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PrimeOrderCalculator.Cpu optimizations.

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mlemanczyk committed 2025-12-15 17:22:55 +01:00
1 parent 5523469e8a
commit 566cbc3599
4 files changed
+176 -75
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PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs
+7 -35
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@@ -545,12 +545,12 @@ internal static partial class PrimeOrderCalculator
private static ulong ExponentLoweringCpu(ulong order, ulong prime, PartialFactorResult factors, in MontgomeryDivisorData divisorData)
{
int length = factors.Count;
ReadOnlySpan<ulong> factorSpan = factors.Factors.AsSpan(0, length);
ReadOnlySpan<int> exponentsSpan = factors.Exponents.AsSpan(0, length);
ReadOnlySpan<ulong> factorSpan = new(factors.Factors, 0, length);
ReadOnlySpan<int> exponentsSpan = new(factors.Exponents, 0, length);
int newLength = length + 1;
ulong[] tempFactorsArray = FixedCapacityPools.ExclusiveUlongArray.Rent(newLength);
int[] tempExponentsArray = FixedCapacityPools.ExclusiveIntArray.Rent(newLength);
ulong[] tempFactorsArray = factors.TempFactorsArray;
int[] tempExponentsArray = factors.TempExponentsArray;
Span<ulong> ulongBuffer = tempFactorsArray;
factorSpan.CopyTo(ulongBuffer);
@@ -568,14 +568,8 @@ internal static partial class PrimeOrderCalculator
ExponentRemainderStepperCpu stepper = ThreadStaticPools.RentExponentStepperCpu(divisorData);
const int StackExponentCapacity = 16;
const int ExponentHardLimit = 256;
Span<ulong> stackCandidates = stackalloc ulong[StackExponentCapacity];
Span<bool> stackEvaluations = stackalloc bool[StackExponentCapacity];
ulong[]? heapCandidateArray = null;
bool[]? heapEvaluationArray = null;
Span<ulong> stackCandidates = new(factors.StackCandidates);
Span<bool> stackEvaluations = new(factors.StackEvaluations);
for (int i = 0; i < length; i++)
{
@@ -587,31 +581,10 @@ internal static partial class PrimeOrderCalculator
// continue;
// }
if (exponent > ExponentHardLimit)
{
throw new InvalidOperationException($"Prime factor exponent {exponent} exceeds the supported limit of {ExponentHardLimit}.");
}
if (exponent <= StackExponentCapacity)
{
ProcessExponentLoweringPrime(stackCandidates[..exponent], stackEvaluations[..exponent], ref order, primeFactor, exponent, ref stepper);
continue;
}
heapCandidateArray ??= FixedCapacityPools.ExclusiveUlongArray.Rent(ExponentHardLimit);
heapEvaluationArray ??= ThreadStaticPools.BoolPool.Rent(ExponentHardLimit);
ProcessExponentLoweringPrime(heapCandidateArray.AsSpan(0, exponent), heapEvaluationArray.AsSpan(0, exponent), ref order, primeFactor, exponent, ref stepper);
ProcessExponentLoweringPrime(stackCandidates[..exponent], stackEvaluations[..exponent], ref order, primeFactor, exponent, ref stepper);
}
ThreadStaticPools.ReturnExponentStepperCpu(stepper);
if (heapCandidateArray is not null)
{
FixedCapacityPools.ExclusiveUlongArray.Return(heapCandidateArray);
ThreadStaticPools.BoolPool.Return(heapEvaluationArray!);
}
FixedCapacityPools.ExclusiveUlongArray.Return(tempFactorsArray);
return order;
}
@@ -1945,4 +1918,3 @@ internal static partial class PrimeOrderCalculator
}