Parallel Extensions

Arjun Panwar

15y2kAzure

Parallel Extensions in .NET 4.0

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
Accepted answer
Here's a very simple example of using Parallel.For and Parallel.ForEach. In practice, of course, this would only be worth doing for a large array:

using System;
using System.Threading.Tasks;

class Test
{
static void Main()
{
int[] ia = new int[20];
Initialize(ia);

// non-parallel loop

for(int i = 0; i < 20; i++) Doubler(ref ia[i]);

PrintArray(ia);

// parallel for loop

Initialize(ia);

Parallel.For(0, 20, i => Doubler(ref ia[i]));

PrintArray(ia);

// parallel foreach loop

Initialize(ia);

Parallel.ForEach(ia, i => Doubler(ref ia[i]));

PrintArray(ia);

Console.ReadKey();
}

static void Initialize(int[] ia)
{
for(int i = 0; i < ia.Length; i++) ia[i] = i;
}

static void Doubler(ref int i)
{
i = 2 * i;
}

static void PrintArray(int[] ia)
{
foreach(int i in ia) Console.Write("{0} ", i);
Console.WriteLine();
}

}

Notice that the second argument of Parallel.For is the 'exclusive' end index of the iteration. So to iterate from 0 to 19, you need to specify arguments of 0 and 20.
Arjun Panwar15y ago
hi,
Thanks Vulpes
Arjun Panwar15y ago
how to perform Parallel.For and Parallel.ForEach in .Net 4.0.
Arjun Panwar15y ago
how to perform Parallel.For and Parallel.ForEach in .Net 4.0.
Sam Hobbs15y ago
Is this a question? If you want to know what it is, then I hope these help. I found them easily by doing a MSDN search. As Vulpes indicates, there are articles in this web site that will help. If you read the MSDN articles then you will know what to look for in the articles here.
Vulpes15y ago
Whatever the problem is, there's plenty of material to look at in our 'Recommended Articles' in the sidebar to the right of this thread.
Akash Ahlawat15y ago
What problem u r facing in it??