mlemanczyk/even-perfect-numbers-scanner
1
0 Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Formatting

Browse Source
This commit is contained in:
Marek Lemańczyk committed 2025-09-24 18:20:55 +02:00
1 parent 3f010ce9ad
commit e92bca197d
1 file changed
+70 -70
Download Patch File Download Diff File Expand all files Collapse all files
PerfectNumbers.Core/MersenneDivisorCycles.cs
+70 -70
View File
@@ -150,85 +150,85 @@ public class MersenneDivisorCycles
private const int BufferSize10M = 10 * 1024 * 1024; private const int BufferSize10M = 10 * 1024 * 1024;
public static void Generate(string path, ulong maxDivisor, int threads = 16) public static void Generate(string path, ulong maxDivisor, int threads = 16)
{ {
// Binary-only generation of (divisor, cycle) pairs. CSV scaffolding removed. // Binary-only generation of (divisor, cycle) pairs. CSV scaffolding removed.
ulong start = 2; ulong start = 2;
ulong blockSize = maxDivisor / (ulong)threads + 1UL; ulong blockSize = maxDivisor / (ulong)threads + 1UL;
Task[] tasks = new Task[threads]; Task[] tasks = new Task[threads];
using Stream outputStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read, BufferSize10M, useAsync: false); using Stream outputStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read, BufferSize10M, useAsync: false);
// Start fresh to avoid mixing formats // Start fresh to avoid mixing formats
outputStream.SetLength(0L); outputStream.SetLength(0L);
outputStream.Position = 0L; outputStream.Position = 0L;
using var writer = new BinaryWriter(outputStream, Encoding.UTF8, leaveOpen: false); using var writer = new BinaryWriter(outputStream, Encoding.UTF8, leaveOpen: false);
for (var taskIndex = 0; taskIndex < threads; taskIndex++) for (var taskIndex = 0; taskIndex < threads; taskIndex++)
{ {
ulong threadStart = start + (ulong)taskIndex * blockSize; ulong threadStart = start + (ulong)taskIndex * blockSize;
if (threadStart > maxDivisor) if (threadStart > maxDivisor)
{ {
tasks[taskIndex] = Task.CompletedTask; tasks[taskIndex] = Task.CompletedTask;
continue; continue;
} }
ulong threadEnd = threadStart + blockSize - 1UL; ulong threadEnd = threadStart + blockSize - 1UL;
if (threadEnd > maxDivisor) if (threadEnd > maxDivisor)
{ {
threadEnd = maxDivisor; threadEnd = maxDivisor;
} }
ulong localStart = threadStart; ulong localStart = threadStart;
ulong localEnd = threadEnd; ulong localEnd = threadEnd;
tasks[taskIndex] = Task.Run(() => tasks[taskIndex] = Task.Run(() =>
{ {
ulong rangeLength = localEnd - localStart + 1UL; ulong rangeLength = localEnd - localStart + 1UL;
(ulong divisor, ulong cycle)[] localCycles = ArrayPool<(ulong, ulong)>.Shared.Rent(checked((int)rangeLength)); (ulong divisor, ulong cycle)[] localCycles = ArrayPool<(ulong, ulong)>.Shared.Rent(checked((int)rangeLength));
int localCycleIndex = 0; int localCycleIndex = 0;
try try
{ {
for (ulong divisor = localStart; divisor <= localEnd; divisor++) for (ulong divisor = localStart; divisor <= localEnd; divisor++)
{ {
if ((divisor & 1UL) == 0UL) if ((divisor & 1UL) == 0UL)
{ {
continue; continue;
} }
if ((divisor % 3UL) == 0UL || (divisor % 5UL) == 0UL || (divisor % 7UL) == 0UL || (divisor % 11UL) == 0UL) if ((divisor % 3UL) == 0UL || (divisor % 5UL) == 0UL || (divisor % 7UL) == 0UL || (divisor % 11UL) == 0UL)
{ {
continue; continue;
} }
ulong cycle = CalculateCycleLength(divisor); ulong cycle = CalculateCycleLength(divisor);
localCycles[localCycleIndex++] = (divisor, cycle); localCycles[localCycleIndex++] = (divisor, cycle);
} }
if (localCycleIndex == 0) if (localCycleIndex == 0)
{ {
return; return;
} }
lock (writer) lock (writer)
{ {
writer.BaseStream.Position = writer.BaseStream.Length; writer.BaseStream.Position = writer.BaseStream.Length;
for (int i = 0; i < localCycleIndex; i++) for (int i = 0; i < localCycleIndex; i++)
{ {
(ulong divisor, ulong cycle) = localCycles[i]; (ulong divisor, ulong cycle) = localCycles[i];
writer.Write(divisor); writer.Write(divisor);
writer.Write(cycle); writer.Write(cycle);
} }
writer.Flush(); writer.Flush();
} }
} }
finally finally
{ {
ArrayPool<(ulong, ulong)>.Shared.Return(localCycles, clearArray: false); ArrayPool<(ulong, ulong)>.Shared.Return(localCycles, clearArray: false);
} }
}); });
} }
Task.WaitAll(tasks); Task.WaitAll(tasks);
} }
public static void GenerateGpu(string path, ulong maxDivisor, int batchSize = 1_000_000, long skipCount = 0L, long nextPosition = 0L) public static void GenerateGpu(string path, ulong maxDivisor, int batchSize = 1_000_000, long skipCount = 0L, long nextPosition = 0L)
{ {