CODEWITHSUNDEEP
c#multithreadingtask-parallel-library
user1737936
user1737936

Reputation: 55

Parallel.For Properties

public static void Main (string[] args)
        {
            int k = 0;
            int i = 3;
            var loopRes = Parallel.For (0, 20, (J) =>
            {
                k = i / J;
                Console.WriteLine ("Result After division " + J + " = " + k);
            }
            );

            if (loopRes.IsCompleted) {
                Console.WriteLine ("Loop was successful");
            }
            if (loopRes.LowestBreakIteration.HasValue) {
                Console.WriteLine ("loopRes.LowestBreakIteration.Value = " + loopRes.LowestBreakIteration.Value);
            }
        }

As of i read on the internet i can find 2 properties for Parallel.For & Parallel.Foreach

  1. IsCompleted
  2. LowestBreakIteration

For me first property is working fine. but when it comes to the situation where 3/0 then it will give the divided by zero error. so the second if loop should give me the number of LowestBreakIteration but it is throwing an error. please let me know if any body has come accross the same problem and solved it!!.

Also please explain what is the main purpose of those two properties. On what situations it wil be helpful.

Hope to hear from some one soon.

Upvotes: 3

Views: 267

Answers (2)

Mike Perrenoud
Mike Perrenoud

Reputation: 67898

It's because it's throwing an exception, change your loop just a tad:

public static void Main (string[] args) 
{ 
    int k = 0; 
    int i = 3; 
    var loopRes = Parallel.For (0, 20, (J, loopState) => 
    { 
        try { k = i / J; }
        catch { loopState.Break(); }
        Console.WriteLine ("Result After division " + J + " = " + k); 
    } 
    ); 

    if (loopRes.IsCompleted) { 
        Console.WriteLine ("Loop was successful"); 
    } 
    if (loopRes.LowestBreakIteration.HasValue) { 
        Console.WriteLine ("loopRes.LowestBreakIteration.Value = " + loopRes.LowestBreakIteration.Value); 
    } 
}

Upvotes: 1

Furqan Safdar
Furqan Safdar

Reputation: 16708

You can see how the maximum iteration number is affected by calls to the Break method by viewing the LowestBreakIteration property of the ParallelLoopState object, as shown below:

Parallel.For(1, 20, (i, pls) =>
{
    Console.WriteLine(string.Format(
        "i={0} LowestBreakIteration={1}", i, pls.LowestBreakIteration));
    if (i >= 15)
    {
        pls.Break();
    }
});

/* OUTPUT

i=10 LowestBreakIteration=
i=11 LowestBreakIteration=
i=19 LowestBreakIteration=
i=1 LowestBreakIteration=
i=2 LowestBreakIteration=19
i=3 LowestBreakIteration=19
i=6 LowestBreakIteration=19
i=7 LowestBreakIteration=19
i=8 LowestBreakIteration=19
i=9 LowestBreakIteration=19
i=12 LowestBreakIteration=19
i=13 LowestBreakIteration=19
i=14 LowestBreakIteration=19
i=15 LowestBreakIteration=19
i=4 LowestBreakIteration=19
i=5 LowestBreakIteration=15

*/

Reference: http://www.blackwasp.co.uk/ParallelLoopBreak_2.aspx

Upvotes: 0

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