mlemanczyk/even-perfect-numbers-scanner
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Cache removed. It was barely every hit.

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mlemanczyk committed 2025-10-20 16:56:49 +02:00
1 parent c726d6de6b
commit 5d5fb28765
1 file changed
+10 -58
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PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs
+10 -58
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@@ -698,54 +698,6 @@ internal static partial class PrimeOrderCalculator
return exponent.Pow2MontgomeryModWindowedCpu(divisorData, keepMontgomery: false) == 1UL;
}
// [ThreadStatic]
private static readonly Dictionary<ulong, bool> _primalityCache = new(4_096);
private static readonly ReaderWriterLockSlim _primalityCacheLock = new(LockRecursionPolicy.NoRecursion);
// [ThreadStatic]
// private static UInt128 _isPrimeHits;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool TryGetCachedPrimality(ulong value, out bool isPrime)
{
if (value > (ulong)PerfectNumberConstants.MaxQForDivisorCycles)
{
isPrime = false;
return false;
}
_primalityCacheLock.EnterReadLock();
bool result = _primalityCache.TryGetValue(value, out isPrime);
_primalityCacheLock.ExitReadLock();
return result;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void CachePrimalityResult(ulong value, bool isPrime)
{
if (value > (ulong)PerfectNumberConstants.MaxQForDivisorCycles)
{
return;
}
_primalityCacheLock.EnterWriteLock();
_primalityCache[value] = isPrime;
_primalityCacheLock.ExitWriteLock();
}
private static bool GetOrComputePrimality(ulong value)
{
if (!TryGetCachedPrimality(value, out bool isPrime))
{
isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(value);
CachePrimalityResult(value, isPrime);
}
return isPrime;
}
private static PartialFactorResult PartialFactor(ulong value, in PrimeOrderSearchConfig config)
{
if (value <= 1UL)
@@ -846,7 +798,7 @@ internal static partial class PrimeOrderCalculator
// continue;
// }
bool isPrime = GetOrComputePrimality(composite);
bool isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(composite);
if (isPrime)
{
@@ -906,7 +858,7 @@ internal static partial class PrimeOrderCalculator
if (!entry.HasKnownPrimality)
{
bool isPrime = GetOrComputePrimality(composite);
bool isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(composite);
entry = entry.WithPrimality(isPrime);
pending[index] = entry;
}
@@ -935,7 +887,7 @@ internal static partial class PrimeOrderCalculator
}
else
{
cofactorIsPrime = GetOrComputePrimality(cofactor);
cofactorIsPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(cofactor);
}
ArrayPool<FactorEntry> pool = ThreadStaticPools.FactorEntryPool;
@@ -1462,7 +1414,8 @@ internal static partial class PrimeOrderCalculator
return;
}
if (!knownComposite && GetOrComputePrimality(value))
bool isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(value);
if (!knownComposite && isPrime)
{
AddFactor(counts, value, 1);
return;
@@ -1471,8 +1424,8 @@ internal static partial class PrimeOrderCalculator
ulong factor = PollardRhoStrict(value);
ulong quotient = value / factor;
bool factorIsPrime = GetOrComputePrimality(factor);
if (factorIsPrime)
isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(factor);
if (isPrime)
{
int exponent = 1;
ulong remaining = quotient;
@@ -1494,17 +1447,16 @@ internal static partial class PrimeOrderCalculator
FactorCompletely(factor, counts, knownComposite: true);
bool quotientIsPrime;
if (quotient == factor)
{
quotientIsPrime = false;
isPrime = false;
}
else
{
quotientIsPrime = GetOrComputePrimality(quotient);
isPrime = Open.Numeric.Primes.Prime.Numbers.IsPrime(quotient);
}
if (quotientIsPrime)
if (isPrime)
{
AddFactor(counts, quotient, 1);
}