using System;

using System.Linq;

using System.Collections.Concurrent;

using System.Threading.Tasks;

using System.Threading;

using System.Diagnostics;

​

const Int32 bits = 100_000_000;

const Int32 n = bits/32;

Int32[] x =  new Int32[n]; 

Int32[] y =  new Int32[n]; 

Random random = new Random();

Int32 countOnes = 0;

Int32 countOnesZip = 0;

Int32 countOnesPar = 0;

Int32 countOnesTask = 0;

​

Int32[] split = new int[Environment.ProcessorCount];

Task[] tasks = new Task[split.Length];

Int32 take = (int)Math.Round((double)x.Length / tasks.Length, MidpointRounding.AwayFromZero);

​

for (int i = 0; i < n; i++)

{

    x[i] = random.Next();

    y[i] = random.Next();

 }

​

Stopwatch stopwatch = Stopwatch.StartNew();

for (int i = 0; i < n; i++) { 

    countOnes += Int32.PopCount( x[i] & y[i]); 

}

stopwatch.Stop(); long elapsed = stopwatch.ElapsedMilliseconds;

​

stopwatch.Restart();

foreach( var (a,b) in x.Zip(y) ) { 

    countOnesZip += Int32.PopCount( a & b); 

}

stopwatch.Stop(); long elapsed_zip = stopwatch.ElapsedMilliseconds;

​

stopwatch.Restart();

Partitioner<Tuple<int, int>> partitioner = Partitioner.Create(0, n);

Parallel.ForEach(partitioner, range =>

{

    int startIndex = range.Item1;

    int endIndex = range.Item2;

    int localCountOnes = 0;

​

    for (int i = startIndex; i < endIndex; i++)

    {

        localCountOnes += Int32.PopCount(x[i] & y[i]);

    }

​

    Interlocked.Add(ref countOnesPar, localCountOnes);

});

​

stopwatch.Stop(); long elapsed_par = stopwatch.ElapsedMilliseconds;

​

stopwatch.Restart();

for (var i = 0; i < tasks.Length; i++)

{

    var taskNumber = i;

    tasks[i] = Task.Run(() =>

    {

        var localCount = 0; 

        for (var index = taskNumber * take; index < (taskNumber + 1) * take && index < x.Length; index++)

        {

            localCount += int.PopCount(x[index] & y[index]);

        }

​

        split[taskNumber] = localCount;

    });

}

await Task.WhenAll(tasks);

countOnesTask = split.Sum();

stopwatch.Stop(); long elapsed_task = stopwatch.ElapsedMilliseconds;

​

​

Console.WriteLine($"Processed {bits:N0} bits");

Console.WriteLine($"Elapsed time (For): {elapsed,18}ms Count: {countOnes:N0}");

Console.WriteLine($"Elapsed time (Parallel Tasks): {elapsed_task,7}ms Count: {countOnesTask:N0}");

Console.WriteLine($"Elapsed time (Parallel.ForEach): {elapsed_par,5}ms Count: {countOnesPar:N0}");

Console.WriteLine($"Elapsed time (Linq ForEach): {elapsed_zip,9}ms Count: {countOnesZip:N0}");

​

​

​