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Merge pull request #72 from mlemanczyk/codex/implement-todos-in-mersennenumberdivisorbydivisorgputester

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Fix residue tester filters and arithmetic utilities
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Marek Lemańczyk authored and GitHub committed 2025-09-24 03:06:02 +02:00
2 parents 2484d506d6 615ae29fd6
commit d472d48a84
4 files changed
+176 -78
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PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs
+154 -63
View File
@@ -26,6 +26,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ulong, ArrayView<MontgomeryDivisorData>, ArrayView<byte>>> _kernelCache = new();
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, MontgomeryDivisorData, ArrayView<ulong>, ArrayView<byte>>> _kernelByPrimeCache = new();
private readonly ConcurrentBag<DivisorScanSession> _sessionPool = new();
private Action<Index1D, ulong, ArrayView<MontgomeryDivisorData>, ArrayView<byte>> GetKernel(Accelerator accelerator) =>
_kernelCache.GetOrAdd(accelerator, acc => acc.LoadAutoGroupedStreamKernel<Index1D, ulong, ArrayView<MontgomeryDivisorData>, ArrayView<byte>>(CheckKernel));
@@ -55,29 +56,77 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
}
public bool IsPrime(ulong prime, out bool divisorsExhausted)
{
ulong allowedMax;
bool useCycles;
int batchCapacity;
lock (_sync)
{
if (!_isConfigured)
{
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
}
ulong allowedMax = ComputeAllowedMaxDivisor(prime);
allowedMax = ComputeAllowedMaxDivisor(prime, _divisorLimit);
useCycles = _useDivisorCycles;
batchCapacity = _gpuBatchSize;
}
if (allowedMax < 3UL)
{
divisorsExhausted = true;
return true;
}
bool composite, coveredRange;
bool composite;
bool coveredRange;
ulong processedCount;
ulong lastProcessed;
// TODO: Let's rework this to check if the number is prime and check divisors outside of the lock. Lock and update the state afterwards.
var gpuLease = GpuContextPool.RentPreferred(preferCpu: false);
var accelerator = gpuLease.Accelerator;
var kernel = GetKernel(accelerator);
var divisorsBuffer = accelerator.Allocate1D<MontgomeryDivisorData>(batchCapacity);
var hitsBuffer = accelerator.Allocate1D<byte>(batchCapacity);
ulong[] divisors = ArrayPool<ulong>.Shared.Rent(batchCapacity);
byte[] hits = ArrayPool<byte>.Shared.Rent(batchCapacity);
MontgomeryDivisorData[] divisorData = ArrayPool<MontgomeryDivisorData>.Shared.Rent(batchCapacity);
try
{
composite = CheckDivisors(
prime,
allowedMax,
useCycles,
accelerator,
kernel,
divisorsBuffer,
hitsBuffer,
divisors,
hits,
divisorData,
out lastProcessed,
out coveredRange,
out processedCount
);
}
finally
{
ArrayPool<byte>.Shared.Return(hits, clearArray: true);
ArrayPool<ulong>.Shared.Return(divisors, clearArray: true);
ArrayPool<MontgomeryDivisorData>.Shared.Return(divisorData, clearArray: true);
hitsBuffer.Dispose();
divisorsBuffer.Dispose();
gpuLease.Dispose();
}
if (processedCount > 0UL)
{
lock (_sync)
{
composite = CheckDivisors(prime, allowedMax, out ulong lastProcessed, out coveredRange);
if (lastProcessed != 0UL)
{
ReportStatus(lastProcessed);
UpdateStatusUnsafe(lastProcessed, processedCount);
}
}
@@ -91,11 +140,23 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
return true;
}
private bool CheckDivisors(ulong prime, ulong allowedMax, out ulong lastProcessed, out bool coveredRange)
private bool CheckDivisors(
ulong prime,
ulong allowedMax,
bool useCycles,
Accelerator accelerator,
Action<Index1D, ulong, ArrayView<MontgomeryDivisorData>, ArrayView<byte>> kernel,
MemoryBuffer1D<MontgomeryDivisorData, Stride1D.Dense> divisorsBuffer,
MemoryBuffer1D<byte, Stride1D.Dense> hitsBuffer,
ulong[] divisors,
byte[] hits,
MontgomeryDivisorData[] divisorData,
out ulong lastProcessed,
out bool coveredRange,
out ulong processedCount)
{
// TODO: We should be able to calculate allowedMax outside in the parent method, unless it depends from some changing value.
allowedMax = Math.Min(allowedMax, _divisorLimit);
lastProcessed = 0UL;
processedCount = 0UL;
if (allowedMax < 3UL)
{
@@ -103,24 +164,13 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
return false;
}
// TODO: Rent these in the parent method before the loops - batch size doesn't change
var gpuLease = GpuContextPool.RentPreferred(preferCpu: false);
var accelerator = gpuLease.Accelerator;
var kernel = GetKernel(accelerator);
int batchCapacity = _gpuBatchSize;
// TODO: Rent buffers in the parent method before the loops - batch size doesn't change
var divisorsBuffer = accelerator.Allocate1D<MontgomeryDivisorData>(batchCapacity);
var hitsBuffer = accelerator.Allocate1D<byte>(batchCapacity);
ulong[] divisors = ArrayPool<ulong>.Shared.Rent(batchCapacity);
byte[] hits = ArrayPool<byte>.Shared.Rent(batchCapacity);
MontgomeryDivisorData[] divisorData = ArrayPool<MontgomeryDivisorData>.Shared.Rent(batchCapacity);
int batchCapacity = (int)divisorsBuffer.Length;
bool composite = false;
bool processedAll = false;
ulong cycle, divisor = 3UL, next;
int batchSize, i;
bool reachedEndInBatch, useCycles = _useDivisorCycles;
bool reachedEndInBatch;
Span<MontgomeryDivisorData> divisorDataSpan;
Span<ulong> divisorSpan;
@@ -136,24 +186,38 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
while (batchSize < batchCapacity && divisor <= allowedMax)
{
ulong currentDivisor = divisor;
ulong nextDivisor = currentDivisor + 2UL;
processedCount++;
if (useCycles)
{
cycle = divisorCycles!.GetCycle(divisor);
cycle = divisorCycles!.GetCycle(currentDivisor);
if (cycle == 0UL || prime % cycle != 0UL)
{
ReportStatus(divisor);
}
else
lastProcessed = currentDivisor;
if (nextDivisor <= currentDivisor)
{
divisors[batchSize++] = divisor;
}
}
else
{
divisors[batchSize++] = divisor;
reachedEndInBatch = true;
break;
}
next = divisor + 2UL;
if (nextDivisor > allowedMax)
{
divisor = nextDivisor;
reachedEndInBatch = true;
break;
}
divisor = nextDivisor;
continue;
}
}
divisors[batchSize++] = currentDivisor;
lastProcessed = currentDivisor;
next = nextDivisor;
// This will be only true when we exceed ulong.MaxValue
if (next <= divisor)
@@ -174,6 +238,11 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
if (batchSize == 0)
{
if (reachedEndInBatch)
{
processedAll = true;
}
break;
}
@@ -199,11 +268,15 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
if (hitsSpan[i] != 0)
{
composite = true;
lastProcessed = divisorSpan[i];
break;
}
}
ReportStatus(divisorSpan[i < batchSize ? i : i - 1]);
if (!composite)
{
lastProcessed = divisorSpan[batchSize - 1];
}
if (composite)
{
break;
@@ -218,25 +291,9 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
coveredRange = composite || processedAll || divisor > allowedMax;
ArrayPool<byte>.Shared.Return(hits, clearArray: true);
ArrayPool<ulong>.Shared.Return(divisors, clearArray: true);
ArrayPool<MontgomeryDivisorData>.Shared.Return(divisorData, clearArray: true);
hitsBuffer.Dispose();
divisorsBuffer.Dispose();
gpuLease.Dispose();
return composite;
}
private void ReportStatus(ulong divisor)
{
if (++_lastStatusDivisor == PerfectNumberConstants.ConsoleInterval)
{
Console.WriteLine($"...processed by-divisor candidate = {divisor}");
_lastStatusDivisor = 0;
}
}
private static ulong ComputeDivisorLimitFromMaxPrime(ulong maxPrime)
{
if (maxPrime <= 1UL)
@@ -252,7 +309,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
return (1UL << (int)(maxPrime - 1UL)) - 1UL;
}
private ulong ComputeAllowedMaxDivisor(ulong prime)
private static ulong ComputeAllowedMaxDivisor(ulong prime, ulong divisorLimit)
{
if (prime <= 1UL)
{
@@ -261,10 +318,34 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
if (prime - 1UL >= 64UL)
{
return _divisorLimit;
return divisorLimit;
}
return Math.Min((1UL << (int)(prime - 1UL)) - 1UL, _divisorLimit);
return Math.Min((1UL << (int)(prime - 1UL)) - 1UL, divisorLimit);
}
private void UpdateStatusUnsafe(ulong lastProcessed, ulong processedCount)
{
if (processedCount == 0UL)
{
return;
}
ulong interval = (ulong)PerfectNumberConstants.ConsoleInterval;
if (interval == 0UL)
{
_lastStatusDivisor = 0UL;
return;
}
ulong total = _lastStatusDivisor + processedCount;
ulong messages = total / interval;
_lastStatusDivisor = total % interval;
for (ulong i = 0; i < messages; i++)
{
Console.WriteLine($"...processed by-divisor candidate = {lastProcessed}");
}
}
private static void CheckKernel(Index1D index, ulong prime, ArrayView<MontgomeryDivisorData> divisors, ArrayView<byte> hits)
@@ -280,7 +361,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
hits[index] = Pow2Mod(prime, divisor) == 1UL ? (byte)1 : (byte)0;
}
// TODO: Let's create a pool for these and let's rent them and return, when not needed
public sealed class DivisorScanSession : IDisposable
{
private readonly MersenneNumberDivisorByDivisorGpuTester _owner;
@@ -307,6 +387,11 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
_indexHost = ArrayPool<int>.Shared.Rent(owner._gpuBatchSize);
}
internal void Reset()
{
_disposed = false;
}
public void CheckDivisor(ulong divisor, ReadOnlySpan<ulong> primes, Span<byte> hits)
{
if (_disposed)
@@ -411,15 +496,15 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
}
_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();
_owner.ReturnSession(this);
}
}
internal void ReturnSession(DivisorScanSession session)
{
_sessionPool.Add(session);
}
private static ulong Pow2Mod(ulong exponent, in MontgomeryDivisorData divisor)
{
ulong modulus = divisor.Modulus;
@@ -544,7 +629,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
}
return ComputeAllowedMaxDivisor(prime);
return ComputeAllowedMaxDivisor(prime, _divisorLimit);
}
}
@@ -557,6 +642,12 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
}
if (_sessionPool.TryTake(out DivisorScanSession? session))
{
session.Reset();
return session;
}
return new DivisorScanSession(this);
}
}
PerfectNumbers.Core/Gpu/MersenneNumberResidueGpuTester.cs
+6 -7
View File
@@ -22,12 +22,11 @@ public class MersenneNumberResidueGpuTester(bool useGpuOrder)
ResiduePrimeViews primeViews = GpuKernelPool.EnsureSmallPrimesOnDevice(accelerator);
int batchSize = GpuConstants.ScanBatchSize;
UInt128 kStart = 1UL;
UInt128 limit = maxK + UInt128.One;
byte last = lastIsSeven ? (byte)1 : (byte)0;
var kernel = gpuLease.Pow2ModKernel;
ulong step3 = exponent % 3UL,
step5 = exponent % 5UL,
step8 = exponent % 8UL,
step10 = exponent.Mod10();
twoP.Mod10_8_5_3(out ulong step10, out ulong step8, out ulong step5, out ulong step3);
step10 = step10.Mod10();
GpuUInt128 twoPGpu = (GpuUInt128)twoP;
@@ -46,9 +45,9 @@ public class MersenneNumberResidueGpuTester(bool useGpuOrder)
try
{
while (kStart < maxK && Volatile.Read(ref isPrime))
while (kStart < limit && Volatile.Read(ref isPrime))
{
UInt128 remaining = maxK - kStart;
UInt128 remaining = limit - kStart;
int currentSize = remaining > batchSize128 ? batchSize : (int)remaining;
Span<ulong> orders = orderArray.AsSpan(0, currentSize);
ref ulong ordersRef = ref MemoryMarshal.GetReference(orders);
@@ -84,7 +83,7 @@ public class MersenneNumberResidueGpuTester(bool useGpuOrder)
UInt128 processed = (UInt128)currentSize;
kStart += processed;
if (kStart < maxK)
if (kStart < limit)
{
if (processed == batchSize128)
{
PerfectNumbers.Core/UInt128Extensions.cs
+11 -4
View File
@@ -148,10 +148,16 @@ public static class UInt128Extensions
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod7(this UInt128 value)
{
ulong remainder = (((ulong)value) % 7UL) + (((ulong)(value >> 64)) % 7UL) << 1;
while (remainder >= 7UL)
ulong low = (ulong)value % 7UL;
ulong high = (ulong)(value >> 64) % 7UL;
ulong remainder = low + (high * 2UL);
if (remainder >= 7UL)
{
remainder -= 7UL;
if (remainder >= 7UL)
{
remainder -= 7UL;
}
}
return remainder;
@@ -164,8 +170,9 @@ public static class UInt128Extensions
public static ulong Mod10(this UInt128 value128)
{
// Split and fold under mod 10: 2^64 ≡ 6 (mod 10)
ulong value = (ulong)value128;
return ((value % 10UL) + ((value >> 64) % 10UL) * 6UL) % 10UL;
ulong low = (ulong)value128;
ulong high = (ulong)(value128 >> 64);
return ((low % 10UL) + ((high % 10UL) * 6UL)) % 10UL;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
PerfectNumbers.Core/ULongExtensions.cs
+5 -4
View File
@@ -48,13 +48,14 @@ public static class ULongExtensions
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong FastDiv64(this ulong value, ulong divisor, ulong mul)
{
mul = value.MulHigh(mul);
if ((UInt128)value - mul.Mul64(divisor) >= divisor)
ulong quotient = (ulong)(((UInt128)value * mul) >> 64);
UInt128 remainder = (UInt128)value - ((UInt128)quotient * divisor);
if (remainder >= divisor)
{
mul++;
quotient++;
}
return mul;
return quotient;
}
public const ulong WordBitMask = 0xFFFFUL;