private static void Main(string[] args)
{
var random = new Random();
var matrix1 = new FlatMatrix <int>(MatrixSize, MatrixSize);
var matrix2 = new FlatMatrix <int>(MatrixSize, MatrixSize);
for (uint i = 0; i < MatrixSize * MatrixSize; i++)
{
matrix1[i] = random.Next(MatrixMin, MatrixMax + 1);
matrix2[i] = random.Next(MatrixMin, MatrixMax + 1);
}
var stopwatch = new Stopwatch();
stopwatch.Start();
FlatMatrix <int> result = Matrix.Dot(matrix1, matrix2);
// FlatMatrix<int> result = Matrix.DotPool(matrix1, matrix2);
stopwatch.Stop();
Console.WriteLine(matrix1);
Console.WriteLine(matrix2);
Console.WriteLine(result);
Console.WriteLine($"Elapsed: {stopwatch.ElapsedMilliseconds}ms");
}
public static FlatMatrix <int> Dot(FlatMatrix <int> a, FlatMatrix <int> b)
{
Debug.Assert(a.Width == b.Height);
var result = new FlatMatrix <int>(b.Width, a.Height);
uint length = result.Height * result.Width;
uint jobsPerThread = length / ThreadCount;
var threads = new Thread[ThreadCount];
for (uint i = 0; i < ThreadCount; i++)
{
uint i1 = i;
threads[i] = new Thread(_ =>
{
uint start = i1 * jobsPerThread;
uint count = Math.Min(jobsPerThread, length - start - 1);
IEnumerable <uint> indices = Enumerable.Range((int)start, (int)count)
.Select(index => (uint)index);
DotTask(a, b, indices, result);
});
}
foreach (Thread thread in threads)
{
thread.Start();
}
foreach (Thread thread in threads)
{
thread.Join();
}
return(result);
}
public static FlatMatrix <int> DotPool(FlatMatrix <int> a, FlatMatrix <int> b)
{
Debug.Assert(a.Width == b.Height);
var result = new FlatMatrix <int>(b.Width, a.Height);
uint length = result.Height * result.Width;
uint jobsPerThread = length / ThreadCount;
var doneEvents = new ManualResetEvent[ThreadCount];
for (uint i = 0; i < ThreadCount; i++)
{
uint i1 = i;
doneEvents[i] = new ManualResetEvent(false);
ThreadPool.QueueUserWorkItem(_ =>
{
uint start = i1 * jobsPerThread;
uint count = Math.Min(jobsPerThread, length - start - 1);
IEnumerable <uint> indices = Enumerable.Range((int)start, (int)count)
.Select(index => (uint)index);
DotTask(a, b, indices, result);
doneEvents[i1].Set();
});
}
WaitHandle.WaitAll(doneEvents);
return(result);
}
private static void DotTask(FlatMatrix <int> a, FlatMatrix <int> b, IEnumerable <uint> indices, FlatMatrix <int> result)
{
IEnumerable <(uint, uint, uint)> indices2D = indices.Select(index =>
{
(uint x, uint y) = result.Index2D(index);
return(index, x, y);
});
foreach ((uint index, uint x, uint y) in indices2D)
{
var aColumn = new List <int>((int)result.Height);
var bRow = new List <int>((int)result.Width);
for (uint i = 0; i < a.Height; i++)
{
aColumn.Add(a[x, i]);
}
for (uint i = 0; i < b.Width; i++)
{
bRow.Add(b[i, y]);
}
result[index] = Vector.Dot(aColumn, bRow);
}
}
