922 lines
30 KiB
C#
922 lines
30 KiB
C#
using System;
|
|
using System.Buffers;
|
|
using System.Collections.Concurrent;
|
|
using System.Collections.Generic;
|
|
using System.Numerics;
|
|
using PerfectNumbers.Core;
|
|
using PerfectNumbers.Core.Gpu;
|
|
|
|
namespace PerfectNumbers.Core.Cpu;
|
|
|
|
public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDivisorByDivisorTester
|
|
{
|
|
private readonly object _sync = new();
|
|
private readonly ConcurrentBag<DivisorScanSession> _sessionPool = new();
|
|
private ulong _divisorLimit;
|
|
private ulong _lastStatusDivisor;
|
|
private bool _isConfigured;
|
|
private int _batchSize = 1_024;
|
|
|
|
private ulong _configuredMaxPrime;
|
|
private ByDivisorDeltasDevice _deltasDevice = ByDivisorDeltasDevice.Cpu;
|
|
|
|
|
|
public int BatchSize
|
|
{
|
|
get => _batchSize;
|
|
set
|
|
{
|
|
int sanitized = Math.Max(1, value);
|
|
_batchSize = sanitized;
|
|
}
|
|
}
|
|
|
|
public ByDivisorDeltasDevice DeltasDevice
|
|
{
|
|
get => _deltasDevice;
|
|
set
|
|
{
|
|
lock (_sync)
|
|
{
|
|
_deltasDevice = value;
|
|
}
|
|
}
|
|
}
|
|
|
|
public void ConfigureFromMaxPrime(ulong maxPrime)
|
|
{
|
|
lock (_sync)
|
|
{
|
|
_configuredMaxPrime = maxPrime;
|
|
_divisorLimit = ComputeDivisorLimitFromMaxPrime(maxPrime);
|
|
_lastStatusDivisor = 0UL;
|
|
_isConfigured = true;
|
|
}
|
|
}
|
|
|
|
public ulong DivisorLimit
|
|
{
|
|
get
|
|
{
|
|
lock (_sync)
|
|
{
|
|
if (!_isConfigured)
|
|
{
|
|
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
|
|
}
|
|
|
|
return _divisorLimit;
|
|
}
|
|
}
|
|
}
|
|
|
|
public ulong GetAllowedMaxDivisor(ulong prime)
|
|
{
|
|
lock (_sync)
|
|
{
|
|
if (!_isConfigured)
|
|
{
|
|
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
|
|
}
|
|
|
|
return ComputeAllowedMaxDivisor(prime, _divisorLimit);
|
|
}
|
|
}
|
|
|
|
public bool IsPrime(ulong prime, out bool divisorsExhausted, TimeSpan? timeLimit = null)
|
|
{
|
|
ulong allowedMax;
|
|
lock (_sync)
|
|
{
|
|
if (!_isConfigured)
|
|
{
|
|
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
|
|
}
|
|
|
|
allowedMax = ComputeAllowedMaxDivisor(prime, _divisorLimit);
|
|
}
|
|
|
|
if (allowedMax < 3UL)
|
|
{
|
|
divisorsExhausted = true;
|
|
return true;
|
|
}
|
|
|
|
ulong processedCount;
|
|
ulong lastProcessed;
|
|
bool processedAll;
|
|
|
|
bool composite = CheckDivisors(
|
|
prime,
|
|
allowedMax,
|
|
out lastProcessed,
|
|
out processedAll,
|
|
out processedCount,
|
|
timeLimit);
|
|
|
|
if (processedCount > 0UL)
|
|
{
|
|
lock (_sync)
|
|
{
|
|
UpdateStatusUnsafe(processedCount);
|
|
}
|
|
}
|
|
|
|
if (composite)
|
|
{
|
|
divisorsExhausted = true;
|
|
return false;
|
|
}
|
|
|
|
divisorsExhausted = processedAll || composite;
|
|
return true;
|
|
}
|
|
|
|
public void PrepareCandidates(ReadOnlySpan<ulong> primes, Span<ulong> allowedMaxValues)
|
|
{
|
|
if (allowedMaxValues.Length < primes.Length)
|
|
{
|
|
throw new ArgumentException("allowedMaxValues span must be at least as long as primes span.", nameof(allowedMaxValues));
|
|
}
|
|
|
|
ulong divisorLimit;
|
|
|
|
lock (_sync)
|
|
{
|
|
if (!_isConfigured)
|
|
{
|
|
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
|
|
}
|
|
|
|
divisorLimit = _divisorLimit;
|
|
}
|
|
|
|
for (int index = 0; index < primes.Length; index++)
|
|
{
|
|
allowedMaxValues[index] = ComputeAllowedMaxDivisor(primes[index], divisorLimit);
|
|
}
|
|
}
|
|
|
|
public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession()
|
|
{
|
|
lock (_sync)
|
|
{
|
|
if (!_isConfigured)
|
|
{
|
|
throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
|
|
}
|
|
|
|
if (_sessionPool.TryTake(out DivisorScanSession? session))
|
|
{
|
|
session.Reset();
|
|
return session;
|
|
}
|
|
|
|
return new DivisorScanSession(this);
|
|
}
|
|
}
|
|
|
|
private void ReturnSession(DivisorScanSession session)
|
|
{
|
|
_sessionPool.Add(session);
|
|
}
|
|
|
|
private bool CheckDivisors(
|
|
ulong prime,
|
|
ulong allowedMax,
|
|
out ulong lastProcessed,
|
|
out bool processedAll,
|
|
out ulong processedCount,
|
|
TimeSpan? timeLimit)
|
|
{
|
|
if (_deltasDevice == ByDivisorDeltasDevice.Cpu)
|
|
{
|
|
return CheckDivisorsCpu(prime, allowedMax, out lastProcessed, out processedAll, out processedCount, timeLimit);
|
|
}
|
|
|
|
return CheckDivisorsGpu(prime, allowedMax, out lastProcessed, out processedAll, out processedCount, timeLimit);
|
|
}
|
|
|
|
private bool CheckDivisorsCpu(
|
|
ulong prime,
|
|
ulong allowedMax,
|
|
out ulong lastProcessed,
|
|
out bool processedAll,
|
|
out ulong processedCount,
|
|
TimeSpan? timeLimit)
|
|
{
|
|
lastProcessed = 0UL;
|
|
processedCount = 0UL;
|
|
processedAll = false;
|
|
|
|
PrimeTestTimeLimit limitGuard;
|
|
if (!PrimeTestTimeLimit.TryCreate(timeLimit, out limitGuard))
|
|
{
|
|
return false;
|
|
}
|
|
|
|
bool enforceLimit = limitGuard.IsActive;
|
|
ulong iterationCounter = 0UL;
|
|
|
|
if (allowedMax < 3UL)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
UInt128 step = (UInt128)prime << 1;
|
|
if (step == UInt128.Zero)
|
|
{
|
|
processedAll = true;
|
|
return false;
|
|
}
|
|
|
|
UInt128 limit = allowedMax;
|
|
UInt128 divisor = step + UInt128.One;
|
|
if (divisor > limit)
|
|
{
|
|
processedAll = true;
|
|
return false;
|
|
}
|
|
|
|
Dictionary<ulong, MersenneDivisorCycles.FactorCacheEntry>? factorCache = null;
|
|
DivisorCycleCache cycleCache = DivisorCycleCache.Shared;
|
|
|
|
ulong cachedModulus = 0UL;
|
|
MontgomeryDivisorData cachedDivisorData = default;
|
|
bool hasCachedDivisorData = false;
|
|
|
|
byte step10 = (byte)(step % 10UL);
|
|
byte step8 = (byte)(step % 8UL);
|
|
byte step5 = (byte)(step % 5UL);
|
|
byte step3 = (byte)(step % 3UL);
|
|
byte step7 = (byte)(step % 7UL);
|
|
byte step11 = (byte)(step % 11UL);
|
|
|
|
byte remainder10 = (byte)(divisor % 10UL);
|
|
byte remainder8 = (byte)(divisor % 8UL);
|
|
byte remainder5 = (byte)(divisor % 5UL);
|
|
byte remainder3 = (byte)(divisor % 3UL);
|
|
byte remainder7 = (byte)(divisor % 7UL);
|
|
byte remainder11 = (byte)(divisor % 11UL);
|
|
|
|
// Keep the divisibility filters aligned with the divisor-cycle generator so the
|
|
// CPU path never requests cycles that were skipped during cache creation.
|
|
bool lastIsSeven = (prime & 3UL) == 3UL;
|
|
|
|
while (divisor <= limit)
|
|
{
|
|
if (enforceLimit && (iterationCounter == 0UL || (iterationCounter & 63UL) == 0UL) && limitGuard.HasExpired())
|
|
{
|
|
processedAll = false;
|
|
return false;
|
|
}
|
|
|
|
iterationCounter++;
|
|
ulong candidate = (ulong)divisor;
|
|
processedCount++;
|
|
lastProcessed = candidate;
|
|
|
|
bool admissible = lastIsSeven
|
|
? (remainder10 == 3 || remainder10 == 7 || remainder10 == 9)
|
|
: (remainder10 == 1 || remainder10 == 3 || remainder10 == 9);
|
|
|
|
if (admissible && (remainder8 == 1 || remainder8 == 7) && remainder3 != 0 && remainder5 != 0 && remainder7 != 0 && remainder11 != 0)
|
|
{
|
|
if (!hasCachedDivisorData || cachedModulus != candidate)
|
|
{
|
|
cachedDivisorData = MontgomeryDivisorData.FromModulus(candidate);
|
|
cachedModulus = candidate;
|
|
hasCachedDivisorData = true;
|
|
}
|
|
|
|
MontgomeryDivisorData divisorData = cachedDivisorData;
|
|
ulong divisorCycle;
|
|
|
|
if (candidate <= PerfectNumberConstants.MaxQForDivisorCycles)
|
|
{
|
|
divisorCycle = cycleCache.GetCycleLength(candidate);
|
|
}
|
|
else
|
|
{
|
|
factorCache ??= new Dictionary<ulong, MersenneDivisorCycles.FactorCacheEntry>(8);
|
|
// EvenPerfectBitScanner reaches this path only for divisors above the precomputed cycle snapshot.
|
|
// Those candidates follow q = 2 * prime * k + 1 with prime >= 5, so the downstream order calculator
|
|
// can rely on an odd divisor and a prime exponent when deriving the cycle length.
|
|
if (!MersenneDivisorCycles.TryCalculateCycleLengthForExponent(candidate, prime, divisorData, factorCache, out divisorCycle) || divisorCycle == 0UL)
|
|
{
|
|
divisorCycle = cycleCache.GetCycleLength(candidate);
|
|
}
|
|
}
|
|
|
|
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.
|
|
processedAll = true;
|
|
return true;
|
|
}
|
|
|
|
if (divisorCycle == 0UL)
|
|
{
|
|
Console.WriteLine($"Divisor cycle was not calculated for {prime}");
|
|
}
|
|
}
|
|
|
|
divisor += step;
|
|
remainder10 = AddMod(remainder10, step10, (byte)10);
|
|
remainder8 = AddMod(remainder8, step8, (byte)8);
|
|
remainder5 = AddMod(remainder5, step5, (byte)5);
|
|
remainder3 = AddMod(remainder3, step3, (byte)3);
|
|
remainder7 = AddMod(remainder7, step7, (byte)7);
|
|
remainder11 = AddMod(remainder11, step11, (byte)11);
|
|
}
|
|
|
|
processedAll = divisor > limit;
|
|
return false;
|
|
}
|
|
|
|
|
|
private bool CheckDivisorsGpu(
|
|
ulong prime,
|
|
ulong allowedMax,
|
|
out ulong lastProcessed,
|
|
out bool processedAll,
|
|
out ulong processedCount,
|
|
TimeSpan? timeLimit)
|
|
{
|
|
lastProcessed = 0UL;
|
|
processedCount = 0UL;
|
|
processedAll = false;
|
|
|
|
PrimeTestTimeLimit limitGuard;
|
|
if (!PrimeTestTimeLimit.TryCreate(timeLimit, out limitGuard))
|
|
{
|
|
return false;
|
|
}
|
|
|
|
bool enforceLimit = limitGuard.IsActive;
|
|
ulong iterationCounter = 0UL;
|
|
|
|
if (allowedMax < 3UL)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
UInt128 step = (UInt128)prime << 1;
|
|
if (step == UInt128.Zero)
|
|
{
|
|
processedAll = true;
|
|
return false;
|
|
}
|
|
|
|
UInt128 limit = allowedMax;
|
|
UInt128 divisor = step + UInt128.One;
|
|
if (divisor > limit)
|
|
{
|
|
processedAll = true;
|
|
return false;
|
|
}
|
|
|
|
int batchCapacity = Math.Max(1, _batchSize);
|
|
DivisorCycleCache cycleCache = DivisorCycleCache.Shared;
|
|
int preferredCycleBatch = cycleCache.PreferredBatchSize;
|
|
if (preferredCycleBatch > 0 && preferredCycleBatch < batchCapacity)
|
|
{
|
|
batchCapacity = preferredCycleBatch;
|
|
}
|
|
|
|
ulong[] candidateBuffer = ArrayPool<ulong>.Shared.Rent(batchCapacity);
|
|
ulong[] cycleBuffer = ArrayPool<ulong>.Shared.Rent(batchCapacity);
|
|
MontgomeryDivisorData[] divisorDataBuffer = ArrayPool<MontgomeryDivisorData>.Shared.Rent(batchCapacity);
|
|
byte[] remainderBuffer = ArrayPool<byte>.Shared.Rent(batchCapacity * 6);
|
|
|
|
Span<byte> remainder10Span = remainderBuffer.AsSpan(0, batchCapacity);
|
|
Span<byte> remainder8Span = remainderBuffer.AsSpan(batchCapacity, batchCapacity);
|
|
Span<byte> remainder5Span = remainderBuffer.AsSpan(batchCapacity * 2, batchCapacity);
|
|
Span<byte> remainder3Span = remainderBuffer.AsSpan(batchCapacity * 3, batchCapacity);
|
|
Span<byte> remainder7Span = remainderBuffer.AsSpan(batchCapacity * 4, batchCapacity);
|
|
Span<byte> remainder11Span = remainderBuffer.AsSpan(batchCapacity * 5, batchCapacity);
|
|
|
|
byte step10 = (byte)(step % 10UL);
|
|
byte step8 = (byte)(step % 8UL);
|
|
byte step5 = (byte)(step % 5UL);
|
|
byte step3 = (byte)(step % 3UL);
|
|
byte step7 = (byte)(step % 7UL);
|
|
byte step11 = (byte)(step % 11UL);
|
|
|
|
byte remainder10 = (byte)(divisor % 10UL);
|
|
byte remainder8 = (byte)(divisor % 8UL);
|
|
byte remainder5 = (byte)(divisor % 5UL);
|
|
byte remainder3 = (byte)(divisor % 3UL);
|
|
byte remainder7 = (byte)(divisor % 7UL);
|
|
byte remainder11 = (byte)(divisor % 11UL);
|
|
|
|
bool lastIsSeven = (prime & 3UL) == 3UL;
|
|
|
|
try
|
|
{
|
|
while (divisor <= limit)
|
|
{
|
|
Span<ulong> candidateSpan = candidateBuffer.AsSpan(0, batchCapacity);
|
|
int chunkCount = 0;
|
|
UInt128 localDivisor = divisor;
|
|
|
|
byte localRemainder10 = remainder10;
|
|
byte localRemainder8 = remainder8;
|
|
byte localRemainder5 = remainder5;
|
|
byte localRemainder3 = remainder3;
|
|
byte localRemainder7 = remainder7;
|
|
byte localRemainder11 = remainder11;
|
|
|
|
while (chunkCount < batchCapacity && localDivisor <= limit)
|
|
{
|
|
if (enforceLimit && (iterationCounter == 0UL || (iterationCounter & 63UL) == 0UL) && limitGuard.HasExpired())
|
|
{
|
|
processedAll = false;
|
|
return false;
|
|
}
|
|
|
|
ulong candidate = (ulong)localDivisor;
|
|
candidateSpan[chunkCount] = candidate;
|
|
remainder10Span[chunkCount] = localRemainder10;
|
|
remainder8Span[chunkCount] = localRemainder8;
|
|
remainder5Span[chunkCount] = localRemainder5;
|
|
remainder3Span[chunkCount] = localRemainder3;
|
|
remainder7Span[chunkCount] = localRemainder7;
|
|
remainder11Span[chunkCount] = localRemainder11;
|
|
|
|
processedCount++;
|
|
lastProcessed = candidate;
|
|
iterationCounter++;
|
|
chunkCount++;
|
|
|
|
localDivisor += step;
|
|
localRemainder10 = AddMod(localRemainder10, step10, (byte)10);
|
|
localRemainder8 = AddMod(localRemainder8, step8, (byte)8);
|
|
localRemainder5 = AddMod(localRemainder5, step5, (byte)5);
|
|
localRemainder3 = AddMod(localRemainder3, step3, (byte)3);
|
|
localRemainder7 = AddMod(localRemainder7, step7, (byte)7);
|
|
localRemainder11 = AddMod(localRemainder11, step11, (byte)11);
|
|
}
|
|
|
|
if (chunkCount == 0)
|
|
{
|
|
break;
|
|
}
|
|
|
|
divisor = localDivisor;
|
|
remainder10 = localRemainder10;
|
|
remainder8 = localRemainder8;
|
|
remainder5 = localRemainder5;
|
|
remainder3 = localRemainder3;
|
|
remainder7 = localRemainder7;
|
|
remainder11 = localRemainder11;
|
|
|
|
// Reuse the candidate buffer in-place so the filtered results stay contiguous without additional arrays.
|
|
Span<ulong> chunkCandidates = candidateSpan[..chunkCount];
|
|
int filteredCount = 0;
|
|
|
|
for (int i = 0; i < chunkCount; i++)
|
|
{
|
|
bool admissible = lastIsSeven
|
|
? (remainder10Span[i] == 3 || remainder10Span[i] == 7 || remainder10Span[i] == 9)
|
|
: (remainder10Span[i] == 1 || remainder10Span[i] == 3 || remainder10Span[i] == 9);
|
|
|
|
if (!admissible)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
if ((remainder8Span[i] != 1 && remainder8Span[i] != 7)
|
|
|| remainder3Span[i] == 0
|
|
|| remainder5Span[i] == 0
|
|
|| remainder7Span[i] == 0
|
|
|| remainder11Span[i] == 0)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
// Store the accepted candidate at the next free slot so the front of the span becomes the filtered set.
|
|
chunkCandidates[filteredCount++] = chunkCandidates[i];
|
|
}
|
|
|
|
if (filteredCount == 0)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
Span<ulong> filteredSpan = chunkCandidates[..filteredCount];
|
|
Span<ulong> cycleSpan = cycleBuffer.AsSpan(0, filteredCount);
|
|
cycleCache.GetCycleLengths(filteredSpan, cycleSpan);
|
|
|
|
int admissibleCount = 0;
|
|
Span<MontgomeryDivisorData> divisorDataSpan = divisorDataBuffer.AsSpan(0, filteredCount);
|
|
|
|
for (int i = 0; i < filteredCount; i++)
|
|
{
|
|
if (cycleSpan[i] != prime)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
ulong candidate = filteredSpan[i];
|
|
// Reuse the filtered span's leading segment to accumulate the admissible divisors for Montgomery checks.
|
|
filteredSpan[admissibleCount] = candidate;
|
|
divisorDataSpan[admissibleCount] = MontgomeryDivisorData.FromModulus(candidate);
|
|
admissibleCount++;
|
|
}
|
|
|
|
if (admissibleCount == 0)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
Span<ulong> admissibleSpan = filteredSpan[..admissibleCount];
|
|
Span<MontgomeryDivisorData> admissibleDataSpan = divisorDataSpan[..admissibleCount];
|
|
|
|
for (int i = 0; i < admissibleCount; i++)
|
|
{
|
|
if (CheckDivisor(prime, prime, in admissibleDataSpan[i]) != 0)
|
|
{
|
|
lastProcessed = admissibleSpan[i];
|
|
processedAll = true;
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
finally
|
|
{
|
|
ArrayPool<ulong>.Shared.Return(candidateBuffer, clearArray: false);
|
|
ArrayPool<ulong>.Shared.Return(cycleBuffer, clearArray: false);
|
|
ArrayPool<MontgomeryDivisorData>.Shared.Return(divisorDataBuffer, clearArray: false);
|
|
ArrayPool<byte>.Shared.Return(remainderBuffer, clearArray: false);
|
|
}
|
|
|
|
processedAll = divisor > limit;
|
|
return false;
|
|
}
|
|
private static byte CheckDivisor(ulong prime, ulong divisorCycle, in MontgomeryDivisorData divisorData)
|
|
{
|
|
ulong residue = prime.Pow2MontgomeryModWithCycleCpu(divisorCycle, divisorData);
|
|
return residue == 1UL ? (byte)1 : (byte)0;
|
|
}
|
|
|
|
private static byte AddMod(byte value, byte delta, byte modulus)
|
|
{
|
|
int sum = value + delta;
|
|
if (sum >= modulus)
|
|
{
|
|
sum -= modulus;
|
|
}
|
|
|
|
return (byte)sum;
|
|
}
|
|
|
|
private void UpdateStatusUnsafe(ulong processedCount)
|
|
{
|
|
if (processedCount == 0UL)
|
|
{
|
|
return;
|
|
}
|
|
|
|
ulong interval = PerfectNumberConstants.ConsoleInterval;
|
|
if (interval == 0UL)
|
|
{
|
|
_lastStatusDivisor = 0UL;
|
|
return;
|
|
}
|
|
|
|
ulong total = _lastStatusDivisor + processedCount;
|
|
// TODO: Replace this modulo with the ring-buffer style counter (subtract loop) used in the fast CLI
|
|
// status benchmarks so we avoid `%` in this hot loop while still wrapping progress correctly.
|
|
_lastStatusDivisor = total % interval;
|
|
}
|
|
|
|
private static ulong ComputeDivisorLimitFromMaxPrime(ulong maxPrime)
|
|
{
|
|
if (maxPrime <= 1UL)
|
|
{
|
|
return 0UL;
|
|
}
|
|
|
|
if (maxPrime - 1UL >= 64UL)
|
|
{
|
|
return ulong.MaxValue;
|
|
}
|
|
|
|
return (1UL << (int)(maxPrime - 1UL)) - 1UL;
|
|
}
|
|
|
|
private static ulong ComputeAllowedMaxDivisor(ulong prime, ulong divisorLimit)
|
|
{
|
|
if (prime <= 1UL)
|
|
{
|
|
return 0UL;
|
|
}
|
|
|
|
if (prime - 1UL >= 64UL)
|
|
{
|
|
return divisorLimit;
|
|
}
|
|
|
|
return Math.Min((1UL << (int)(prime - 1UL)) - 1UL, divisorLimit);
|
|
}
|
|
|
|
private sealed class DivisorScanSession : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
|
|
{
|
|
private readonly MersenneNumberDivisorByDivisorCpuTester _owner;
|
|
private bool _disposed;
|
|
private bool _hasCachedDivisorData;
|
|
private ulong _cachedDivisor;
|
|
private MontgomeryDivisorData _cachedDivisorData;
|
|
private ulong[]? _primeDeltas;
|
|
private ulong[]? _cycleRemainders;
|
|
private ulong[]? _montgomeryDeltas;
|
|
private int _bufferCapacity;
|
|
private MersenneNumberDivisorResidueGpuEvaluator? _gpuResidueEvaluator;
|
|
|
|
internal DivisorScanSession(MersenneNumberDivisorByDivisorCpuTester owner)
|
|
{
|
|
_owner = owner;
|
|
}
|
|
|
|
internal void Reset()
|
|
{
|
|
_disposed = false;
|
|
_hasCachedDivisorData = false;
|
|
_cachedDivisor = 0UL;
|
|
_cachedDivisorData = default;
|
|
}
|
|
|
|
public void CheckDivisor(ulong divisor, in MontgomeryDivisorData divisorData, ulong divisorCycle, ReadOnlySpan<ulong> primes, Span<byte> hits)
|
|
{
|
|
if (_disposed)
|
|
{
|
|
throw new ObjectDisposedException(nameof(DivisorScanSession));
|
|
}
|
|
|
|
int length = primes.Length;
|
|
if (length == 0)
|
|
{
|
|
return;
|
|
}
|
|
|
|
MontgomeryDivisorData cachedData = divisorData;
|
|
if (cachedData.Modulus != divisor)
|
|
{
|
|
if (!_hasCachedDivisorData || _cachedDivisor != divisor)
|
|
{
|
|
_cachedDivisorData = MontgomeryDivisorData.FromModulus(divisor);
|
|
_cachedDivisor = divisor;
|
|
_hasCachedDivisorData = true;
|
|
}
|
|
|
|
cachedData = _cachedDivisorData;
|
|
}
|
|
|
|
ulong modulus = cachedData.Modulus;
|
|
if (modulus <= 1UL || (modulus & 1UL) == 0UL)
|
|
{
|
|
hits.Clear();
|
|
return;
|
|
}
|
|
|
|
if (divisorCycle == 0UL)
|
|
{
|
|
divisorCycle = DivisorCycleCache.Shared.GetCycleLength(divisor);
|
|
if (divisorCycle == 0UL)
|
|
{
|
|
hits.Clear();
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (_owner._deltasDevice == ByDivisorDeltasDevice.Cpu)
|
|
{
|
|
CheckDivisorCpu(cachedData, divisorCycle, primes, hits);
|
|
return;
|
|
}
|
|
|
|
CheckDivisorGpu(cachedData, divisorCycle, primes, hits, length);
|
|
}
|
|
|
|
private static void CheckDivisorCpu(
|
|
in MontgomeryDivisorData divisorData,
|
|
ulong divisorCycle,
|
|
ReadOnlySpan<ulong> primes,
|
|
Span<byte> hits)
|
|
{
|
|
// 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 exponentStepper = new ExponentRemainderStepper(divisorData);
|
|
if (!exponentStepper.IsValidModulus)
|
|
{
|
|
hits.Clear();
|
|
return;
|
|
}
|
|
|
|
var cycleStepper = new CycleRemainderStepper(divisorCycle);
|
|
|
|
ulong remainder = cycleStepper.Initialize(primes[0]);
|
|
hits[0] = remainder == 0UL
|
|
? (exponentStepper.ComputeNextIsUnity(primes[0]) ? (byte)1 : (byte)0)
|
|
: (byte)0;
|
|
|
|
int length = primes.Length;
|
|
for (int i = 1; i < length; i++)
|
|
{
|
|
remainder = cycleStepper.ComputeNext(primes[i]);
|
|
if (remainder != 0UL)
|
|
{
|
|
hits[i] = 0;
|
|
continue;
|
|
}
|
|
|
|
hits[i] = exponentStepper.ComputeNextIsUnity(primes[i]) ? (byte)1 : (byte)0;
|
|
}
|
|
}
|
|
|
|
private void CheckDivisorGpu(
|
|
in MontgomeryDivisorData divisorData,
|
|
ulong divisorCycle,
|
|
ReadOnlySpan<ulong> primes,
|
|
Span<byte> hits,
|
|
int length)
|
|
{
|
|
EnsureCapacity(length);
|
|
|
|
Span<ulong> deltaSpan = _primeDeltas!.AsSpan(0, length);
|
|
ComputePrimeDeltas(primes, deltaSpan);
|
|
|
|
Span<ulong> remainderSpan = _cycleRemainders!.AsSpan(0, length);
|
|
ComputeCycleRemainders(divisorCycle, primes, deltaSpan, remainderSpan);
|
|
|
|
EnsureGpuEvaluator();
|
|
Span<ulong> residueSpan = _montgomeryDeltas!.AsSpan(0, length);
|
|
_gpuResidueEvaluator!.ComputeResidues(primes, divisorData, residueSpan);
|
|
|
|
ulong montgomeryOne = divisorData.MontgomeryOne;
|
|
for (int i = 0; i < length; i++)
|
|
{
|
|
hits[i] = remainderSpan[i] == 0UL && residueSpan[i] == montgomeryOne ? (byte)1 : (byte)0;
|
|
}
|
|
}
|
|
|
|
private void EnsureGpuEvaluator()
|
|
{
|
|
if (_gpuResidueEvaluator is null)
|
|
{
|
|
_gpuResidueEvaluator = new MersenneNumberDivisorResidueGpuEvaluator(_owner._batchSize);
|
|
}
|
|
}
|
|
|
|
private void ReleaseGpuEvaluator()
|
|
{
|
|
if (_gpuResidueEvaluator is null)
|
|
{
|
|
return;
|
|
}
|
|
|
|
_gpuResidueEvaluator.Dispose();
|
|
_gpuResidueEvaluator = null;
|
|
}
|
|
|
|
private void EnsureCapacity(int requiredLength)
|
|
{
|
|
if (requiredLength <= 0)
|
|
{
|
|
return;
|
|
}
|
|
|
|
if (requiredLength <= _bufferCapacity && _primeDeltas is not null && _cycleRemainders is not null && _montgomeryDeltas is not null)
|
|
{
|
|
return;
|
|
}
|
|
|
|
int newCapacity = _bufferCapacity;
|
|
if (newCapacity == 0)
|
|
{
|
|
newCapacity = 1;
|
|
}
|
|
|
|
while (newCapacity < requiredLength)
|
|
{
|
|
newCapacity <<= 1;
|
|
}
|
|
|
|
ReturnBuffers();
|
|
|
|
_primeDeltas = ArrayPool<ulong>.Shared.Rent(newCapacity);
|
|
_cycleRemainders = ArrayPool<ulong>.Shared.Rent(newCapacity);
|
|
_montgomeryDeltas = ArrayPool<ulong>.Shared.Rent(newCapacity);
|
|
_bufferCapacity = newCapacity;
|
|
}
|
|
|
|
private void ReturnBuffers()
|
|
{
|
|
if (_primeDeltas is not null)
|
|
{
|
|
ArrayPool<ulong>.Shared.Return(_primeDeltas, clearArray: false);
|
|
_primeDeltas = null;
|
|
}
|
|
|
|
if (_cycleRemainders is not null)
|
|
{
|
|
ArrayPool<ulong>.Shared.Return(_cycleRemainders, clearArray: false);
|
|
_cycleRemainders = null;
|
|
}
|
|
|
|
if (_montgomeryDeltas is not null)
|
|
{
|
|
ArrayPool<ulong>.Shared.Return(_montgomeryDeltas, clearArray: false);
|
|
_montgomeryDeltas = null;
|
|
}
|
|
|
|
_bufferCapacity = 0;
|
|
}
|
|
|
|
private static void ComputePrimeDeltas(ReadOnlySpan<ulong> primes, Span<ulong> deltas)
|
|
{
|
|
if (primes.Length == 0)
|
|
{
|
|
return;
|
|
}
|
|
|
|
ulong previous = primes[0];
|
|
deltas[0] = previous;
|
|
|
|
for (int i = 1; i < primes.Length; i++)
|
|
{
|
|
ulong current = primes[i];
|
|
if (current <= previous)
|
|
{
|
|
throw new ArgumentOutOfRangeException(nameof(primes), "Primes must be strictly increasing.");
|
|
}
|
|
|
|
deltas[i] = current - previous;
|
|
previous = current;
|
|
}
|
|
}
|
|
|
|
private static void ComputeCycleRemainders(ulong cycleLength, ReadOnlySpan<ulong> primes, ReadOnlySpan<ulong> deltas, Span<ulong> remainders)
|
|
{
|
|
if (cycleLength == 0UL || primes.Length == 0)
|
|
{
|
|
remainders.Clear();
|
|
return;
|
|
}
|
|
|
|
ulong remainder = primes[0] % cycleLength;
|
|
remainders[0] = remainder;
|
|
|
|
for (int i = 1; i < primes.Length; i++)
|
|
{
|
|
remainder = AddMod(remainder, deltas[i], cycleLength);
|
|
remainders[i] = remainder;
|
|
}
|
|
}
|
|
|
|
private static ulong AddMod(ulong value, ulong delta, ulong modulus)
|
|
{
|
|
if (modulus == 0UL)
|
|
{
|
|
return 0UL;
|
|
}
|
|
|
|
if (ulong.MaxValue - value < delta)
|
|
{
|
|
UInt128 extended = (UInt128)value + delta;
|
|
return (ulong)(extended % modulus);
|
|
}
|
|
|
|
ulong sum = value + delta;
|
|
if (sum >= modulus)
|
|
{
|
|
sum -= modulus;
|
|
if (sum >= modulus)
|
|
{
|
|
sum %= modulus;
|
|
}
|
|
}
|
|
|
|
return sum;
|
|
}
|
|
|
|
public void Dispose()
|
|
{
|
|
if (_disposed)
|
|
{
|
|
return;
|
|
}
|
|
|
|
_disposed = true;
|
|
ReleaseGpuEvaluator();
|
|
_owner.ReturnSession(this);
|
|
}
|
|
}
|
|
}
|
|
|
|
|