using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
namespace FastLoopingConsole
{
class Program
{
static void Main(string[] args)
{
Stopwatch sw = new Stopwatch();
long MaxNumber = 2500000000;
/////////////////////////////////////////////////////////////
long sum = 0;
sw.Restart();
sum = 0;
Parallel.For(0, MaxNumber, (i) =>
{
Interlocked.Add(ref sum, (long) Math.Sqrt(i));
});
sw.Stop();
Trace.WriteLine($"Method_1 (Parallel.For): Sum = {sum}");
Trace.WriteLine($"Elapsed time {sw.Elapsed}");
/////////////////////////////////////////////////////////////
sw.Restart();
sum = 0;
var partinioner = Partitioner.Create(0, MaxNumber);
Parallel.ForEach(partinioner, (range) =>
{
long partialSum = 0;
for (long i = range.Item1; i < range.Item2; i++)
{
partialSum += (long)Math.Sqrt(i);
}
Interlocked.Add(ref sum, partialSum);
});
sw.Stop();
Trace.WriteLine($"Method_2 (Parallel.Foreach with partinioner): Sum = {sum}");
Trace.WriteLine($"Elapsed time {sw.Elapsed}");
/////////////////////////////////////////////////////////////
sw.Restart();
sum = 0;
for (long i = 0; i < MaxNumber; i++)
{
sum += (long)Math.Sqrt(i);
};
sw.Stop();
Trace.WriteLine($"Method_3 (Naive For): Sum = {sum}");
Trace.WriteLine($"Elapsed time {sw.Elapsed}");
}
}
}
Results:
Method_1 (Parallel.For): Sum = 59627479402839 Elapsed time 00:00:47.4136964 Method_2 (Parallel.Foreach with partinioner): Sum = 59627479402839 Elapsed time 00:00:02.2316763 Method_3 (Naive For): Sum = 59627479402839 Elapsed time 00:00:04.1533972
