complete(v)).Start();
return handle;
});
WaitHandle.WaitAll(asyncs.Map(ah => (WaitHandle)ah.DoneEvent).ToArray());
var ps = asyncs.Map(x => x.Result());
return empty.AddRange(rest.Count > 0 ? ps.AddRange(rest.Parallel().RunSynchronously()) : ps);
});
}
/// <summary>
/// Starts a child computation. This allows multiple asynchronous computations to be executed simultaneously.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="m"></param>
/// <returns>A new computation that waits for the input computation to finish.</returns>
public static Async <Async <T> > StartChild <T>(this Async <T> m)
{
return(() =>
{
var handle = new AsyncEventHandle <T>();
m.StartAndReply(ch => new AsyncReplyChannel <T>(r =>
{
ch.Reply(r);
handle.Complete(r);
return Unit.Default;
}));
return () =>
{
handle.DoneEvent.WaitOne();
return handle.Result();
};
});
}
/// <summary>
/// Creates an asynchronous computation that executes all the given asynchronous computations, initially queueing each as work items and using a fork/join pattern.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="ms"></param>
/// <returns></returns>
public static Async <IEnumerable <T> > Parallel <T>(this IEnumerable <Async <T> > ls)
{
return(() =>
{
var ms = System.Collections.Immutable.ImmutableList.ToImmutableList(ls);
var num = Math.Min(8, ms.Count); // 64 is maximum here
if (num == 0)
{
return System.Collections.Immutable.ImmutableList <T> .Empty;
}
var xs = ms.GetRange(0, num);
var rest = ms.RemoveRange(0, num);
var asyncs = xs.Select(x =>
{
var handle = new AsyncEventHandle <T>();
x.Bind <T, Unit>(v => () => handle.Complete(v)).Start();
return handle;
}).ToImmutableList();
WaitHandle.WaitAll(asyncs.Select(ah => (WaitHandle)ah.DoneEvent).ToArray());
var ps = asyncs.Select(x => x.Result());
return System.Collections.Immutable.ImmutableList <T> .Empty.AddRange(ps).AddRange(rest.Parallel().RunSynchronously());
});
}