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Merge pull request #64 from mlemanczyk/codex/analyze-optimization-paths-for-evenperfectbitscanner

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Make by-divisor divisor cycle filtering optional
This commit is contained in:
Marek Lemańczyk authored and GitHub committed 2025-09-22 16:42:43 +02:00
2 parents 0195960b5a 378d6a2fd8
commit 5db0c4fa95
2 files changed
+165 -85
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EvenPerfectBitScanner/Program.cs
+10
View File
@@ -103,6 +103,7 @@ internal static class Program
bool useResidue = false; // M_p test via residue divisors (replaces LL/incremental)
bool useDivisor = false; // M_p divisibility by specific divisor
bool useByDivisor = false; // Iterative divisor scan across primes
bool useDivisorCycles = false;
UInt128 divisor = UInt128.Zero;
// Device routing
bool useGpuCycles = true;
@@ -184,6 +185,13 @@ internal static class Program
{
divisor = UInt128.Parse(arg.AsSpan(arg.IndexOf('=') + 1));
}
else if (arg.StartsWith("--use-divisor-cycles=", StringComparison.OrdinalIgnoreCase))
{
if (bool.TryParse(arg.AsSpan(arg.IndexOf('=') + 1), out bool parsedBool))
{
useDivisorCycles = parsedBool;
}
}
else if (arg.StartsWith("--divisor-cycles-limit=", StringComparison.OrdinalIgnoreCase))
{
if (ulong.TryParse(arg.AsSpan(arg.IndexOf('=') + 1), out parsedLimit))
@@ -501,6 +509,7 @@ internal static class Program
_byDivisorTester = new MersenneNumberDivisorByDivisorGpuTester
{
GpuBatchSize = scanBatchSize,
UseDivisorCycles = useDivisorCycles,
};
}
@@ -1277,6 +1286,7 @@ internal static class Program
Console.WriteLine(" --divisor-cycles-batch-size=<value> batch size for cycles generation (default 512)");
Console.WriteLine(" --divisor-cycles-continue continue divisor cycles generation");
Console.WriteLine(" --divisor-cycles-limit=<value> cycle search iterations when --mersenne=divisor");
Console.WriteLine(" --use-divisor-cycles=true|false enable divisor cycle filtering in --mersenne=bydivisor (default false)");
Console.WriteLine(" --use-order test primality via q order");
Console.WriteLine(" --workaround-mod avoid '%' operator on the GPU");
PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs
+155 -85
View File
@@ -6,6 +6,7 @@ using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using ILGPU;
using ILGPU.Runtime;
using PerfectNumbers.Core;
namespace PerfectNumbers.Core.Gpu;
@@ -16,6 +17,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
private ulong _divisorLimit;
private bool _isConfigured;
private ulong _lastStatusDivisor;
private bool _useDivisorCycles;
public readonly struct MontgomeryDivisorData
{
@@ -47,6 +49,12 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
set => _gpuBatchSize = Math.Max(1, value);
}
public bool UseDivisorCycles
{
get => _useDivisorCycles;
set => _useDivisorCycles = value;
}
public void ConfigureFromMaxPrime(ulong maxPrime)
{
lock (_sync)
@@ -91,12 +99,12 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
}
}
private bool CheckDivisors(ulong prime, ulong allowedMax, out ulong lastProcessed, out bool coveredRange)
{
allowedMax = Math.Min(allowedMax, _divisorLimit);
lastProcessed = 0UL;
private bool CheckDivisors(ulong prime, ulong allowedMax, out ulong lastProcessed, out bool coveredRange)
{
allowedMax = Math.Min(allowedMax, _divisorLimit);
lastProcessed = 0UL;
if (allowedMax < 3UL)
if (allowedMax < 3UL)
{
coveredRange = true;
return false;
@@ -118,40 +126,56 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
bool processedAll = false;
ulong divisor = 3UL;
try
{
while (divisor <= allowedMax)
{
int batchSize = 0;
bool reachedEndInBatch = false;
try
{
bool useCycles = _useDivisorCycles;
MersenneDivisorCycles? divisorCycles = useCycles ? MersenneDivisorCycles.Shared : null;
while (divisor <= allowedMax)
{
int batchSize = 0;
bool reachedEndInBatch = false;
while (batchSize < batchCapacity && divisor <= allowedMax)
{
ulong current = divisor;
divisors[batchSize++] = current;
while (batchSize < batchCapacity && divisor <= allowedMax)
{
ulong current = divisor;
ulong next = current + 2UL;
bool include = true;
if (useCycles)
{
ulong cycle = divisorCycles!.GetCycle(current);
if (cycle == 0UL || prime % cycle != 0UL)
{
include = false;
lastProcessed = current;
ReportStatus(lastProcessed);
}
}
ulong next = current + 2UL;
ReportStatus(lastProcessed);
if (next <= current)
{
reachedEndInBatch = true;
break;
}
if (include)
{
divisors[batchSize++] = current;
}
if (next > allowedMax)
{
divisor = next;
reachedEndInBatch = true;
break;
}
if (next <= current)
{
reachedEndInBatch = true;
break;
}
divisor = next;
}
if (next > allowedMax)
{
divisor = next;
reachedEndInBatch = true;
break;
}
if (batchSize == 0)
{
break;
}
divisor = next;
}
if (batchSize == 0)
{
break;
}
Span<MontgomeryDivisorData> divisorDataSpan = divisorData.AsSpan(0, batchSize);
var divisorView = divisorsBuffer.View.SubView(0, batchSize);
@@ -269,63 +293,108 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
private readonly Accelerator _accelerator;
private readonly Action<Index1D, MontgomeryDivisorData, ArrayView<ulong>, ArrayView<byte>> _kernel;
private readonly MemoryBuffer1D<ulong, Stride1D.Dense> _primesBuffer;
private readonly MemoryBuffer1D<byte, Stride1D.Dense> _hitsBuffer;
private readonly ulong[] _primesHost;
private readonly byte[] _hitsHost;
private bool _disposed;
private readonly MemoryBuffer1D<byte, Stride1D.Dense> _hitsBuffer;
private readonly ulong[] _primesHost;
private readonly byte[] _hitsHost;
private readonly int[] _indexHost;
private bool _disposed;
internal DivisorScanSession(MersenneNumberDivisorByDivisorGpuTester owner)
{
_owner = owner;
internal DivisorScanSession(MersenneNumberDivisorByDivisorGpuTester owner)
{
_owner = owner;
_lease = GpuContextPool.RentPreferred(preferCpu: false);
_accelerator = _lease.Accelerator;
_kernel = owner.GetKernelByPrime(_accelerator);
_primesBuffer = _accelerator.Allocate1D<ulong>(owner._gpuBatchSize);
_hitsBuffer = _accelerator.Allocate1D<byte>(owner._gpuBatchSize);
_primesHost = ArrayPool<ulong>.Shared.Rent(owner._gpuBatchSize);
_hitsHost = ArrayPool<byte>.Shared.Rent(owner._gpuBatchSize);
}
_primesBuffer = _accelerator.Allocate1D<ulong>(owner._gpuBatchSize);
_hitsBuffer = _accelerator.Allocate1D<byte>(owner._gpuBatchSize);
_primesHost = ArrayPool<ulong>.Shared.Rent(owner._gpuBatchSize);
_hitsHost = ArrayPool<byte>.Shared.Rent(owner._gpuBatchSize);
_indexHost = ArrayPool<int>.Shared.Rent(owner._gpuBatchSize);
}
public void CheckDivisor(ulong divisor, ReadOnlySpan<ulong> primes, Span<byte> hits)
{
if (_disposed)
{
throw new ObjectDisposedException(nameof(DivisorScanSession));
}
public void CheckDivisor(ulong divisor, ReadOnlySpan<ulong> primes, Span<byte> hits)
{
if (_disposed)
{
throw new ObjectDisposedException(nameof(DivisorScanSession));
}
if (primes.Length == 0)
{
return;
}
if (primes.Length == 0)
{
return;
}
int offset = 0;
int consoleStatus = 0;
int offset = 0;
int consoleStatus = 0;
bool useCycles = _owner._useDivisorCycles;
MersenneDivisorCycles? divisorCycles = useCycles ? MersenneDivisorCycles.Shared : null;
ulong cycle = useCycles ? divisorCycles!.GetCycle(divisor) : 0UL;
MontgomeryDivisorData divisorData = CreateMontgomeryDivisorData(divisor);
while (offset < primes.Length)
{
int batchSize = Math.Min(_owner._gpuBatchSize, primes.Length - offset);
Span<ulong> primeSpan = _primesHost.AsSpan(0, batchSize);
primes.Slice(offset, batchSize).CopyTo(primeSpan);
int batchSize = Math.Min(_owner._gpuBatchSize, primes.Length - offset);
Span<ulong> primeSpan = _primesHost.AsSpan(0, batchSize);
primes.Slice(offset, batchSize).CopyTo(primeSpan);
if (++consoleStatus == PerfectNumberConstants.ConsoleInterval)
{
Console.WriteLine($"...processed by-divisor candidate = {primes[0]}");
consoleStatus = 0;
}
if (++consoleStatus == PerfectNumberConstants.ConsoleInterval)
{
Console.WriteLine($"...processed by-divisor candidate = {primes[0]}");
consoleStatus = 0;
}
var primesView = _primesBuffer.View.SubView(0, batchSize);
var hitsView = _hitsBuffer.View.SubView(0, batchSize);
Span<int> indexSpan = _indexHost.AsSpan(0, batchSize);
Span<byte> hitSpan = _hitsHost.AsSpan(0, batchSize);
Span<byte> hitsSlice = hits.Slice(offset, batchSize);
int gpuCount = 0;
primesView.CopyFromCPU(ref MemoryMarshal.GetReference(primeSpan), batchSize);
_kernel(batchSize, divisorData, primesView, hitsView);
_accelerator.Synchronize();
if (useCycles)
{
for (int i = 0; i < batchSize; i++)
{
ulong primeValue = primeSpan[i];
if (cycle == 0UL || primeValue % cycle != 0UL)
{
hitsSlice[i] = 0;
continue;
}
Span<byte> hitSpan = _hitsHost.AsSpan(0, batchSize);
hitsView.CopyToCPU(ref MemoryMarshal.GetReference(hitSpan), batchSize);
hitSpan.CopyTo(hits.Slice(offset, batchSize));
offset += batchSize;
}
}
indexSpan[gpuCount] = i;
primeSpan[gpuCount] = primeValue;
gpuCount++;
}
if (gpuCount > 0)
{
var primesView = _primesBuffer.View.SubView(0, gpuCount);
var hitsView = _hitsBuffer.View.SubView(0, gpuCount);
primesView.CopyFromCPU(ref MemoryMarshal.GetReference(primeSpan.Slice(0, gpuCount)), gpuCount);
_kernel(gpuCount, divisorData, primesView, hitsView);
_accelerator.Synchronize();
hitsView.CopyToCPU(ref MemoryMarshal.GetReference(hitSpan.Slice(0, gpuCount)), gpuCount);
for (int i = 0; i < gpuCount; i++)
{
hitsSlice[indexSpan[i]] = hitSpan[i];
}
}
}
else
{
var primesView = _primesBuffer.View.SubView(0, batchSize);
var hitsView = _hitsBuffer.View.SubView(0, batchSize);
primesView.CopyFromCPU(ref MemoryMarshal.GetReference(primeSpan), batchSize);
_kernel(batchSize, divisorData, primesView, hitsView);
_accelerator.Synchronize();
hitsView.CopyToCPU(ref MemoryMarshal.GetReference(hitSpan), batchSize);
hitSpan.CopyTo(hitsSlice);
}
offset += batchSize;
}
}
public void Dispose()
{
@@ -334,14 +403,15 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
return;
}
_disposed = true;
ArrayPool<ulong>.Shared.Return(_primesHost, clearArray: true);
ArrayPool<byte>.Shared.Return(_hitsHost, clearArray: true);
_primesBuffer.Dispose();
_hitsBuffer.Dispose();
_lease.Dispose();
}
}
_disposed = true;
ArrayPool<ulong>.Shared.Return(_primesHost, clearArray: true);
ArrayPool<byte>.Shared.Return(_hitsHost, clearArray: true);
ArrayPool<int>.Shared.Return(_indexHost, clearArray: true);
_primesBuffer.Dispose();
_hitsBuffer.Dispose();
_lease.Dispose();
}
}
private static ulong Pow2Mod(ulong exponent, MontgomeryDivisorData divisor)
{