mlemanczyk/even-perfect-numbers-scanner
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MontgomeryDivisorData converted to a pooled class to limit GC pressure. MontgomeryDivisorDataGpu added for GPU operations. PrimeOrderCalculator kernels precompiled during warmup.

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mlemanczyk committed 2025-11-24 15:14:31 +01:00
1 parent 07efd5d2a1
commit 070e2a14fd
32 files changed
+310 -192
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PerfectNumbers.Core/Cpu/MersenneCpuDivisorScanSession.cs
+4 -4
View File
@@ -21,10 +21,10 @@ internal sealed class MersenneCpuDivisorScanSession : IMersenneNumberDivisorByDi
// return;
// }
MontgomeryDivisorData cachedData = divisorData;
if (cachedData.Modulus != divisor)
if (divisorData.Modulus != divisor)
{
cachedData = MontgomeryDivisorData.FromModulus(divisor);
throw new InvalidOperationException("Divisor data is for a different modulus");
// cachedData = MontgomeryDivisorData.FromModulus(divisor);
}
if (divisorCycle == 0UL)
@@ -39,7 +39,7 @@ internal sealed class MersenneCpuDivisorScanSession : IMersenneNumberDivisorByDi
// 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 ExponentRemainderStepperCpu(cachedData);
var exponentStepper = new ExponentRemainderStepperCpu(divisorData);
var cycleStepper = new CycleRemainderStepper(divisorCycle);
PerfectNumbers.Core/Cpu/MersenneNumberDivisorByDivisorCpuTester.cs
+26 -32
View File
@@ -204,43 +204,37 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
remainder11 = (byte)((((divisorHigh % 11UL) * 5UL) + (divisorLow % 11UL)) % 11UL);
var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
var divisorPool = MontgomeryDivisorDataPool.Shared;
while (divisor.CompareTo(limit) <= 0)
{
bool passesSmallModuli = remainder3 != 0 && remainder7 != 0 && remainder11 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
ulong candidate = divisor.Low;
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(candidate);
MontgomeryDivisorData divisorData = divisorPool.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 (candidate <= PerfectNumberConstants.MaxQForDivisorCycles)
// {
// divisorCycle = cycleCache.GetCycleLength(candidate);
// }
// else
if (!MersenneDivisorCycles.TryCalculateCycleLengthForExponentCpu(
gpu,
candidate,
prime,
divisorData,
out ulong computedCycle,
out bool primeOrderFailed) || computedCycle == 0UL)
{
if (!MersenneDivisorCycles.TryCalculateCycleLengthForExponentCpu(
gpu,
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 = MersenneDivisorCycles.CalculateCycleLength(
candidate,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
// 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 = MersenneDivisorCycles.CalculateCycleLength(
candidate,
divisorData,
skipPrimeOrderHeuristic: primeOrderFailed);
}
else
{
divisorCycle = computedCycle;
}
divisorPool.Return(divisorData);
if (divisorCycle == prime)
{
// A cycle equal to the tested exponent (which is prime in this path) guarantees that the candidate divides
@@ -290,18 +284,16 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
out bool processedAll,
out ulong foundDivisor)
{
processedAll = false;
foundDivisor = 0UL;
bool canAdvance = step <= limit;
var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
Queue<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
if (!canAdvance)
{
if (divisor <= limit)
{
if (remainder3 != 0 && remainder7 != 0 && remainder11 != 0 && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneDivisorCycles.TryCalculateCycleLengthForExponentCpu(
gpu,
@@ -321,6 +313,8 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
divisorCycle = computedCycle;
}
divisorPool.Return(divisorData);
if (divisorCycle == prime)
{
foundDivisor = divisor;
@@ -351,13 +345,12 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
}
ulong remainingIterations = ((limit - divisor) / step) + 1UL;
while (true)
{
bool passesSmallModuli = remainder3 != 0 && remainder7 != 0 && remainder11 != 0;
if (passesSmallModuli && (remainder8 == 1 || remainder8 == 7) && ((decimalMask >> remainder10) & 1) != 0)
{
MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
ulong divisorCycle;
if (!MersenneDivisorCycles.TryCalculateCycleLengthForExponentCpu(
gpu,
@@ -377,6 +370,7 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
divisorCycle = computedCycle;
}
divisorPool.Return(divisorData);
if (divisorCycle == prime)
{
foundDivisor = divisor;