Parallel.For interruption

Question

Suppose you have an array of 1000 random integer numbers and you need to loop over it to find the number 68 for example.

Using the new Parallel.For on a quad core CPU would improve speed considerably, making each core to work only 250 array items.

The question is: is it possible to interrupt the Parallel.For loop when the following condition is met?

if (integerArray[i] == 68)

   break;

Thanks.

Insomniac

Answer 1

If you want to stop after the current executing iteration are done (but iterations before the current WILL be executed - that is, the iterations with a lower index = i)

Parallel.For(0, 100, (i, s) =>
    {
        s.Break();
    });

or if you want to stop after the current and interations before this (in terms of index = i) should also stop

Parallel.For(0, 100, (i, s) =>
    {
        s.Stop();
    });

but in BOTH cases it is good practice to check if the work should be aborted if the iteration can take a while

s.ShouldExitCurrentIteration

read more here Parallel.For Method (Int32, Int32, Action(Int32, ParallelLoopState))

Abshire

I mixed up some notion about Break and Stop - please reread the answer :) – Abshire

Answer 2

It sounds to me that you should look into PLINQ (Parallel LINQ) to execute a parallel query, rather than a parallel for.
http://msdn.microsoft.com/en-us/library/dd460688.aspx

Roxana

Correct for this (simple) example. But it is a more general question. – Treble