--mersenne=bydivisor testers and sessions integrated and converted to structs.

This commit is contained in:
mlemanczyk committed 2025-12-18 05:07:31 +01:00
1 parent 3c80221105
commit 2abc6aae49
32 files changed
+3814 -1505

No files matched your search

+111
View File
@@ -0,0 +1,111 @@
using System.Runtime.CompilerServices;
namespace PerfectNumbers.Core.Cpu;
public static class ByteExtensions
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod3(this byte value, byte delta)
{
const int Modulus = 3;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod7(this byte value, byte delta)
{
const int Modulus = 7;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod13(this byte value, byte delta)
{
const int Modulus = 13;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod17(this byte value, byte delta)
{
const int Modulus = 17;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod19(this byte value, byte delta)
{
const int Modulus = 19;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod10(this byte value, byte delta)
{
const int Modulus = 10;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod11(this byte value, byte delta)
{
const int Modulus = 11;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte AddMod8(this byte value, byte delta)
{
return (byte)((value + delta) & 7);
}
}
@@ -0,0 +1,10 @@
using PerfectNumbers.Core.Gpu;
namespace PerfectNumbers.Core.Cpu;
internal struct GpuUInt128WorkSet
{
public GpuUInt128 Step;
public GpuUInt128 Divisor;
public GpuUInt128 Limit;
}
@@ -3,23 +3,31 @@ using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
internal sealed class MersenneCpuDivisorScanSession(PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice) : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
{
private Func<ulong, MontgomeryDivisorData, ulong> _getCycleLength = orderDevice switch
internal struct MersenneCpuDivisorScanSessionWithCpuOrder() : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
{
ComputationDevice.Gpu => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor, divisorData),
ComputationDevice.Hybrid => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor, divisorData),
_ => static (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor, divisorData),
};
private readonly CycleRemainderStepper _cycleStepper = new();
private ExponentRemainderStepperCpu? _exponentStepper;
public void Configure(PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice)
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public readonly void Configure()
{
_getCycleLength = orderDevice switch
}
private static ulong _hits;
private static ulong _misses;
private static void PrintStats(bool wasHit)
{
if (wasHit)
{
ComputationDevice.Gpu => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor, divisorData),
ComputationDevice.Hybrid => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor, divisorData),
_ => static (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor, divisorData),
};
Interlocked.Increment(ref _hits);
}
else
{
Interlocked.Increment(ref _misses);
}
Console.WriteLine($"MersenneCpuDivisorScanSession, ExponentStepper hits: $_hits, misses: $_misses");
}
public bool CheckDivisor(
@@ -45,7 +53,154 @@ internal sealed class MersenneCpuDivisorScanSession(PrimeOrderCalculatorAccelera
if (divisorCycle == 0UL)
{
divisorCycle = _getCycleLength(divisor, divisorData);
divisorCycle = DivisorCycleCache.Shared.GetCycleLengthCpu(divisor, divisorData);
// This never kicks off in production code
// if (divisorCycle == 0UL)
// {
// // DivisorCycleCache guarantees a positive cycle for divisors greater than one.
// throw new InvalidOperationException($"Divisor cycle solver returned zero for divisor {divisor}.");
// }
}
// Keep these remainder steppers in place so future updates continue reusing the previously computed residues.
// They are critical for avoiding repeated full Montgomery exponentiation work when scanning divisors.
CycleRemainderStepper cycleStepper = _cycleStepper;
cycleStepper.CycleLength = divisorCycle;
if (cycleStepper.Initialize(primes[0]) == 0UL)
{
return true;
}
if (_exponentStepper is not { } exponentStepper)
{
_exponentStepper = exponentStepper = new(divisorData, divisorCycle);
}
else
{
if (!exponentStepper.MatchesDivisor(divisorData, divisorCycle))
{
_exponentStepper = exponentStepper = new(divisorData, divisorCycle);
}
}
if (exponentStepper.InitializeCpuIsUnity(primes[0]))
{
return true;
}
for (int i = 1; i < length; i++)
{
if (cycleStepper.ComputeNext(primes[i]) != 0UL)
{
continue;
}
if (exponentStepper.ComputeNextIsUnity(primes[i]))
{
return true;
}
}
return false;
}
// [MethodImpl(MethodImplOptions.AggressiveInlining)]
// public void Return() => ThreadStaticPools.ReturnMersenneCpuDivisorSession(this);
}
internal struct MersenneCpuDivisorScanSessionWithHybridOrder() : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
{
private PrimeOrderCalculatorAccelerator? _gpu;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void Configure(PrimeOrderCalculatorAccelerator gpu)
{
_gpu = gpu;
}
public bool CheckDivisor(
ulong divisor,
in MontgomeryDivisorData divisorData,
ulong divisorCycle,
in ReadOnlySpan<ulong> primes)
{
int length = primes.Length;
var gpu = _gpu ?? throw new InvalidOperationException("Session was not configured with an accelerator.");
if (divisorCycle == 0UL)
{
divisorCycle = DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor, divisorData);
}
// Keep these remainder steppers in place so future updates continue reusing the previously computed residues.
// They are critical for avoiding repeated full Montgomery exponentiation work when scanning divisors.
var cycleStepper = new CycleRemainderStepper(divisorCycle);
if (cycleStepper.Initialize(primes[0]) == 0UL)
{
return true;
}
var exponentStepper = new ExponentRemainderStepperCpu(divisorData, divisorCycle);
if (exponentStepper.InitializeCpuIsUnity(primes[0]))
{
return true;
}
for (int i = 1; i < length; i++)
{
if (cycleStepper.ComputeNext(primes[i]) != 0UL)
{
continue;
}
if (exponentStepper.ComputeNextIsUnity(primes[i]))
{
return true;
}
}
return false;
}
// [MethodImpl(MethodImplOptions.AggressiveInlining)]
// public void Return() => ThreadStaticPools.ReturnMersenneCpuDivisorSession(this);
}
internal struct MersenneCpuDivisorScanSessionWithGpuOrder() : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
{
private PrimeOrderCalculatorAccelerator? _gpu;
public void Configure(PrimeOrderCalculatorAccelerator gpu)
{
_gpu = gpu;
}
public bool CheckDivisor(
ulong divisor,
in MontgomeryDivisorData divisorData,
ulong divisorCycle,
in ReadOnlySpan<ulong> primes)
{
int length = primes.Length;
var gpu = _gpu ?? throw new InvalidOperationException("Session was not configured with an accelerator.");
// EvenPerfectBitScanner always provides at least one exponent on this path.
// Keep the guard commented out for tests that might reuse the session differently.
// if (length == 0)
// {
// return false;
// }
// This never kicks off in production code
// if (divisorData.Modulus != divisor)
// {
// throw new InvalidOperationException("Divisor data is for a different modulus");
// // cachedData = MontgomeryDivisorData.FromModulus(divisor);
// }
if (divisorCycle == 0UL)
{
divisorCycle = DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor, divisorData);
// This never kicks off in production code
// if (divisorCycle == 0UL)
// {
@@ -84,6 +239,6 @@ internal sealed class MersenneCpuDivisorScanSession(PrimeOrderCalculatorAccelera
return false;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Return() => ThreadStaticPools.ReturnMersenneCpuDivisorSession(this);
// [MethodImpl(MethodImplOptions.AggressiveInlining)]
// public void Return() => ThreadStaticPools.ReturnMersenneCpuDivisorSession(this);
}
@@ -1,980 +0,0 @@
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Globalization;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
public sealed class MersenneNumberDivisorByDivisorCpuTester(ComputationDevice orderDevice = ComputationDevice.Hybrid) : IMersenneNumberDivisorByDivisorTester
{
private BigInteger _divisorLimit;
private int _batchSize = 1_024;
private BigInteger _minK = BigInteger.One;
private readonly ComputationDevice OrderDevice = orderDevice;
private readonly TryCycleLengthDelegate _tryCalculateCycleLengthForExponent = orderDevice switch
{
ComputationDevice.Gpu => TryCalculateCycleLengthForExponentGpu,
ComputationDevice.Hybrid => TryCalculateCycleLengthForExponentHybrid,
_ => TryCalculateCycleLengthForExponentCpu,
};
private readonly CalculateCycleLengthDelegate _calculateCycleLength = orderDevice switch
{
ComputationDevice.Gpu => CalculateCycleLengthGpu,
ComputationDevice.Hybrid => CalculateCycleLengthHybrid,
_ => CalculateCycleLengthCpu,
};
private string? _stateFilePath;
private int _stateCounter;
private BigInteger _lastSavedK;
private delegate bool TryCycleLengthDelegate(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
ulong exponent,
in MontgomeryDivisorData divisorData,
out ulong cycleLength,
out bool primeOrderFailed);
private delegate ulong CalculateCycleLengthDelegate(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
in MontgomeryDivisorData divisorData,
bool skipPrimeOrderHeuristic);
[ThreadStatic]
private static GpuUInt128WorkSet _divisorScanGpuWorkSet;
private struct GpuUInt128WorkSet
{
public GpuUInt128 Step;
public GpuUInt128 Divisor;
public GpuUInt128 Limit;
}
public int BatchSize
{
get => _batchSize;
set => _batchSize = Math.Max(1, value);
}
public BigInteger MinK
{
get => _minK;
set => _minK = value < BigInteger.One ? BigInteger.One : value;
}
public string? StateFilePath
{
get => _stateFilePath;
set => _stateFilePath = value;
}
public void ResetStateTracking()
{
_stateCounter = 0;
}
public void ResumeFromState(BigInteger lastSavedK)
{
_lastSavedK = lastSavedK;
_minK = lastSavedK + BigInteger.One;
_stateCounter = 0;
}
public void ConfigureFromMaxPrime(ulong maxPrime)
{
_divisorLimit = ComputeDivisorLimitFromMaxPrimeBig(maxPrime);
}
public ulong DivisorLimit
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get
{
if (_divisorLimit.IsZero)
{
return ulong.MaxValue;
}
return _divisorLimit > ulong.MaxValue ? ulong.MaxValue : (ulong)_divisorLimit;
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ulong GetAllowedMaxDivisor(ulong prime) => ComputeAllowedMaxDivisor(prime, _divisorLimit);
public bool IsPrime(PrimeOrderCalculatorAccelerator gpu, ulong prime, out bool divisorsExhausted, out BigInteger divisor)
{
BigInteger allowedMax = ComputeAllowedMaxDivisorBig(prime, _divisorLimit);
// The CPU by-divisor run always hands us primes with enormous divisor limits, so the fallback below never executes.
// if (allowedMax < 3UL)
// {
// // EvenPerfectBitScanner routes primes below the small-divisor cutoff to the GPU path, so the CPU path still sees
// // trivial candidates during targeted tests. Short-circuit here to keep those runs aligned with the production flow.
// divisorsExhausted = true;
// return true;
// }
bool composite = CheckDivisors(
gpu,
prime,
allowedMax,
_minK,
out bool processedAll,
out divisor);
if (composite)
{
divisorsExhausted = true;
return false;
}
divisorsExhausted = processedAll || composite;
divisor = BigInteger.Zero;
return true;
}
public void PrepareCandidates(in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
{
ulong divisorLimit = GetAllowedDivisorLimitForSpan(_divisorLimit);
int length = primes.Length;
for (int index = 0; index < length; index++)
{
allowedMaxValues[index] = ComputeAllowedMaxDivisor(primes[index], divisorLimit);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu) => ThreadStaticPools.RentMersenneCpuDivisorSession(gpu, OrderDevice);
private bool CheckDivisors(
PrimeOrderCalculatorAccelerator gpu,
ulong prime,
BigInteger allowedMax,
BigInteger minK,
out bool processedAll,
out BigInteger foundDivisor)
{
BigInteger normalizedMinK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger step = ((BigInteger)prime) << 1;
BigInteger firstDivisor = (step * normalizedMinK) + BigInteger.One;
bool unlimited = allowedMax.IsZero;
bool fits64 = normalizedMinK <= ulong.MaxValue && firstDivisor <= ulong.MaxValue;
bool limitFits64 = unlimited || allowedMax <= ulong.MaxValue;
if (fits64 && limitFits64)
{
ulong allowedMax64 = unlimited ? ulong.MaxValue : (ulong)allowedMax;
bool composite64 = CheckDivisors64Bit(
gpu,
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
foundDivisor = foundDivisor64;
return composite64;
}
if (fits64 && allowedMax > ulong.MaxValue)
{
ulong allowedMax64 = ulong.MaxValue;
bool composite64 = CheckDivisors64Bit(
gpu,
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
if (composite64)
{
foundDivisor = foundDivisor64;
return true;
}
BigInteger iterations = ((BigInteger)(allowedMax64 - (ulong)firstDivisor) / (ulong)step) + BigInteger.One;
BigInteger nextK = normalizedMinK + iterations;
return CheckDivisorsLarge(
gpu,
prime,
allowedMax,
nextK,
step,
out processedAll,
out foundDivisor);
}
return CheckDivisorsLarge(
gpu,
prime,
allowedMax,
normalizedMinK,
step,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64Bit(
PrimeOrderCalculatorAccelerator gpu,
ulong prime,
ulong allowedMax,
ulong minK,
out bool processedAll,
out ulong foundDivisor)
{
foundDivisor = 0UL;
processedAll = true;
ulong currentK = minK < 1UL ? 1UL : minK;
// The EvenPerfectBitScanner feeds primes >= 138,000,000 here, so allowedMax >= 3 in production runs.
// Keeping the guard commented out documents the reasoning for benchmarks and tests.
// if (allowedMax < 3UL)
// {
// return false;
// }
ref GpuUInt128WorkSet workSet = ref _divisorScanGpuWorkSet;
ref GpuUInt128 step = ref workSet.Step;
step.High = 0UL;
step.Low = prime;
step.ShiftLeft(1);
ref GpuUInt128 limit = ref workSet.Limit;
limit.High = 0UL;
limit.Low = allowedMax;
ref GpuUInt128 divisor = ref workSet.Divisor;
divisor.High = step.High;
divisor.Low = step.Low;
divisor.Add(1UL);
if (minK > 1UL)
{
GpuUInt128 offset = new(minK - 1UL);
divisor = step * offset;
divisor.Add(1UL);
}
if (divisor.CompareTo(limit) > 0)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
// Intentionally recomputes factorizations without a per-thread cache.
// The previous factor cache recorded virtually no hits and only slowed down the scan.
ulong stepHigh = step.High;
ulong stepLow = step.Low;
ulong limitHigh = limit.High;
ulong divisorLow = divisor.Low;
if (stepHigh == 0UL && limitHigh == 0UL)
{
ulong maxK = allowedMax > 0UL ? (allowedMax - 1UL) / stepLow : 0UL;
if (maxK == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong startK = minK < 1UL ? 1UL : minK;
bool processedTop = true;
bool processedBottom = true;
bool composite = false;
if (startK <= maxK)
{
composite = CheckDivisors64Range(
gpu,
prime,
stepLow,
allowedMax,
startK,
maxK,
ref currentK,
out processedTop,
out foundDivisor);
if (composite)
{
processedAll = true;
return true;
}
}
ulong lowerEnd = startK > 1UL ? startK - 1UL : 0UL;
if (lowerEnd >= 1UL && startK == 1UL)
{
lowerEnd = Math.Min(lowerEnd, maxK);
currentK = 1UL;
composite = CheckDivisors64Range(
gpu,
prime,
stepLow,
allowedMax,
1UL,
lowerEnd,
ref currentK,
out processedBottom,
out foundDivisor);
}
processedAll = processedTop && processedBottom;
return composite;
}
ulong divisorHigh = divisor.High;
var residueStepper = new MersenneDivisorResidueStepper(prime, step, divisor);
while (divisor.CompareTo(limit) <= 0)
{
if (residueStepper.IsAdmissible())
{
ulong candidate = divisor.Low;
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(candidate);
ulong divisorCycle;
// Divisors generated from 2 * k * p + 1 exceed the small-cycle snapshot when p >= 138,000,000, so the short path below never runs.
if (!_tryCalculateCycleLengthForExponent(
candidate,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
// Divisors produced by 2 * k * p + 1 always exceed PerfectNumberConstants.MaxQForDivisorCycles
// for the exponents scanned here, so skip the unused cache fallback and compute directly.
divisorCycle = _calculateCycleLength(
candidate,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
// A cycle equal to the tested exponent (which is prime in this path) guarantees that the candidate divides
// the corresponding Mersenne number because the order of 2 modulo the divisor is exactly p.
foundDivisor = candidate;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
divisor.Add(step);
currentK++;
residueStepper.Advance();
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
private bool CheckDivisorsLarge(
PrimeOrderCalculatorAccelerator gpu,
ulong prime,
BigInteger allowedMax,
BigInteger minK,
BigInteger step,
out bool processedAll,
out BigInteger foundDivisor)
{
processedAll = true;
foundDivisor = BigInteger.Zero;
BigInteger currentK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger divisor = (step * currentK) + BigInteger.One;
_ = gpu;
if (allowedMax.IsZero)
{
processedAll = false;
return false;
}
if (divisor > allowedMax)
{
return false;
}
LastDigit lastDigit = (prime & 3UL) == 3UL ? LastDigit.Seven : LastDigit.One;
ushort decimalMask = DivisorGenerator.GetDecimalMask(lastDigit);
var rem10 = new BigIntegerCycleRemainderStepper(10);
var rem8 = new BigIntegerCycleRemainderStepper(8);
var rem5 = new BigIntegerCycleRemainderStepper(5);
var rem3 = new BigIntegerCycleRemainderStepper(3);
var rem7 = new BigIntegerCycleRemainderStepper(7);
var rem11 = new BigIntegerCycleRemainderStepper(11);
var rem13 = new BigIntegerCycleRemainderStepper(13);
var rem17 = new BigIntegerCycleRemainderStepper(17);
var rem19 = new BigIntegerCycleRemainderStepper(19);
byte remainder10 = (byte)rem10.Initialize(divisor);
byte remainder8 = (byte)rem8.Initialize(divisor);
byte remainder5 = (byte)rem5.Initialize(divisor);
byte remainder3 = (byte)rem3.Initialize(divisor);
byte remainder7 = (byte)rem7.Initialize(divisor);
byte remainder11 = (byte)rem11.Initialize(divisor);
byte remainder13 = (byte)rem13.Initialize(divisor);
byte remainder17 = (byte)rem17.Initialize(divisor);
byte remainder19 = (byte)rem19.Initialize(divisor);
while (divisor <= allowedMax)
{
bool passesSmallModuli = remainder3 != 0 && remainder5 != 0 && remainder7 != 0 && remainder11 != 0 && remainder13 != 0 && remainder17 != 0 && remainder19 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
if (IsProbablePrimeBigInteger(divisor))
{
BigInteger powResult = BigInteger.ModPow(2, prime, divisor);
RecordState(currentK);
if (powResult.IsOne)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
}
else
{
RecordState(currentK);
}
}
currentK += BigInteger.One;
divisor += step;
remainder10 = (byte)rem10.ComputeNext(divisor);
remainder8 = (byte)rem8.ComputeNext(divisor);
remainder5 = (byte)rem5.ComputeNext(divisor);
remainder3 = (byte)rem3.ComputeNext(divisor);
remainder7 = (byte)rem7.ComputeNext(divisor);
remainder11 = (byte)rem11.ComputeNext(divisor);
remainder13 = (byte)rem13.ComputeNext(divisor);
remainder17 = (byte)rem17.ComputeNext(divisor);
remainder19 = (byte)rem19.ComputeNext(divisor);
if (divisor > allowedMax)
{
break;
}
}
processedAll = true;
foundDivisor = BigInteger.Zero;
return false;
}
private bool CheckDivisors64Range(
PrimeOrderCalculatorAccelerator gpu,
ulong prime,
ulong step,
ulong allowedMax,
ulong startK,
ulong endK,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
if (startK < 1UL || endK < startK)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
currentK = startK;
UInt128 step128 = step;
UInt128 allowedMax128 = allowedMax;
UInt128 startDivisor128 = (step128 * startK) + UInt128.One;
if (startDivisor128 > allowedMax128)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
UInt128 rangeLimit128 = (step128 * endK) + UInt128.One;
if (rangeLimit128 > allowedMax128)
{
rangeLimit128 = allowedMax128;
}
ulong startDivisor = (ulong)startDivisor128;
ulong rangeLimit = (ulong)rangeLimit128;
var residueStepper = new MersenneDivisorResidueStepper(prime, (GpuUInt128)step128, (GpuUInt128)startDivisor128);
return CheckDivisors64(
gpu,
prime,
step,
rangeLimit,
startDivisor,
ref residueStepper,
ref currentK,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64(
PrimeOrderCalculatorAccelerator gpu,
ulong prime,
ulong step,
ulong limit,
ulong divisor,
ref MersenneDivisorResidueStepper residueStepper,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
bool canAdvance = step <= limit;
if (!canAdvance)
{
if (divisor <= limit && residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!_tryCalculateCycleLengthForExponent(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = _calculateCycleLength(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
if (divisor > limit)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong remainingIterations = ((limit - divisor) / step) + 1UL;
while (true)
{
if (residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!_tryCalculateCycleLengthForExponent(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = _calculateCycleLength(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
remainingIterations--;
if (remainingIterations == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
divisor += step;
currentK++;
residueStepper.Advance();
}
}
private static byte CheckDivisor(ulong prime, ulong divisorCycle, in MontgomeryDivisorData divisorData)
{
ulong residue = prime.Pow2MontgomeryModWithCycleConvertToStandardCpu(divisorCycle, divisorData);
return residue == 1UL ? (byte)1 : (byte)0;
}
private void RecordState(BigInteger k)
{
string? path = _stateFilePath;
if (string.IsNullOrEmpty(path))
{
return;
}
if (k <= _lastSavedK)
{
return;
}
int next = _stateCounter + 1;
if (next >= PerfectNumberConstants.ByDivisorStateSaveInterval)
{
string? directory = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(directory))
{
Directory.CreateDirectory(directory);
}
File.AppendAllText(path, k.ToString(CultureInfo.InvariantCulture) + Environment.NewLine);
_stateCounter = 0;
_lastSavedK = k;
}
else
{
_stateCounter = next;
}
}
private static bool IsProbablePrimeBigInteger(BigInteger value)
{
if (value <= 3)
{
return value >= 2;
}
if (value.IsEven)
{
return false;
}
BigInteger d = value - 1;
int s = 0;
while ((d & 1) == 0)
{
d >>= 1;
s++;
}
ReadOnlySpan<int> bases = stackalloc int[] { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 };
for (int i = 0; i < bases.Length; i++)
{
int baseValue = bases[i];
if ((BigInteger)baseValue >= value)
{
continue;
}
var expStepper = new BigIntegerExponentStepper(value, baseValue);
BigInteger x = expStepper.Initialize(d);
if (x == 1 || x == value - 1)
{
continue;
}
bool witnessFound = true;
for (int r = 1; r < s; r++)
{
BigInteger targetExponent = d << r;
x = expStepper.ComputeNext(targetExponent);
if (x == value - 1)
{
witnessFound = false;
break;
}
}
if (witnessFound)
{
return false;
}
}
return true;
}
private static bool TryCalculateCycleLengthForExponentCpu(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
ulong exponent,
in MontgomeryDivisorData divisorData,
out ulong cycleLength,
out bool primeOrderFailed) => MersenneDivisorCycles.TryCalculateCycleLengthForExponentCpu(
divisor,
exponent,
divisorData,
out cycleLength,
out primeOrderFailed);
private static bool TryCalculateCycleLengthForExponentHybrid(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
ulong exponent,
in MontgomeryDivisorData divisorData,
out ulong cycleLength,
out bool primeOrderFailed) => MersenneDivisorCycles.TryCalculateCycleLengthForExponentHybrid(
gpu,
divisor,
exponent,
divisorData,
out cycleLength,
out primeOrderFailed);
private static bool TryCalculateCycleLengthForExponentGpu(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
ulong exponent,
in MontgomeryDivisorData divisorData,
out ulong cycleLength,
out bool primeOrderFailed) => MersenneDivisorCycles.TryCalculateCycleLengthForExponentGpu(
gpu,
divisor,
exponent,
divisorData,
out cycleLength,
out primeOrderFailed);
private static ulong CalculateCycleLengthCpu(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
in MontgomeryDivisorData divisorData,
bool skipPrimeOrderHeuristic) => MersenneDivisorCycles.CalculateCycleLengthCpu(
divisor,
divisorData,
skipPrimeOrderHeuristic);
private static ulong CalculateCycleLengthHybrid(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
in MontgomeryDivisorData divisorData,
bool skipPrimeOrderHeuristic) => MersenneDivisorCycles.CalculateCycleLengthHybrid(
gpu,
divisor,
divisorData,
skipPrimeOrderHeuristic);
private static ulong CalculateCycleLengthGpu(
ulong divisor,
PrimeOrderCalculatorAccelerator gpu,
in MontgomeryDivisorData divisorData,
bool skipPrimeOrderHeuristic) => MersenneDivisorCycles.CalculateCycleLengthGpu(
gpu,
divisor,
divisorData,
skipPrimeOrderHeuristic);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod3(byte value, byte delta)
{
const int Modulus = 3;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod7(byte value, byte delta)
{
const int Modulus = 7;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod13(byte value, byte delta)
{
const int Modulus = 13;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod17(byte value, byte delta)
{
const int Modulus = 17;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod19(byte value, byte delta)
{
const int Modulus = 19;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod10(byte value, byte delta)
{
const int Modulus = 10;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod11(byte value, byte delta)
{
const int Modulus = 11;
int sum = value + delta;
if (sum >= Modulus)
{
sum -= Modulus;
}
return (byte)sum;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static byte AddMod8(byte value, byte delta)
{
return (byte)((value + delta) & 7);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong GetAllowedDivisorLimitForSpan(BigInteger divisorLimit)
{
if (divisorLimit.IsZero)
{
return ulong.MaxValue;
}
return divisorLimit > ulong.MaxValue ? ulong.MaxValue : (ulong)divisorLimit;
}
private static BigInteger ComputeDivisorLimitFromMaxPrimeBig(ulong maxPrime)
{
if (maxPrime <= 1UL)
{
return BigInteger.Zero;
}
if (maxPrime - 1UL >= 64UL)
{
return (BigInteger.One << 256) - BigInteger.One;
}
return (BigInteger.One << (int)(maxPrime - 1UL)) - BigInteger.One;
}
private static BigInteger ComputeAllowedMaxDivisorBig(ulong prime, BigInteger divisorLimit)
{
if (prime <= 1UL)
{
return BigInteger.Zero;
}
if (divisorLimit.IsZero || prime - 1UL >= 64UL)
{
return divisorLimit;
}
BigInteger candidateLimit = (BigInteger.One << (int)(prime - 1UL)) - BigInteger.One;
if (divisorLimit.IsZero)
{
return candidateLimit;
}
return BigInteger.Min(candidateLimit, divisorLimit);
}
private static ulong ComputeAllowedMaxDivisor(ulong prime, BigInteger divisorLimit)
{
BigInteger allowed = ComputeAllowedMaxDivisorBig(prime, divisorLimit);
if (allowed.IsZero)
{
return ulong.MaxValue;
}
return allowed > ulong.MaxValue ? ulong.MaxValue : (ulong)allowed;
}
}
@@ -0,0 +1,585 @@
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Globalization;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
public struct MersenneNumberDivisorByDivisorCpuTesterWithCpuOrder() : IMersenneNumberDivisorByDivisorTester
{
public BigInteger DivisorLimit;
public BigInteger MinK = EnvironmentConfiguration.MinK;
#pragma warning disable CS8618 // StateFilePath is always set on EvenPerfectBitScanner execution path when ResumeFromState is called.
private string StateFilePath;
#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
private int _stateCounter;
private BigInteger _lastSavedK;
private GpuUInt128WorkSet _divisorScanGpuWorkSet;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResetStateTracking()
{
_stateCounter = 0;
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResumeFromState(in string stateFile, in BigInteger lastSavedK, in BigInteger minK)
{
StateFilePath = stateFile;
_lastSavedK = lastSavedK;
MinK = minK;
_stateCounter = 0;
}
public bool IsPrime(ulong prime, out bool divisorsExhausted, out BigInteger divisor)
{
BigInteger allowedMax = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisorBig(prime, DivisorLimit);
// The CPU by-divisor run always hands us primes with enormous divisor limits, so the fallback below never executes.
// if (allowedMax < 3UL)
// {
// // EvenPerfectBitScanner routes primes below the small-divisor cutoff to the GPU path, so the CPU path still sees
// // trivial candidates during targeted tests. Short-circuit here to keep those runs aligned with the production flow.
// divisorsExhausted = true;
// return true;
// }
bool composite = CheckDivisors(
prime,
allowedMax,
MinK,
out bool processedAll,
out divisor);
if (composite)
{
divisorsExhausted = true;
return false;
}
divisorsExhausted = processedAll || composite;
divisor = BigInteger.Zero;
return true;
}
public void PrepareCandidates(ulong maxPrime, in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
{
BigInteger divisorLimitBigInteger = MersenneNumberDivisorByDivisorTester.ComputeDivisorLimitFromMaxPrimeBig(maxPrime);
DivisorLimit = divisorLimitBigInteger;
ulong divisorLimit = MersenneNumberDivisorByDivisorTester.GetAllowedDivisorLimitForSpan(divisorLimitBigInteger);
int length = primes.Length;
for (int index = 0; index < length; index++)
{
allowedMaxValues[index] = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisor(primes[index], divisorLimit);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public readonly IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu) => new MersenneCpuDivisorScanSessionWithCpuOrder();
private bool CheckDivisors(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
out bool processedAll,
out BigInteger foundDivisor)
{
BigInteger normalizedMinK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger step = ((BigInteger)prime) << 1;
BigInteger firstDivisor = (step * normalizedMinK) + BigInteger.One;
bool unlimited = allowedMax.IsZero;
bool fits64 = normalizedMinK <= ulong.MaxValue && firstDivisor <= ulong.MaxValue;
bool limitFits64 = unlimited || allowedMax <= ulong.MaxValue;
if (fits64 && limitFits64)
{
ulong allowedMax64 = unlimited ? ulong.MaxValue : (ulong)allowedMax;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
foundDivisor = foundDivisor64;
return composite64;
}
if (fits64 && allowedMax > ulong.MaxValue)
{
ulong allowedMax64 = ulong.MaxValue;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
if (composite64)
{
foundDivisor = foundDivisor64;
return true;
}
BigInteger iterations = ((BigInteger)(allowedMax64 - (ulong)firstDivisor) / (ulong)step) + BigInteger.One;
BigInteger nextK = normalizedMinK + iterations;
return CheckDivisorsLarge(
prime,
allowedMax,
nextK,
step,
out processedAll,
out foundDivisor);
}
return CheckDivisorsLarge(
prime,
allowedMax,
normalizedMinK,
step,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64Bit(
ulong prime,
ulong allowedMax,
ulong minK,
out bool processedAll,
out ulong foundDivisor)
{
foundDivisor = 0UL;
ulong currentK = minK < 1UL ? 1UL : minK;
// The EvenPerfectBitScanner feeds primes >= 138,000,000 here, so allowedMax >= 3 in production runs.
// Keeping the guard commented out documents the reasoning for benchmarks and tests.
// if (allowedMax < 3UL)
// {
// return false;
// }
ref GpuUInt128WorkSet workSet = ref _divisorScanGpuWorkSet;
ref GpuUInt128 step = ref workSet.Step;
step.High = 0UL;
step.Low = prime;
step.ShiftLeft(1);
ref GpuUInt128 limit = ref workSet.Limit;
limit.High = 0UL;
limit.Low = allowedMax;
ref GpuUInt128 divisor = ref workSet.Divisor;
divisor.High = step.High;
divisor.Low = step.Low;
divisor.Add(1UL);
if (minK > 1UL)
{
GpuUInt128 offset = new(minK - 1UL);
divisor = step * offset;
divisor.Add(1UL);
}
if (divisor.CompareTo(limit) > 0)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
// Intentionally recomputes factorizations without a per-thread cache.
// The previous factor cache recorded virtually no hits and only slowed down the scan.
ulong stepHigh = step.High;
ulong stepLow = step.Low;
ulong limitHigh = limit.High;
if (stepHigh == 0UL && limitHigh == 0UL)
{
ulong maxK = allowedMax > 0UL ? (allowedMax - 1UL) / stepLow : 0UL;
if (maxK == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong startK = minK < 1UL ? 1UL : minK;
bool processedTop = true;
bool processedBottom = true;
bool composite = false;
if (startK <= maxK)
{
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
startK,
maxK,
ref currentK,
out processedTop,
out foundDivisor);
if (composite)
{
processedAll = true;
return true;
}
}
ulong lowerEnd = startK > 1UL ? startK - 1UL : 0UL;
if (lowerEnd >= 1UL && startK == 1UL)
{
lowerEnd = Math.Min(lowerEnd, maxK);
currentK = 1UL;
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
1UL,
lowerEnd,
ref currentK,
out processedBottom,
out foundDivisor);
}
processedAll = processedTop && processedBottom;
return composite;
}
var residueStepper = new MersenneDivisorResidueStepper(prime, step, divisor);
while (divisor.CompareTo(limit) <= 0)
{
if (residueStepper.IsAdmissible())
{
ulong candidate = divisor.Low;
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(candidate);
ulong divisorCycle;
// Divisors generated from 2 * k * p + 1 exceed the small-cycle snapshot when p >= 138,000,000, so the short path below never runs.
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentCpu(
candidate,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
// Divisors produced by 2 * k * p + 1 always exceed PerfectNumberConstants.MaxQForDivisorCycles
// for the exponents scanned here, so skip the unused cache fallback and compute directly.
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthCpu(
candidate,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(StateFilePath, currentK);
if (divisorCycle == prime)
{
// A cycle equal to the tested exponent (which is prime in this path) guarantees that the candidate divides
// the corresponding Mersenne number because the order of 2 modulo the divisor is exactly p.
foundDivisor = candidate;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
divisor.Add(step);
currentK++;
residueStepper.Advance();
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
private bool CheckDivisorsLarge(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
BigInteger step,
out bool processedAll,
out BigInteger foundDivisor)
{
processedAll = true;
foundDivisor = BigInteger.Zero;
BigInteger currentK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger divisor = (step * currentK) + BigInteger.One;
if (allowedMax.IsZero)
{
processedAll = false;
return false;
}
if (divisor > allowedMax)
{
return false;
}
LastDigit lastDigit = (prime & 3UL) == 3UL ? LastDigit.Seven : LastDigit.One;
ushort decimalMask = DivisorGenerator.GetDecimalMask(lastDigit);
var rem10 = new BigIntegerCycleRemainderStepper(10);
var rem8 = new BigIntegerCycleRemainderStepper(8);
var rem5 = new BigIntegerCycleRemainderStepper(5);
var rem3 = new BigIntegerCycleRemainderStepper(3);
var rem7 = new BigIntegerCycleRemainderStepper(7);
var rem11 = new BigIntegerCycleRemainderStepper(11);
var rem13 = new BigIntegerCycleRemainderStepper(13);
var rem17 = new BigIntegerCycleRemainderStepper(17);
var rem19 = new BigIntegerCycleRemainderStepper(19);
byte remainder10 = (byte)rem10.Initialize(divisor);
byte remainder8 = (byte)rem8.Initialize(divisor);
byte remainder5 = (byte)rem5.Initialize(divisor);
byte remainder3 = (byte)rem3.Initialize(divisor);
byte remainder7 = (byte)rem7.Initialize(divisor);
byte remainder11 = (byte)rem11.Initialize(divisor);
byte remainder13 = (byte)rem13.Initialize(divisor);
byte remainder17 = (byte)rem17.Initialize(divisor);
byte remainder19 = (byte)rem19.Initialize(divisor);
while (divisor <= allowedMax)
{
bool passesSmallModuli = remainder3 != 0 && remainder5 != 0 && remainder7 != 0 && remainder11 != 0 && remainder13 != 0 && remainder17 != 0 && remainder19 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
if (MersenneNumberDivisorByDivisorTester.IsProbablePrimeBigInteger(divisor))
{
BigInteger powResult = BigInteger.ModPow(2, prime, divisor);
RecordState(StateFilePath, currentK);
if (powResult.IsOne)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
}
else
{
RecordState(StateFilePath, currentK);
}
}
currentK += BigInteger.One;
divisor += step;
remainder10 = (byte)rem10.ComputeNext(divisor);
remainder8 = (byte)rem8.ComputeNext(divisor);
remainder5 = (byte)rem5.ComputeNext(divisor);
remainder3 = (byte)rem3.ComputeNext(divisor);
remainder7 = (byte)rem7.ComputeNext(divisor);
remainder11 = (byte)rem11.ComputeNext(divisor);
remainder13 = (byte)rem13.ComputeNext(divisor);
remainder17 = (byte)rem17.ComputeNext(divisor);
remainder19 = (byte)rem19.ComputeNext(divisor);
if (divisor > allowedMax)
{
break;
}
}
processedAll = true;
foundDivisor = BigInteger.Zero;
return false;
}
private bool CheckDivisors64Range(
ulong prime,
ulong step,
ulong allowedMax,
ulong startK,
ulong endK,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
if (startK < 1UL || endK < startK)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
currentK = startK;
UInt128 step128 = step;
UInt128 allowedMax128 = allowedMax;
UInt128 startDivisor128 = (step128 * startK) + UInt128.One;
if (startDivisor128 > allowedMax128)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
UInt128 rangeLimit128 = (step128 * endK) + UInt128.One;
if (rangeLimit128 > allowedMax128)
{
rangeLimit128 = allowedMax128;
}
ulong startDivisor = (ulong)startDivisor128;
ulong rangeLimit = (ulong)rangeLimit128;
var residueStepper = new MersenneDivisorResidueStepper(prime, (GpuUInt128)step128, (GpuUInt128)startDivisor128);
return CheckDivisors64(
prime,
step,
rangeLimit,
startDivisor,
ref residueStepper,
ref currentK,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64(
ulong prime,
ulong step,
ulong limit,
ulong divisor,
ref MersenneDivisorResidueStepper residueStepper,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
bool canAdvance = step <= limit;
if (!canAdvance)
{
if (divisor <= limit && residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentCpu(
divisor,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthCpu(
divisor,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
if (divisor > limit)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong remainingIterations = ((limit - divisor) / step) + 1UL;
while (true)
{
if (residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentCpu(
divisor,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthCpu(
divisor,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(StateFilePath, currentK);
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
remainingIterations--;
if (remainingIterations == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
divisor += step;
currentK++;
residueStepper.Advance();
}
}
private void RecordState(in string path, BigInteger k)
{
if (k <= _lastSavedK)
{
return;
}
int next = _stateCounter + 1;
if (next >= PerfectNumberConstants.ByDivisorStateSaveInterval)
{
string? directory = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(directory))
{
Directory.CreateDirectory(directory);
}
File.AppendAllText(path, k.ToString(CultureInfo.InvariantCulture) + Environment.NewLine);
_stateCounter = 0;
_lastSavedK = k;
}
else
{
_stateCounter = next;
}
}
}
@@ -0,0 +1,600 @@
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Globalization;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
public struct MersenneNumberDivisorByDivisorCpuTesterWithGpuOrder() : IMersenneNumberDivisorByDivisorTester
{
public BigInteger DivisorLimit;
public BigInteger MinK = EnvironmentConfiguration.MinK;
public readonly PrimeOrderCalculatorAccelerator Accelerator = PrimeOrderCalculatorAccelerator.Rent(1);
#pragma warning disable CS8618 // StateFilePath is always set on EvenPerfectBitScanner execution path when ResumeFromState is called.
private string StateFilePath;
#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
private int _stateCounter;
private BigInteger _lastSavedK;
private GpuUInt128WorkSet _divisorScanGpuWorkSet;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResetStateTracking()
{
_stateCounter = 0;
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResumeFromState(in string stateFile, in BigInteger lastSavedK, in BigInteger minK)
{
StateFilePath = stateFile;
_lastSavedK = lastSavedK;
MinK = minK;
_stateCounter = 0;
}
public bool IsPrime(ulong prime, out bool divisorsExhausted, out BigInteger divisor)
{
BigInteger allowedMax = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisorBig(prime, DivisorLimit);
// The CPU by-divisor run always hands us primes with enormous divisor limits, so the fallback below never executes.
// if (allowedMax < 3UL)
// {
// // EvenPerfectBitScanner routes primes below the small-divisor cutoff to the GPU path, so the CPU path still sees
// // trivial candidates during targeted tests. Short-circuit here to keep those runs aligned with the production flow.
// divisorsExhausted = true;
// return true;
// }
bool composite = CheckDivisors(
prime,
allowedMax,
MinK,
out bool processedAll,
out divisor);
if (composite)
{
divisorsExhausted = true;
return false;
}
divisorsExhausted = processedAll || composite;
divisor = BigInteger.Zero;
return true;
}
public void PrepareCandidates(ulong maxPrime, in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
{
BigInteger divisorLimitBigInteger = MersenneNumberDivisorByDivisorTester.ComputeDivisorLimitFromMaxPrimeBig(maxPrime);
DivisorLimit = divisorLimitBigInteger;
ulong divisorLimit = MersenneNumberDivisorByDivisorTester.GetAllowedDivisorLimitForSpan(divisorLimitBigInteger);
int length = primes.Length;
for (int index = 0; index < length; index++)
{
allowedMaxValues[index] = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisor(primes[index], divisorLimit);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu)
{
var session = new MersenneCpuDivisorScanSessionWithGpuOrder();
session.Configure(gpu);
return session;
}
private bool CheckDivisors(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
out bool processedAll,
out BigInteger foundDivisor)
{
BigInteger normalizedMinK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger step = ((BigInteger)prime) << 1;
BigInteger firstDivisor = (step * normalizedMinK) + BigInteger.One;
bool unlimited = allowedMax.IsZero;
bool fits64 = normalizedMinK <= ulong.MaxValue && firstDivisor <= ulong.MaxValue;
bool limitFits64 = unlimited || allowedMax <= ulong.MaxValue;
if (fits64 && limitFits64)
{
ulong allowedMax64 = unlimited ? ulong.MaxValue : (ulong)allowedMax;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
foundDivisor = foundDivisor64;
return composite64;
}
if (fits64 && allowedMax > ulong.MaxValue)
{
ulong allowedMax64 = ulong.MaxValue;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
if (composite64)
{
foundDivisor = foundDivisor64;
return true;
}
BigInteger iterations = ((BigInteger)(allowedMax64 - (ulong)firstDivisor) / (ulong)step) + BigInteger.One;
BigInteger nextK = normalizedMinK + iterations;
return CheckDivisorsLarge(
prime,
allowedMax,
nextK,
step,
out processedAll,
out foundDivisor);
}
return CheckDivisorsLarge(
prime,
allowedMax,
normalizedMinK,
step,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64Bit(
ulong prime,
ulong allowedMax,
ulong minK,
out bool processedAll,
out ulong foundDivisor)
{
foundDivisor = 0UL;
ulong currentK = minK < 1UL ? 1UL : minK;
// The EvenPerfectBitScanner feeds primes >= 138,000,000 here, so allowedMax >= 3 in production runs.
// Keeping the guard commented out documents the reasoning for benchmarks and tests.
// if (allowedMax < 3UL)
// {
// return false;
// }
ref GpuUInt128WorkSet workSet = ref _divisorScanGpuWorkSet;
ref GpuUInt128 step = ref workSet.Step;
step.High = 0UL;
step.Low = prime;
step.ShiftLeft(1);
ref GpuUInt128 limit = ref workSet.Limit;
limit.High = 0UL;
limit.Low = allowedMax;
ref GpuUInt128 divisor = ref workSet.Divisor;
divisor.High = step.High;
divisor.Low = step.Low;
divisor.Add(1UL);
if (minK > 1UL)
{
GpuUInt128 offset = new(minK - 1UL);
divisor = step * offset;
divisor.Add(1UL);
}
if (divisor.CompareTo(limit) > 0)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
// Intentionally recomputes factorizations without a per-thread cache.
// The previous factor cache recorded virtually no hits and only slowed down the scan.
ulong stepHigh = step.High;
ulong stepLow = step.Low;
ulong limitHigh = limit.High;
if (stepHigh == 0UL && limitHigh == 0UL)
{
ulong maxK = allowedMax > 0UL ? (allowedMax - 1UL) / stepLow : 0UL;
if (maxK == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong startK = minK < 1UL ? 1UL : minK;
bool processedTop = true;
bool processedBottom = true;
bool composite = false;
if (startK <= maxK)
{
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
startK,
maxK,
ref currentK,
out processedTop,
out foundDivisor);
if (composite)
{
processedAll = true;
return true;
}
}
ulong lowerEnd = startK > 1UL ? startK - 1UL : 0UL;
if (lowerEnd >= 1UL && startK == 1UL)
{
lowerEnd = Math.Min(lowerEnd, maxK);
currentK = 1UL;
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
1UL,
lowerEnd,
ref currentK,
out processedBottom,
out foundDivisor);
}
processedAll = processedTop && processedBottom;
return composite;
}
PrimeOrderCalculatorAccelerator gpu = Accelerator;
var residueStepper = new MersenneDivisorResidueStepper(prime, step, divisor);
while (divisor.CompareTo(limit) <= 0)
{
if (residueStepper.IsAdmissible())
{
ulong candidate = divisor.Low;
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(candidate);
ulong divisorCycle;
// Divisors generated from 2 * k * p + 1 exceed the small-cycle snapshot when p >= 138,000,000, so the short path below never runs.
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentGpu(
candidate,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
// Divisors produced by 2 * k * p + 1 always exceed PerfectNumberConstants.MaxQForDivisorCycles
// for the exponents scanned here, so skip the unused cache fallback and compute directly.
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthGpu(
candidate,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
// A cycle equal to the tested exponent (which is prime in this path) guarantees that the candidate divides
// the corresponding Mersenne number because the order of 2 modulo the divisor is exactly p.
foundDivisor = candidate;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
divisor.Add(step);
currentK++;
residueStepper.Advance();
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
private bool CheckDivisorsLarge(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
BigInteger step,
out bool processedAll,
out BigInteger foundDivisor)
{
processedAll = true;
foundDivisor = BigInteger.Zero;
BigInteger currentK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger divisor = (step * currentK) + BigInteger.One;
if (allowedMax.IsZero)
{
processedAll = false;
return false;
}
if (divisor > allowedMax)
{
return false;
}
LastDigit lastDigit = (prime & 3UL) == 3UL ? LastDigit.Seven : LastDigit.One;
ushort decimalMask = DivisorGenerator.GetDecimalMask(lastDigit);
var rem10 = new BigIntegerCycleRemainderStepper(10);
var rem8 = new BigIntegerCycleRemainderStepper(8);
var rem5 = new BigIntegerCycleRemainderStepper(5);
var rem3 = new BigIntegerCycleRemainderStepper(3);
var rem7 = new BigIntegerCycleRemainderStepper(7);
var rem11 = new BigIntegerCycleRemainderStepper(11);
var rem13 = new BigIntegerCycleRemainderStepper(13);
var rem17 = new BigIntegerCycleRemainderStepper(17);
var rem19 = new BigIntegerCycleRemainderStepper(19);
byte remainder10 = (byte)rem10.Initialize(divisor);
byte remainder8 = (byte)rem8.Initialize(divisor);
byte remainder5 = (byte)rem5.Initialize(divisor);
byte remainder3 = (byte)rem3.Initialize(divisor);
byte remainder7 = (byte)rem7.Initialize(divisor);
byte remainder11 = (byte)rem11.Initialize(divisor);
byte remainder13 = (byte)rem13.Initialize(divisor);
byte remainder17 = (byte)rem17.Initialize(divisor);
byte remainder19 = (byte)rem19.Initialize(divisor);
while (divisor <= allowedMax)
{
bool passesSmallModuli = remainder3 != 0 && remainder5 != 0 && remainder7 != 0 && remainder11 != 0 && remainder13 != 0 && remainder17 != 0 && remainder19 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
if (MersenneNumberDivisorByDivisorTester.IsProbablePrimeBigInteger(divisor))
{
BigInteger powResult = BigInteger.ModPow(2, prime, divisor);
RecordState(currentK);
if (powResult.IsOne)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
}
else
{
RecordState(currentK);
}
}
currentK += BigInteger.One;
divisor += step;
remainder10 = (byte)rem10.ComputeNext(divisor);
remainder8 = (byte)rem8.ComputeNext(divisor);
remainder5 = (byte)rem5.ComputeNext(divisor);
remainder3 = (byte)rem3.ComputeNext(divisor);
remainder7 = (byte)rem7.ComputeNext(divisor);
remainder11 = (byte)rem11.ComputeNext(divisor);
remainder13 = (byte)rem13.ComputeNext(divisor);
remainder17 = (byte)rem17.ComputeNext(divisor);
remainder19 = (byte)rem19.ComputeNext(divisor);
if (divisor > allowedMax)
{
break;
}
}
processedAll = true;
foundDivisor = BigInteger.Zero;
return false;
}
private bool CheckDivisors64Range(
ulong prime,
ulong step,
ulong allowedMax,
ulong startK,
ulong endK,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
if (startK < 1UL || endK < startK)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
currentK = startK;
UInt128 step128 = step;
UInt128 allowedMax128 = allowedMax;
UInt128 startDivisor128 = (step128 * startK) + UInt128.One;
if (startDivisor128 > allowedMax128)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
UInt128 rangeLimit128 = (step128 * endK) + UInt128.One;
if (rangeLimit128 > allowedMax128)
{
rangeLimit128 = allowedMax128;
}
ulong startDivisor = (ulong)startDivisor128;
ulong rangeLimit = (ulong)rangeLimit128;
var residueStepper = new MersenneDivisorResidueStepper(prime, (GpuUInt128)step128, (GpuUInt128)startDivisor128);
return CheckDivisors64(
prime,
step,
rangeLimit,
startDivisor,
ref residueStepper,
ref currentK,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64(
ulong prime,
ulong step,
ulong limit,
ulong divisor,
ref MersenneDivisorResidueStepper residueStepper,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
PrimeOrderCalculatorAccelerator gpu = Accelerator;
if (step > limit)
{
if (divisor <= limit && residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentGpu(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthGpu(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
if (divisor > limit)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong remainingIterations = ((limit - divisor) / step) + 1UL;
while (true)
{
if (residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentGpu(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthGpu(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
remainingIterations--;
if (remainingIterations == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
divisor += step;
currentK++;
residueStepper.Advance();
}
}
private void RecordState(BigInteger k)
{
string path = StateFilePath;
if (k <= _lastSavedK)
{
return;
}
int next = _stateCounter + 1;
if (next >= PerfectNumberConstants.ByDivisorStateSaveInterval)
{
string? directory = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(directory))
{
Directory.CreateDirectory(directory);
}
File.AppendAllText(path, k.ToString(CultureInfo.InvariantCulture) + Environment.NewLine);
_stateCounter = 0;
_lastSavedK = k;
}
else
{
_stateCounter = next;
}
}
}
@@ -0,0 +1,598 @@
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Globalization;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
public struct MersenneNumberDivisorByDivisorCpuTesterWithHybridOrder() : IMersenneNumberDivisorByDivisorTester
{
public BigInteger DivisorLimit;
public BigInteger MinK = EnvironmentConfiguration.MinK;
public readonly PrimeOrderCalculatorAccelerator Accelerator = PrimeOrderCalculatorAccelerator.Rent(1);
#pragma warning disable CS8618 // StateFilePath is always set on EvenPerfectBitScanner execution path when ResumeFromState is called.
private string StateFilePath;
#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
private int _stateCounter;
private BigInteger _lastSavedK;
private GpuUInt128WorkSet _divisorScanGpuWorkSet;
public void ResetStateTracking()
{
_stateCounter = 0;
}
public void ResumeFromState(in string stateFile, in BigInteger lastSavedK, in BigInteger minK)
{
StateFilePath = stateFile;
_lastSavedK = lastSavedK;
MinK = minK;
_stateCounter = 0;
}
public bool IsPrime(ulong prime, out bool divisorsExhausted, out BigInteger divisor)
{
BigInteger allowedMax = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisorBig(prime, DivisorLimit);
// The CPU by-divisor run always hands us primes with enormous divisor limits, so the fallback below never executes.
// if (allowedMax < 3UL)
// {
// // EvenPerfectBitScanner routes primes below the small-divisor cutoff to the GPU path, so the CPU path still sees
// // trivial candidates during targeted tests. Short-circuit here to keep those runs aligned with the production flow.
// divisorsExhausted = true;
// return true;
// }
bool composite = CheckDivisors(
prime,
allowedMax,
MinK,
out bool processedAll,
out divisor);
if (composite)
{
divisorsExhausted = true;
return false;
}
divisorsExhausted = processedAll || composite;
divisor = BigInteger.Zero;
return true;
}
public void PrepareCandidates(ulong maxPrime, in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
{
BigInteger divisorLimitBigInteger = MersenneNumberDivisorByDivisorTester.ComputeDivisorLimitFromMaxPrimeBig(maxPrime);
DivisorLimit = divisorLimitBigInteger;
ulong divisorLimit = MersenneNumberDivisorByDivisorTester.GetAllowedDivisorLimitForSpan(divisorLimitBigInteger);
int length = primes.Length;
for (int index = 0; index < length; index++)
{
allowedMaxValues[index] = MersenneNumberDivisorByDivisorTester.ComputeAllowedMaxDivisor(primes[index], divisorLimit);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public readonly IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu)
{
var session = new MersenneCpuDivisorScanSessionWithHybridOrder();
session.Configure(gpu);
return session;
}
private bool CheckDivisors(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
out bool processedAll,
out BigInteger foundDivisor)
{
BigInteger normalizedMinK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger step = ((BigInteger)prime) << 1;
BigInteger firstDivisor = (step * normalizedMinK) + BigInteger.One;
bool unlimited = allowedMax.IsZero;
bool fits64 = normalizedMinK <= ulong.MaxValue && firstDivisor <= ulong.MaxValue;
bool limitFits64 = unlimited || allowedMax <= ulong.MaxValue;
if (fits64 && limitFits64)
{
ulong allowedMax64 = unlimited ? ulong.MaxValue : (ulong)allowedMax;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
foundDivisor = foundDivisor64;
return composite64;
}
if (fits64 && allowedMax > ulong.MaxValue)
{
ulong allowedMax64 = ulong.MaxValue;
bool composite64 = CheckDivisors64Bit(
prime,
allowedMax64,
(ulong)normalizedMinK,
out processedAll,
out ulong foundDivisor64);
if (composite64)
{
foundDivisor = foundDivisor64;
return true;
}
BigInteger iterations = ((BigInteger)(allowedMax64 - (ulong)firstDivisor) / (ulong)step) + BigInteger.One;
BigInteger nextK = normalizedMinK + iterations;
return CheckDivisorsLarge(
prime,
allowedMax,
nextK,
step,
out processedAll,
out foundDivisor);
}
return CheckDivisorsLarge(
prime,
allowedMax,
normalizedMinK,
step,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64Bit(
ulong prime,
ulong allowedMax,
ulong minK,
out bool processedAll,
out ulong foundDivisor)
{
foundDivisor = 0UL;
ulong currentK = minK < 1UL ? 1UL : minK;
// The EvenPerfectBitScanner feeds primes >= 138,000,000 here, so allowedMax >= 3 in production runs.
// Keeping the guard commented out documents the reasoning for benchmarks and tests.
// if (allowedMax < 3UL)
// {
// return false;
// }
ref GpuUInt128WorkSet workSet = ref _divisorScanGpuWorkSet;
ref GpuUInt128 step = ref workSet.Step;
step.High = 0UL;
step.Low = prime;
step.ShiftLeft(1);
ref GpuUInt128 limit = ref workSet.Limit;
limit.High = 0UL;
limit.Low = allowedMax;
ref GpuUInt128 divisor = ref workSet.Divisor;
divisor.High = step.High;
divisor.Low = step.Low;
divisor.Add(1UL);
if (minK > 1UL)
{
GpuUInt128 offset = new(minK - 1UL);
divisor = step * offset;
divisor.Add(1UL);
}
if (divisor.CompareTo(limit) > 0)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
// Intentionally recomputes factorizations without a per-thread cache.
// The previous factor cache recorded virtually no hits and only slowed down the scan.
ulong stepHigh = step.High;
ulong stepLow = step.Low;
ulong limitHigh = limit.High;
if (stepHigh == 0UL && limitHigh == 0UL)
{
ulong maxK = allowedMax > 0UL ? (allowedMax - 1UL) / stepLow : 0UL;
if (maxK == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong startK = minK < 1UL ? 1UL : minK;
bool processedTop = true;
bool processedBottom = true;
bool composite = false;
if (startK <= maxK)
{
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
startK,
maxK,
ref currentK,
out processedTop,
out foundDivisor);
if (composite)
{
processedAll = true;
return true;
}
}
ulong lowerEnd = startK > 1UL ? startK - 1UL : 0UL;
if (lowerEnd >= 1UL && startK == 1UL)
{
lowerEnd = Math.Min(lowerEnd, maxK);
currentK = 1UL;
composite = CheckDivisors64Range(
prime,
stepLow,
allowedMax,
1UL,
lowerEnd,
ref currentK,
out processedBottom,
out foundDivisor);
}
processedAll = processedTop && processedBottom;
return composite;
}
PrimeOrderCalculatorAccelerator gpu = Accelerator;
var residueStepper = new MersenneDivisorResidueStepper(prime, step, divisor);
while (divisor.CompareTo(limit) <= 0)
{
if (residueStepper.IsAdmissible())
{
ulong candidate = divisor.Low;
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(candidate);
ulong divisorCycle;
// Divisors generated from 2 * k * p + 1 exceed the small-cycle snapshot when p >= 138,000,000, so the short path below never runs.
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentHybrid(
candidate,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
// Divisors produced by 2 * k * p + 1 always exceed PerfectNumberConstants.MaxQForDivisorCycles
// for the exponents scanned here, so skip the unused cache fallback and compute directly.
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthHybrid(
candidate,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
// A cycle equal to the tested exponent (which is prime in this path) guarantees that the candidate divides
// the corresponding Mersenne number because the order of 2 modulo the divisor is exactly p.
foundDivisor = candidate;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
divisor.Add(step);
currentK++;
residueStepper.Advance();
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
private bool CheckDivisorsLarge(
ulong prime,
BigInteger allowedMax,
BigInteger minK,
BigInteger step,
out bool processedAll,
out BigInteger foundDivisor)
{
processedAll = true;
foundDivisor = BigInteger.Zero;
BigInteger currentK = minK < BigInteger.One ? BigInteger.One : minK;
BigInteger divisor = (step * currentK) + BigInteger.One;
if (allowedMax.IsZero)
{
processedAll = false;
return false;
}
if (divisor > allowedMax)
{
return false;
}
LastDigit lastDigit = (prime & 3UL) == 3UL ? LastDigit.Seven : LastDigit.One;
ushort decimalMask = DivisorGenerator.GetDecimalMask(lastDigit);
var rem10 = new BigIntegerCycleRemainderStepper(10);
var rem8 = new BigIntegerCycleRemainderStepper(8);
var rem5 = new BigIntegerCycleRemainderStepper(5);
var rem3 = new BigIntegerCycleRemainderStepper(3);
var rem7 = new BigIntegerCycleRemainderStepper(7);
var rem11 = new BigIntegerCycleRemainderStepper(11);
var rem13 = new BigIntegerCycleRemainderStepper(13);
var rem17 = new BigIntegerCycleRemainderStepper(17);
var rem19 = new BigIntegerCycleRemainderStepper(19);
byte remainder10 = (byte)rem10.Initialize(divisor);
byte remainder8 = (byte)rem8.Initialize(divisor);
byte remainder5 = (byte)rem5.Initialize(divisor);
byte remainder3 = (byte)rem3.Initialize(divisor);
byte remainder7 = (byte)rem7.Initialize(divisor);
byte remainder11 = (byte)rem11.Initialize(divisor);
byte remainder13 = (byte)rem13.Initialize(divisor);
byte remainder17 = (byte)rem17.Initialize(divisor);
byte remainder19 = (byte)rem19.Initialize(divisor);
while (divisor <= allowedMax)
{
bool passesSmallModuli = remainder3 != 0 && remainder5 != 0 && remainder7 != 0 && remainder11 != 0 && remainder13 != 0 && remainder17 != 0 && remainder19 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
if (MersenneNumberDivisorByDivisorTester.IsProbablePrimeBigInteger(divisor))
{
BigInteger powResult = BigInteger.ModPow(2, prime, divisor);
RecordState(currentK);
if (powResult.IsOne)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
}
else
{
RecordState(currentK);
}
}
currentK += BigInteger.One;
divisor += step;
remainder10 = (byte)rem10.ComputeNext(divisor);
remainder8 = (byte)rem8.ComputeNext(divisor);
remainder5 = (byte)rem5.ComputeNext(divisor);
remainder3 = (byte)rem3.ComputeNext(divisor);
remainder7 = (byte)rem7.ComputeNext(divisor);
remainder11 = (byte)rem11.ComputeNext(divisor);
remainder13 = (byte)rem13.ComputeNext(divisor);
remainder17 = (byte)rem17.ComputeNext(divisor);
remainder19 = (byte)rem19.ComputeNext(divisor);
if (divisor > allowedMax)
{
break;
}
}
processedAll = true;
foundDivisor = BigInteger.Zero;
return false;
}
private bool CheckDivisors64Range(
ulong prime,
ulong step,
ulong allowedMax,
ulong startK,
ulong endK,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
if (startK < 1UL || endK < startK)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
currentK = startK;
UInt128 step128 = step;
UInt128 allowedMax128 = allowedMax;
UInt128 startDivisor128 = (step128 * startK) + UInt128.One;
if (startDivisor128 > allowedMax128)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
UInt128 rangeLimit128 = (step128 * endK) + UInt128.One;
if (rangeLimit128 > allowedMax128)
{
rangeLimit128 = allowedMax128;
}
ulong startDivisor = (ulong)startDivisor128;
ulong rangeLimit = (ulong)rangeLimit128;
var residueStepper = new MersenneDivisorResidueStepper(prime, (GpuUInt128)step128, (GpuUInt128)startDivisor128);
return CheckDivisors64(
prime,
step,
rangeLimit,
startDivisor,
ref residueStepper,
ref currentK,
out processedAll,
out foundDivisor);
}
private bool CheckDivisors64(
ulong prime,
ulong step,
ulong limit,
ulong divisor,
ref MersenneDivisorResidueStepper residueStepper,
ref ulong currentK,
out bool processedAll,
out ulong foundDivisor)
{
PrimeOrderCalculatorAccelerator gpu = Accelerator;
bool canAdvance = step <= limit;
if (!canAdvance)
{
if (divisor <= limit && residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentHybrid(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthHybrid(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
processedAll = true;
foundDivisor = 0UL;
return false;
}
if (divisor > limit)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
ulong remainingIterations = ((limit - divisor) / step) + 1UL;
while (true)
{
if (residueStepper.IsAdmissible())
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneNumberDivisorByDivisorTester.TryCalculateCycleLengthForExponentHybrid(
divisor,
gpu,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
divisorCycle = MersenneNumberDivisorByDivisorTester.CalculateCycleLengthHybrid(
divisor,
gpu,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
RecordState(currentK);
if (divisorCycle == prime)
{
foundDivisor = divisor;
processedAll = true;
return true;
}
if (divisorCycle == 0UL)
{
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
}
}
remainingIterations--;
if (remainingIterations == 0UL)
{
processedAll = true;
foundDivisor = 0UL;
return false;
}
divisor += step;
currentK++;
residueStepper.Advance();
}
}
private void RecordState(BigInteger k)
{
string path = StateFilePath;
if (k <= _lastSavedK)
{
return;
}
int next = _stateCounter + 1;
if (next >= PerfectNumberConstants.ByDivisorStateSaveInterval)
{
string? directory = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(directory))
{
Directory.CreateDirectory(directory);
}
File.AppendAllText(path, k.ToString(CultureInfo.InvariantCulture) + Environment.NewLine);
_stateCounter = 0;
_lastSavedK = k;
}
else
{
_stateCounter = next;
}
}
}
@@ -0,0 +1,88 @@
using System.Globalization;
using System.Numerics;
using PerfectNumbers.Core.Gpu;
namespace PerfectNumbers.Core.Cpu;
internal struct MersenneNumberDivisorByDivisorPrimeScanSessionWithCpuOrder(
in MersenneNumberDivisorByDivisorCpuTesterWithCpuOrder prototype,
Action markComposite,
Action clearComposite,
Action<ulong, bool, bool, bool, BigInteger> printResult)
{
private MersenneNumberDivisorByDivisorCpuTesterWithCpuOrder _tester = new()
{
DivisorLimit = prototype.DivisorLimit,
MinK = EnvironmentConfiguration.MinK,
};
private MersenneCpuDivisorScanSessionWithCpuOrder _divisorScanSession = new();
private readonly Action _markComposite = markComposite;
private readonly Action _clearComposite = clearComposite;
private readonly Action<ulong, bool, bool, bool, BigInteger> _printResult = printResult;
public void ProcessPrime(ulong prime)
{
try
{
Console.WriteLine($"Processing {prime}");
string stateFile = Path.Combine(
PerfectNumberConstants.ByDivisorStateDirectory,
prime.ToString(CultureInfo.InvariantCulture) + ".bin");
ConfigureForPrime(stateFile);
bool isPrime = _tester.IsPrime(prime, out bool divisorsExhausted, out BigInteger divisor);
if (!isPrime)
{
if (!string.IsNullOrEmpty(stateFile) && File.Exists(stateFile))
{
File.Delete(stateFile);
}
_markComposite();
_printResult(prime, true, true, false, divisor);
Console.WriteLine($"Finished processing {prime}");
return;
}
_clearComposite();
_printResult(prime, true, divisorsExhausted, true, divisor);
Console.WriteLine($"Finished processing {prime}");
}
catch (Exception ex)
{
Console.WriteLine($"Error processing {ex.Message} {ex.StackTrace}");
Environment.Exit(1);
}
}
private void ConfigureForPrime(string stateFile)
{
BigInteger resumeK = EnvironmentConfiguration.MinK;
if (File.Exists(stateFile))
{
if (MersenneNumberDivisorByDivisorTester.TryReadLastSavedK(stateFile, out BigInteger lastK))
{
resumeK = lastK + BigInteger.One;
_tester.ResumeFromState(stateFile, lastK, resumeK);
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
_tester.ResetStateTracking();
}
public void Dispose()
{
}
}
@@ -0,0 +1,101 @@
using System.Globalization;
using System.Numerics;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
internal struct MersenneNumberDivisorByDivisorPrimeScanSessionWithGpuOrder
{
private MersenneNumberDivisorByDivisorCpuTesterWithGpuOrder _tester;
private MersenneCpuDivisorScanSessionWithGpuOrder _divisorScanSession;
private readonly Action _markComposite;
private readonly Action _clearComposite;
private readonly Action<ulong, bool, bool, bool, BigInteger> _printResult;
public MersenneNumberDivisorByDivisorPrimeScanSessionWithGpuOrder(
in MersenneNumberDivisorByDivisorCpuTesterWithGpuOrder prototype,
Action markComposite,
Action clearComposite,
Action<ulong, bool, bool, bool, BigInteger> printResult)
{
_tester = new MersenneNumberDivisorByDivisorCpuTesterWithGpuOrder
{
DivisorLimit = prototype.DivisorLimit,
MinK = EnvironmentConfiguration.MinK,
};
_divisorScanSession = new MersenneCpuDivisorScanSessionWithGpuOrder();
_divisorScanSession.Configure(_tester.Accelerator);
_markComposite = markComposite;
_clearComposite = clearComposite;
_printResult = printResult;
}
public void ProcessPrime(ulong prime)
{
try
{
Console.WriteLine($"Processing {prime}");
string stateFile = Path.Combine(
PerfectNumberConstants.ByDivisorStateDirectory,
prime.ToString(CultureInfo.InvariantCulture) + ".bin");
ConfigureForPrime(stateFile);
bool isPrime = _tester.IsPrime(prime, out bool divisorsExhausted, out BigInteger divisor);
if (!isPrime)
{
if (!string.IsNullOrEmpty(stateFile) && File.Exists(stateFile))
{
File.Delete(stateFile);
}
_markComposite();
_printResult(prime, true, true, false, divisor);
Console.WriteLine($"Finished processing {prime}");
return;
}
_clearComposite();
_printResult(prime, true, divisorsExhausted, true, divisor);
Console.WriteLine($"Finished processing {prime}");
}
catch (Exception ex)
{
Console.WriteLine($"Error processing {ex.Message} {ex.StackTrace}");
Environment.Exit(1);
}
}
private void ConfigureForPrime(string stateFile)
{
BigInteger resumeK = EnvironmentConfiguration.MinK;
if (File.Exists(stateFile))
{
if (MersenneNumberDivisorByDivisorTester.TryReadLastSavedK(stateFile, out BigInteger lastK))
{
resumeK = lastK + BigInteger.One;
_tester.ResumeFromState(stateFile, lastK, resumeK);
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
_tester.ResetStateTracking();
}
public void Dispose()
{
PrimeOrderCalculatorAccelerator.Return(_tester.Accelerator);
}
}
@@ -0,0 +1,101 @@
using System.Globalization;
using System.Numerics;
using PerfectNumbers.Core.Gpu;
using PerfectNumbers.Core.Gpu.Accelerators;
namespace PerfectNumbers.Core.Cpu;
internal struct MersenneNumberDivisorByDivisorPrimeScanSessionWithHybridOrder
{
private MersenneNumberDivisorByDivisorCpuTesterWithHybridOrder _tester;
private MersenneCpuDivisorScanSessionWithHybridOrder _divisorScanSession;
private readonly Action _markComposite;
private readonly Action _clearComposite;
private readonly Action<ulong, bool, bool, bool, BigInteger> _printResult;
public MersenneNumberDivisorByDivisorPrimeScanSessionWithHybridOrder(
in MersenneNumberDivisorByDivisorCpuTesterWithHybridOrder prototype,
Action markComposite,
Action clearComposite,
Action<ulong, bool, bool, bool, BigInteger> printResult)
{
_tester = new MersenneNumberDivisorByDivisorCpuTesterWithHybridOrder
{
DivisorLimit = prototype.DivisorLimit,
MinK = EnvironmentConfiguration.MinK,
};
_divisorScanSession = new MersenneCpuDivisorScanSessionWithHybridOrder();
_divisorScanSession.Configure(_tester.Accelerator);
_markComposite = markComposite;
_clearComposite = clearComposite;
_printResult = printResult;
}
public void ProcessPrime(ulong prime)
{
try
{
Console.WriteLine($"Processing {prime}");
string stateFile = Path.Combine(
PerfectNumberConstants.ByDivisorStateDirectory,
prime.ToString(CultureInfo.InvariantCulture) + ".bin");
ConfigureForPrime(stateFile);
bool isPrime = _tester.IsPrime(prime, out bool divisorsExhausted, out BigInteger divisor);
if (!isPrime)
{
if (!string.IsNullOrEmpty(stateFile) && File.Exists(stateFile))
{
File.Delete(stateFile);
}
_markComposite();
_printResult(prime, true, true, false, divisor);
Console.WriteLine($"Finished processing {prime}");
return;
}
_clearComposite();
_printResult(prime, true, divisorsExhausted, true, divisor);
Console.WriteLine($"Finished processing {prime}");
}
catch (Exception ex)
{
Console.WriteLine($"Error processing {ex.Message} {ex.StackTrace}");
Environment.Exit(1);
}
}
private void ConfigureForPrime(string stateFile)
{
BigInteger resumeK = EnvironmentConfiguration.MinK;
if (File.Exists(stateFile))
{
if (MersenneNumberDivisorByDivisorTester.TryReadLastSavedK(stateFile, out BigInteger lastK))
{
resumeK = lastK + BigInteger.One;
_tester.ResumeFromState(stateFile, lastK, resumeK);
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
_tester.ResetStateTracking();
}
public void Dispose()
{
PrimeOrderCalculatorAccelerator.Return(_tester.Accelerator);
}
}
+3 -3
View File
@@ -4,7 +4,7 @@ namespace PerfectNumbers.Core;
public struct CycleRemainderStepper(ulong cycleLength)
{
private readonly ulong _cycleLength = cycleLength;
public ulong CycleLength = cycleLength;
private ulong _previousPrime = 0UL;
private ulong _currentRemainder = 0UL;
@@ -18,7 +18,7 @@ public struct CycleRemainderStepper(ulong cycleLength)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ulong Initialize(ulong prime)
{
ulong cycleLength = _cycleLength;
ulong cycleLength = CycleLength;
ulong remainder = prime.ReduceCycleRemainder(cycleLength);
_previousPrime = prime;
@@ -29,7 +29,7 @@ public struct CycleRemainderStepper(ulong cycleLength)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ulong ComputeNext(ulong prime)
{
ulong cycleLength = _cycleLength;
ulong cycleLength = CycleLength;
ulong delta = prime - _previousPrime;
_previousPrime = prime;
@@ -0,0 +1,31 @@
using System.Numerics;
using System.Runtime.CompilerServices;
using PerfectNumbers.Core.Gpu;
namespace PerfectNumbers.Core;
#pragma warning disable CA2211 // The fields are settable on purpose for the best performance
public static class EnvironmentConfiguration
{
public static ulong DivisorLimit = ulong.MaxValue;
public static int GpuBatchSize = GpuConstants.ScanBatchSize;
public static int GpuRatio = PerfectNumberConstants.GpuRatio;
public static BigInteger MinK = BigInteger.One;
public static ComputationDevice OrderDevice = ComputationDevice.Cpu;
public static int RollingAccelerators = PerfectNumberConstants.RollingAccelerators;
public static string? StateFilePath;
public static bool UseGpuOrder;
public static bool UseHybridOrder;
public static bool UseCpuOrder;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public static void Initialize()
{
UseGpuOrder = OrderDevice == ComputationDevice.Gpu;
UseHybridOrder = OrderDevice == ComputationDevice.Hybrid;
UseCpuOrder = OrderDevice == ComputationDevice.Cpu;
}
}
#pragma warning restore CA2211 // Non-constant fields should not be visible
+1 -1
View File
@@ -48,7 +48,7 @@ namespace PerfectNumbers.Core.Gpu
}
}
public static readonly AcceleratorPool Shared = new(PerfectNumberConstants.RollingAccelerators);
public static readonly AcceleratorPool Shared = new(EnvironmentConfiguration.RollingAccelerators);
private readonly int Capacity;
@@ -6,8 +6,8 @@ namespace PerfectNumbers.Core.Gpu.Accelerators;
public static class AcceleratorStreamPool
{
private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
private static readonly PollingSemaphore[] _locks = new PollingSemaphore[PerfectNumberConstants.RollingAccelerators];
private static readonly ConcurrentFixedCapacityStack<AcceleratorStream>[] _streams = new ConcurrentFixedCapacityStack<AcceleratorStream>[PerfectNumberConstants.RollingAccelerators];
private static readonly PollingSemaphore[] _locks = new PollingSemaphore[EnvironmentConfiguration.RollingAccelerators];
private static readonly ConcurrentFixedCapacityStack<AcceleratorStream>[] _streams = new ConcurrentFixedCapacityStack<AcceleratorStream>[EnvironmentConfiguration.RollingAccelerators];
private static PollingSemaphore CreateLock() => new(PerfectNumberConstants.ThreadsByAccelerator, TimeSpan.FromMilliseconds(1000), 1);
@@ -8,7 +8,7 @@ internal readonly struct HeuristicCombinedGpuTables
{
private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
private static readonly HeuristicCombinedGpuTables[] _sharedTables = new HeuristicCombinedGpuTables[PerfectNumberConstants.RollingAccelerators];
private static readonly HeuristicCombinedGpuTables[] _sharedTables = new HeuristicCombinedGpuTables[EnvironmentConfiguration.RollingAccelerators];
[MethodImpl(MethodImplOptions.AggressiveOptimization)]
internal static void WarmUp(int acceleratorIndex, AcceleratorStream stream) => _sharedTables[acceleratorIndex] = new(_accelerators[acceleratorIndex], stream);
@@ -7,9 +7,9 @@ internal sealed class HeuristicGroupABGpuTables
{
private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
private static readonly HeuristicGroupABGpuTables[] _sharedTables = new HeuristicGroupABGpuTables[PerfectNumberConstants.RollingAccelerators];
private static readonly HeuristicGroupABGpuTables[] _sharedTables = new HeuristicGroupABGpuTables[EnvironmentConfiguration.RollingAccelerators];
private static readonly SemaphoreSlim[] _locks = [..Enumerable.Range(1, PerfectNumberConstants.RollingAccelerators).Select(_ => new SemaphoreSlim(1))];
private static readonly SemaphoreSlim[] _locks = [..Enumerable.Range(1, EnvironmentConfiguration.RollingAccelerators).Select(_ => new SemaphoreSlim(1))];
internal static HeuristicGroupABGpuTables EnsureStaticTables(int acceleratorIndex, AcceleratorStream stream)
{
@@ -7,7 +7,7 @@ namespace PerfectNumbers.Core.Gpu.Accelerators;
internal readonly struct LastDigitGpuTables
{
private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
private static readonly LastDigitGpuTables[] _sharedTables = new LastDigitGpuTables[PerfectNumberConstants.RollingAccelerators];
private static readonly LastDigitGpuTables[] _sharedTables = new LastDigitGpuTables[EnvironmentConfiguration.RollingAccelerators];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static LastDigitGpuTables GetStaticTables(int acceleratorIndex) => _sharedTables[acceleratorIndex];
@@ -9,6 +9,8 @@ public static class GpuPrimeWorkLimiter
public static void Acquire() => _semaphore.Wait();
public static void Release() => _semaphore.Release();
public static int CurrentLimit => _currentLimit;
public static void SetLimit(int value)
{
if (value <= 0)
@@ -0,0 +1,95 @@
using System.Globalization;
using System.Numerics;
namespace PerfectNumbers.Core.Gpu;
internal struct MersenneNumberDivisorByDivisorGpuPrimeScanSession
{
private readonly MersenneNumberDivisorByDivisorGpuTester _tester;
private readonly ulong _divisorLimit;
private readonly Action _markComposite;
private readonly Action _clearComposite;
private readonly Action<ulong, bool, bool, bool, BigInteger> _printResult;
public MersenneNumberDivisorByDivisorGpuPrimeScanSession(
MersenneNumberDivisorByDivisorGpuTester prototype,
Action markComposite,
Action clearComposite,
Action<ulong, bool, bool, bool, BigInteger> printResult)
{
_tester = new MersenneNumberDivisorByDivisorGpuTester
{
MinK = EnvironmentConfiguration.MinK,
};
_divisorLimit = prototype.DivisorLimit;
_tester.SetDivisorLimitForClone(_divisorLimit);
_markComposite = markComposite;
_clearComposite = clearComposite;
_printResult = printResult;
}
public void ProcessPrime(ulong prime)
{
try
{
Console.WriteLine($"Processing {prime}");
string stateFile = Path.Combine(
PerfectNumberConstants.ByDivisorStateDirectory,
prime.ToString(CultureInfo.InvariantCulture) + ".bin");
ConfigureForPrime(stateFile);
bool isPrime = _tester.IsPrime(prime, out bool divisorsExhausted, out BigInteger divisor);
if (!isPrime)
{
if (!string.IsNullOrEmpty(stateFile) && File.Exists(stateFile))
{
File.Delete(stateFile);
}
_markComposite();
_printResult(prime, true, true, false, divisor);
Console.WriteLine($"Finished processing {prime}");
return;
}
_clearComposite();
_printResult(prime, true, divisorsExhausted, true, divisor);
Console.WriteLine($"Finished processing {prime}");
}
catch (Exception ex)
{
Console.WriteLine($"Error processing {ex.Message} {ex.StackTrace}");
Environment.Exit(1);
}
}
private void ConfigureForPrime(string stateFile)
{
BigInteger resumeK = EnvironmentConfiguration.MinK;
if (File.Exists(stateFile))
{
if (MersenneNumberDivisorByDivisorTester.TryReadLastSavedK(stateFile, out BigInteger lastK))
{
resumeK = lastK + BigInteger.One;
_tester.ResumeFromState(stateFile, lastK, resumeK);
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
}
else
{
_tester.ResumeFromState(stateFile, BigInteger.Zero, resumeK);
}
_tester.ResetStateTracking();
}
public void Dispose()
{
}
}
@@ -14,67 +14,46 @@ namespace PerfectNumbers.Core.Gpu;
/// </summary>
public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDivisorByDivisorTester
{
private int _gpuBatchSize = GpuConstants.ScanBatchSize;
// EvenPerfectBitScanner configures the GPU tester once before scanning and never mutates the configuration afterwards,
// so the synchronization fields from the previous implementation remain commented out here.
private readonly PrimeOrderCalculatorAccelerator Accelerator = PrimeOrderCalculatorAccelerator.Rent(1);
private ulong _divisorLimit;
private BigInteger _minK = BigInteger.One;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
internal void SetDivisorLimitForClone(ulong divisorLimit) => _divisorLimit = divisorLimit;
public BigInteger MinK = BigInteger.One;
public string? StateFilePath;
private readonly ConcurrentFixedCapacityStack<MersenneNumberDivisorByDivisorAccelerator>[] _resourcePool = [.. AcceleratorPool.Shared.Accelerators.Select(x => new ConcurrentFixedCapacityStack<MersenneNumberDivisorByDivisorAccelerator>(PerfectNumberConstants.DefaultPoolCapacity))];
private readonly ConcurrentFixedCapacityStack<DivisorScanSession> _sessionPool = new(PerfectNumberConstants.DefaultPoolCapacity);
public int GpuBatchSize
{
get => _gpuBatchSize;
set => _gpuBatchSize = value < 1 ? 1 : value;
}
int IMersenneNumberDivisorByDivisorTester.BatchSize
{
get => GpuBatchSize;
set => GpuBatchSize = value;
}
public BigInteger MinK
{
get => _minK;
set => _minK = value < BigInteger.One ? BigInteger.One : value;
}
public string? StateFilePath { get; set; }
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResetStateTracking()
{
}
public void ResumeFromState(BigInteger lastSavedK)
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public void ResumeFromState(in string stateFile, in BigInteger lastSavedK, in BigInteger minK)
{
StateFilePath = stateFile;
if (lastSavedK > ulong.MaxValue)
{
throw new NotSupportedException("GPU by-divisor tester does not support MinK above UInt64.");
ThrowNotSupportedLastSavedK();
return; // We'll never get to here
}
_minK = lastSavedK + BigInteger.One;
MinK = minK;
}
public void ConfigureFromMaxPrime(ulong maxPrime)
{
// EvenPerfectBitScanner configures the GPU tester once before scanning and never mutates the configuration afterwards,
// so synchronization and runtime configuration guards are unnecessary here.
private static void ThrowNotSupportedLastSavedK() => throw new NotSupportedException("GPU by-divisor tester does not support MinK above UInt64.");
_divisorLimit = ComputeDivisorLimitFromMaxPrimeGpu(maxPrime);
}
public bool IsPrime(PrimeOrderCalculatorAccelerator gpu, ulong prime, out bool divisorsExhausted, out BigInteger divisor)
public bool IsPrime(ulong prime, out bool divisorsExhausted, out BigInteger divisor)
{
ulong allowedMax;
int batchCapacity;
// EvenPerfectBitScanner only calls into this tester after configuring it once, so we can read the cached values without locking.
allowedMax = ComputeAllowedMaxDivisorGpu(prime, _divisorLimit);
batchCapacity = _gpuBatchSize;
// Production scans never shrink the divisor window below three, so this guard stays commented out.
// if (allowedMax < 3UL)
@@ -84,17 +63,16 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
// }
bool composite;
bool coveredRange;
ulong lastProcessed;
// GpuPrimeWorkLimiter();
// int acceleratorIndex = AcceleratorPool.Shared.Rent();
// var accelerator = _accelerators[acceleratorIndex];
PrimeOrderCalculatorAccelerator gpu = Accelerator;
var acceleratorIndex = gpu.AcceleratorIndex;
// Monitor.Enter(gpuLease.ExecutionLock);
var resources = RentBatchResources(acceleratorIndex, batchCapacity);
var resources = RentBatchResources(acceleratorIndex, EnvironmentConfiguration.GpuBatchSize);
composite = CheckDivisors(
gpu,
@@ -115,8 +93,8 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
resources.Offsets,
resources.Counts,
resources.Cycles,
out lastProcessed,
out coveredRange);
out ulong lastProcessed,
out bool coveredRange);
ReturnBatchResources(acceleratorIndex, resources);
// Monitor.Exit(gpuLease.ExecutionLock);
@@ -134,17 +112,19 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
private ulong GetMinKOrThrow()
{
if (_minK > ulong.MaxValue)
if (MinK > ulong.MaxValue)
{
throw new NotSupportedException("GPU by-divisor tester does not support MinK above UInt64.");
ThrowNotSupportedLastSavedK();
return 0UL;
}
return (ulong)_minK;
return (ulong)MinK;
}
public void PrepareCandidates(in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
public void PrepareCandidates(ulong maxPrime, in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
{
// The scanner always supplies matching spans, so the previous validation remains commented out.
// if (allowedMaxValues.Length < primes.Length)
@@ -165,7 +145,12 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
// divisorLimit = _divisorLimit;
// }
divisorLimit = _divisorLimit;
// EvenPerfectBitScanner configures the GPU tester once before scanning and never mutates the configuration afterwards,
// so synchronization and runtime configuration guards are unnecessary here.
divisorLimit = ComputeDivisorLimitFromMaxPrimeGpu(maxPrime);
_divisorLimit = divisorLimit;
for (int index = 0; index < primes.Length; index++)
{
@@ -526,12 +511,12 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
private readonly Accelerator _accelerator;
private readonly PrimeOrderCalculatorAccelerator _primeOrderCalculatorAccelerator;
private readonly AcceleratorStream _stream;
private Action<AcceleratorStream, Index1D, ArrayView<GpuDivisorPartialData>, ArrayView<int>, ArrayView<int>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<byte>, ArrayView<int>> _kernel = null!;
private MemoryBuffer1D<GpuDivisorPartialData, Stride1D.Dense> _divisorBuffer = null!;
private MemoryBuffer1D<int, Stride1D.Dense> _offsetBuffer = null!;
private MemoryBuffer1D<int, Stride1D.Dense> _countBuffer = null!;
private MemoryBuffer1D<ulong, Stride1D.Dense> _cycleBuffer = null!;
private MemoryBuffer1D<int, Stride1D.Dense> _firstHitBuffer = null!;
private readonly Action<AcceleratorStream, Index1D, ArrayView<GpuDivisorPartialData>, ArrayView<int>, ArrayView<int>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<byte>, ArrayView<int>> _kernel = null!;
private readonly MemoryBuffer1D<GpuDivisorPartialData, Stride1D.Dense> _divisorBuffer = null!;
private readonly MemoryBuffer1D<int, Stride1D.Dense> _offsetBuffer = null!;
private readonly MemoryBuffer1D<int, Stride1D.Dense> _countBuffer = null!;
private readonly MemoryBuffer1D<ulong, Stride1D.Dense> _cycleBuffer = null!;
private readonly MemoryBuffer1D<int, Stride1D.Dense> _firstHitBuffer = null!;
private MemoryBuffer1D<ulong, Stride1D.Dense> _exponentsBuffer = null!;
private MemoryBuffer1D<byte, Stride1D.Dense> _hitBuffer = null!;
private ulong[] _hostBuffer = null!;
@@ -546,7 +531,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
Accelerator accelerator = gpu.Accelerator;
_accelerator = accelerator;
_stream = accelerator.CreateStream();
_capacity = Math.Max(1, owner._gpuBatchSize);
// lock (accelerator)
{
@@ -559,11 +543,9 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
int desiredCapacity = PerfectNumberConstants.DefaultSmallPrimeFactorSlotCount;
_capacity = desiredCapacity;
// lock (accelerator)
{
_exponentsBuffer = accelerator.Allocate1D<ulong>(desiredCapacity);
_hitBuffer = accelerator.Allocate1D<byte>(desiredCapacity);
}
_exponentsBuffer = accelerator.Allocate1D<ulong>(desiredCapacity);
_hitBuffer = accelerator.Allocate1D<byte>(desiredCapacity);
_hostBuffer = ThreadStaticPools.UlongPool.Rent(desiredCapacity);
@@ -729,23 +711,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
public int GetHashCode(Accelerator obj) => RuntimeHelpers.GetHashCode(obj);
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public ulong GetAllowedMaxDivisor(ulong prime)
{
// The configuration is immutable after setup, so the cached limit can be read without locking.
// lock (_sync)
// {
// if (!_isConfigured)
// {
// throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
// }
// return ComputeAllowedMaxDivisorGpu(prime, _divisorLimit);
// }
return ComputeAllowedMaxDivisorGpu(prime, _divisorLimit);
}
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu)
{
@@ -7,7 +7,7 @@ public readonly struct SmallPrimeFactorGpuTables
{
private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
private static readonly SmallPrimeFactorGpuTables?[] _sharedTables = new SmallPrimeFactorGpuTables?[PerfectNumberConstants.RollingAccelerators];
private static readonly SmallPrimeFactorGpuTables?[] _sharedTables = new SmallPrimeFactorGpuTables?[EnvironmentConfiguration.RollingAccelerators];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static SmallPrimeFactorGpuTables? GetStaticTables(int acceleratorIndex) => _sharedTables[acceleratorIndex];
@@ -5,32 +5,20 @@ namespace PerfectNumbers.Core;
public interface IMersenneNumberDivisorByDivisorTester
{
int BatchSize { get; set; }
BigInteger MinK { get; set; }
void ConfigureFromMaxPrime(ulong maxPrime);
ulong DivisorLimit { get; }
ulong GetAllowedMaxDivisor(ulong prime);
bool IsPrime(PrimeOrderCalculatorAccelerator gpu, ulong prime, out bool divisorsExhausted, out BigInteger divisor);
bool IsPrime(ulong prime, out bool divisorsExhausted, out BigInteger divisor);
IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu);
string? StateFilePath { get; set; }
void ResetStateTracking();
void ResumeFromState(BigInteger lastSavedK);
void ResumeFromState(in string stateFile, in BigInteger lastSavedK, in BigInteger minK);
void PrepareCandidates(in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues);
void PrepareCandidates(ulong maxPrime, in ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues);
public interface IDivisorScanSession
{
bool CheckDivisor(ulong divisor, in MontgomeryDivisorData divisorData, ulong divisorCycle, in ReadOnlySpan<ulong> primes);
void Return();
// void Return();
}
}
File diff suppressed because it is too large. Load diff
@@ -12,14 +12,14 @@ public static class PerfectNumberConstants
public const int DefaultThreadPoolCapacity = 30_000;
public const int DefaultSpecialMaxFactorCapacity = 1024;
public const ulong ExtraDivisorCycleSearchLimit = 64UL;
public static int GpuRatio = 16384 - 1;
public const int GpuRatio = 16384 - 1;
public const int MaxQForDivisorCycles = 4_000_000;
public static readonly uint PrimesLimit = 1_000_000; //(ulong)Array.MaxLength;// 1_000_000;
public static readonly uint PrimesLimit = 1_000_000;
public const int DefaultStringBuilderCapacity = 10_240;
public const int MaxOddPowersCount = 128;
public const int PooledArrayThreshold = 64;
public const int Pow2WindowSize = 8;
public static int RollingAccelerators = 298; //SharedGpuContext.Device.MaxNumThreadsPerGroup;
public const int RollingAccelerators = 298;
public const int ThreadsByAccelerator = 1;
public const int ByDivisorStateSaveInterval = 200_000;
public const string ByDivisorStateDirectory = "Checks";
@@ -328,12 +328,13 @@ internal static partial class PrimeOrderCalculator
[MethodImpl(MethodImplOptions.AggressiveOptimization)]
private static bool RunOnCpu()
{
if (PerfectNumberConstants.GpuRatio == 0)
int gpuRatio = EnvironmentConfiguration.GpuRatio;
if (gpuRatio == 0)
{
return false;
}
if (PerfectNumberConstants.GpuRatio == 1)
if (gpuRatio == 1)
{
while (true)
{
@@ -352,16 +353,16 @@ internal static partial class PrimeOrderCalculator
}
int cpuCount = Interlocked.Increment(ref _cpuCount);
if (cpuCount == PerfectNumberConstants.GpuRatio)
if (cpuCount == gpuRatio)
{
Interlocked.Add(ref _cpuCount, -PerfectNumberConstants.GpuRatio);
Interlocked.Add(ref _cpuCount, -gpuRatio);
}
else if (cpuCount > PerfectNumberConstants.GpuRatio)
else if (cpuCount > gpuRatio)
{
cpuCount -= PerfectNumberConstants.GpuRatio;
cpuCount -= gpuRatio;
}
return cpuCount != PerfectNumberConstants.GpuRatio;
return cpuCount != gpuRatio;
}
[MethodImpl(MethodImplOptions.AggressiveOptimization)]
+2 -2
View File
@@ -153,9 +153,9 @@ internal sealed class TaskThreadPool
return false;
}
workItem = _pendingTaskQueue.Pop();
if (workItem is { })
if (_pendingTaskQueue.TryPop(out WorkItem dequeued))
{
workItem = dequeued;
Interlocked.Decrement(ref _pendingTaskCount);
return true;
}
+15 -15
View File
@@ -127,24 +127,24 @@ namespace PerfectNumbers.Core
get => _gpuUInt128Pool ??= ArrayPool<GpuUInt128>.Create();
}
[ThreadStatic]
private static MersenneCpuDivisorScanSession? _mersenneCpuDivisorSession;
// [ThreadStatic]
// private static MersenneCpuDivisorScanSession? _mersenneCpuDivisorSession;
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
internal static MersenneCpuDivisorScanSession RentMersenneCpuDivisorSession(Gpu.Accelerators.PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice)
{
if (_mersenneCpuDivisorSession is { } session)
{
session.Configure(gpu, orderDevice);
_mersenneCpuDivisorSession = null;
return session;
}
// [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
// internal static MersenneCpuDivisorScanSession RentMersenneCpuDivisorSession(Gpu.Accelerators.PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice)
// {
// if (_mersenneCpuDivisorSession is { } session)
// {
// session.Configure(gpu, orderDevice);
// _mersenneCpuDivisorSession = null;
// return session;
// }
return new MersenneCpuDivisorScanSession(gpu, orderDevice);
}
// return new MersenneCpuDivisorScanSession(gpu, orderDevice);
// }
[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
internal static void ReturnMersenneCpuDivisorSession(MersenneCpuDivisorScanSession session) => _mersenneCpuDivisorSession = session;
// [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
// internal static void ReturnMersenneCpuDivisorSession(MersenneCpuDivisorScanSession session) => _mersenneCpuDivisorSession = session;
[ThreadStatic]
private static ArrayPool<UInt128>? _uint128Pool;