MontgomeryDivisorDataPool.Rent / .Return removed as we no longer pool Montgomery divisor data. UInt128Extensions.MontgomeryDivisorDataPool variables optimized.

EvenPerfectBitScanner.Benchmarks/Pow2ModBenchmarks.cs

@@ -500,7 +500,7 @@ public class Pow2ModBenchmarks
 				Console.WriteLine($"Calculating small cycle {smallModulus}");
 				smallDivisors[i] = CreateMontgomeryDivisorData(smallModulus);
 				smallExponents[i] = NextSmallExponent(random);
-				smallCycles[i] = MersenneDivisorCycles.CalculateCycleLengthCpu(smallModulus, MontgomeryDivisorDataPool.Shared.FromModulus(smallModulus));
+				smallCycles[i] = MersenneDivisorCycles.CalculateCycleLengthCpu(smallModulus, MontgomeryDivisorData.FromModulus(smallModulus));
 
 				(ulong largeModulus, ulong largeCycle) = NextLargeModulusAndCycle(random);
 				Console.WriteLine($"Calculating large cycle {largeModulus}");
@@ -613,7 +613,7 @@ public class Pow2ModBenchmarks
 
 		private static ulong CalculateCycleLengthWithHeuristicsCpu(ulong modulus, ref ulong? previousPrimeOrder)
 		{
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(modulus);
 			if (modulus <= 1UL || (modulus & 1UL) == 0UL)
 			{
 				return MersenneDivisorCycles.CalculateCycleLengthCpu(modulus, divisorData);
@@ -680,7 +680,7 @@ public class Pow2ModBenchmarks
 
 	private ulong CalculateCycleLengthWithHeuristicsCpu(ulong modulus, ulong fallbackOrder = 0UL)
 	{
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(modulus);
 		if (modulus <= 1UL || (modulus & 1UL) == 0UL)
 		{
 			return fallbackOrder != 0UL ? fallbackOrder : MersenneDivisorCycles.CalculateCycleLengthCpu(modulus, divisorData);
@@ -709,7 +709,7 @@ public class Pow2ModBenchmarks
 
 	private ulong CalculateCycleLengthWithHeuristicsGpu(PrimeOrderCalculatorAccelerator gpu, ulong modulus, ulong fallbackOrder = 0UL)
 	{
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(modulus);
 		if (modulus <= 1UL || (modulus & 1UL) == 0UL)
 		{
 			return fallbackOrder != 0UL ? fallbackOrder : MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, modulus, divisorData);

EvenPerfectBitScanner.Benchmarks/Pow2MontgomeryModBenchmarks.cs

@@ -39,7 +39,7 @@ public class Pow2MontgomeryModBenchmarks
 			ulong smallModulus = NextSmallOddModulus();
 			_smallDivisors[i] = CreateMontgomeryDivisorData(smallModulus);
 			_smallExponents[i] = NextSmallExponent();
-			_smallCycles[i] = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, smallModulus, MontgomeryDivisorDataPool.Shared.FromModulus(smallModulus));
+			_smallCycles[i] = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, smallModulus, MontgomeryDivisorData.FromModulus(smallModulus));
 
 			Console.WriteLine($"Calculating large cycle {i + 1} with heuristics");
 			(ulong largeModulus, ulong largeCycle) = NextLargeModulusAndCycle();

EvenPerfectBitScanner.Benchmarks/Pow2MontgomeryModWindowedBenchmarkData.cs

@@ -66,7 +66,7 @@ internal static class Pow2MontgomeryModWindowedBenchmarkInputsProvider
         {
             Pow2MontgomeryModWindowedBenchmarkSeed seed = seeds[i];
             ulong modulus = 2UL * seed.Multiplier * seed.Exponent + 1UL;
-            MontgomeryDivisorData divisor = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+            MontgomeryDivisorData divisor = MontgomeryDivisorData.FromModulus(modulus);
             ulong cycleLength = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, modulus, divisor);
             ulong reducedExponent = seed.Exponent % cycleLength;
             cases[i] = new Pow2MontgomeryModWindowedBenchmarkCase(

PerfectNumbers.Core.Tests/Gpu/PrimeOrderGpuHeuristicsTests.cs

@@ -5,7 +5,7 @@ using PerfectNumbers.Core.Gpu;
 using PerfectNumbers.Core.Gpu.Accelerators;
 using Xunit;
 
-namespace PerfectNumbers.Core.Tests;
+namespace PerfectNumbers.Core.Tests.Gpu;
 
 [Trait("Category", "Fast")]
 public class PrimeOrderGpuHeuristicsTests
@@ -25,7 +25,7 @@ public class PrimeOrderGpuHeuristicsTests
 		try
 		{
 			PrimeOrderGpuHeuristics.OverflowRegistry[prime] = 0;
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2Mod(gpu, 1UL, prime, out ulong remainder, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -43,7 +43,7 @@ public class PrimeOrderGpuHeuristicsTests
 	{
 		const ulong exponent = 138_000_001UL;
 		const ulong prime = 138_000_001UL;
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 		var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 		GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2Mod(gpu, exponent, prime, out ulong remainder, divisorData);
 
@@ -62,7 +62,7 @@ public class PrimeOrderGpuHeuristicsTests
 		var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 		try
 		{
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2Mod(gpu, 1UL, prime, out ulong remainder, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -85,7 +85,7 @@ public class PrimeOrderGpuHeuristicsTests
 		try
 		{
 			const ulong prime = 193UL;
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2Mod(gpu, 16UL, prime, out ulong remainder, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -113,7 +113,7 @@ public class PrimeOrderGpuHeuristicsTests
 
 			ulong[] remainders = new ulong[2];
 			ulong[] exponents = { 1UL, 2UL };
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2ModBatch(gpu, exponents, prime, remainders, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -133,7 +133,7 @@ public class PrimeOrderGpuHeuristicsTests
 		ulong[] remainders = { 123UL, 456UL };
 		ulong[] exponents = { 138_000_001UL, 138_000_011UL };
 		const ulong prime = 138_000_001UL;
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 
 		var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 		GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2ModBatch(gpu, exponents, prime, remainders, divisorData);
@@ -162,7 +162,7 @@ public class PrimeOrderGpuHeuristicsTests
 			ulong[] exponents = { 1UL, 2UL };
 			ulong[] remainders = { 5UL, 6UL };
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2ModBatch(gpu, exponents, prime, remainders, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -189,7 +189,7 @@ public class PrimeOrderGpuHeuristicsTests
 			ulong[] remainders = { 9UL, 11UL };
 
 			const ulong prime = 193UL;
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			GpuPow2ModStatus status = PrimeOrderGpuHeuristics.TryPow2ModBatch(gpu, exponents, prime, remainders, divisorData);
 
 			status.Should().Be(GpuPow2ModStatus.Overflow);
@@ -397,7 +397,7 @@ public class PrimeOrderGpuHeuristicsTests
 		{
 			PrimeOrderGpuHeuristics.OverflowRegistry[prime] = 0;
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(prime);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime);
 			ulong result = PrimeOrderCalculator.CalculateGpu(gpu, prime, null, divisorData, PrimeOrderCalculator.PrimeOrderCalculatorConfig.HeuristicDefault);
 
 			result.Should().Be(3UL);

PerfectNumbers.Core.Tests/Gpu/ULongExtensionsGpuTests.cs

@@ -18,7 +18,7 @@ public class ULongExtensionsGpuTests
     [InlineData(65535UL, 2147483647UL)]
     public void Pow2ModWindowedGpu_matches_montgomery_cpu_for_known_values(ulong exponent, ulong modulus)
     {
-        MontgomeryDivisorData divisor = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+        MontgomeryDivisorData divisor = MontgomeryDivisorData.FromModulus(modulus);
         ulong expected = exponent.Pow2MontgomeryModWindowedConvertToStandardCpu(divisor);
 
         exponent.Pow2ModWindowedGpu(modulus).Should().Be(expected);
@@ -52,7 +52,7 @@ public class ULongExtensionsGpuTests
 
         foreach (ulong modulus in moduli)
         {
-            MontgomeryDivisorData divisor = MontgomeryDivisorDataPool.Shared.FromModulus(modulus);
+            MontgomeryDivisorData divisor = MontgomeryDivisorData.FromModulus(modulus);
             foreach (ulong exponent in exponents)
             {
                 ulong expected = exponent.Pow2MontgomeryModWindowedConvertToStandardCpu(divisor);

PerfectNumbers.Core.Tests/MersenneDivisorCyclesGenerateGpuTests.cs

@@ -40,7 +40,7 @@ public class MersenneDivisorCyclesGenerateGpuTests
 			foreach (var pair in pairs)
 			{
 				expected.Should().Contain(pair.divisor);
-				MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(pair.divisor);
+				MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(pair.divisor);
 				pair.cycle.Should().Be(MersenneDivisorCycles.CalculateCycleLengthCpu(pair.divisor, divisorData));
 			}
 		}
@@ -90,7 +90,7 @@ public class MersenneDivisorCyclesGenerateGpuTests
 			foreach (var pair in pairs)
 			{
 				uniqueDivisors.Add(pair.divisor).Should().BeTrue();
-				MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(pair.divisor);
+				MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(pair.divisor);
 				pair.cycle.Should().Be(MersenneDivisorCycles.CalculateCycleLengthCpu(pair.divisor, divisorData));
 			}
 

PerfectNumbers.Core.Tests/MersenneDivisorCyclesTests.cs

@@ -22,7 +22,7 @@ public class MersenneDivisorCyclesTests
 		var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 		try
 		{
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(divisor);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 			MersenneDivisorCycles.CalculateCycleLengthCpu(divisor, divisorData).Should().Be(expected);
 			MersenneDivisorCycles.CalculateCycleLengthGpu(divisor).Should().Be(expected);
 		}

PerfectNumbers.Core.Tests/MersenneNumberDivisorCpuTesterTests.cs

@@ -49,17 +49,17 @@ public class MersenneNumberDivisorCpuTesterTests
 		{
 			ulong[] primes = [5UL, 7UL, 11UL, 13UL];
 
-			ulong cycle23 = MersenneDivisorCycles.CalculateCycleLengthCpu(23UL, MontgomeryDivisorDataPool.Shared.FromModulus(23UL));
+			ulong cycle23 = MersenneDivisorCycles.CalculateCycleLengthCpu(23UL, MontgomeryDivisorData.FromModulus(23UL));
-			session.CheckDivisor(23UL, MontgomeryDivisorDataPool.Shared.FromModulus(23UL), cycle23, primes).Should().BeTrue();
+			session.CheckDivisor(23UL, MontgomeryDivisorData.FromModulus(23UL), cycle23, primes).Should().BeTrue();
 
 			ulong[] primesWithoutHit = [5UL, 7UL, 13UL];
-			session.CheckDivisor(23UL, MontgomeryDivisorDataPool.Shared.FromModulus(23UL), cycle23, primesWithoutHit).Should().BeFalse();
+			session.CheckDivisor(23UL, MontgomeryDivisorData.FromModulus(23UL), cycle23, primesWithoutHit).Should().BeFalse();
 
-			ulong cycle31 = MersenneDivisorCycles.CalculateCycleLengthCpu(31UL, MontgomeryDivisorDataPool.Shared.FromModulus(31UL));
+			ulong cycle31 = MersenneDivisorCycles.CalculateCycleLengthCpu(31UL, MontgomeryDivisorData.FromModulus(31UL));
-			session.CheckDivisor(31UL, MontgomeryDivisorDataPool.Shared.FromModulus(31UL), cycle31, primes).Should().BeTrue();
+			session.CheckDivisor(31UL, MontgomeryDivisorData.FromModulus(31UL), cycle31, primes).Should().BeTrue();
 
 			ulong[] primesBeforeHit = [7UL, 11UL, 13UL];
-			session.CheckDivisor(31UL, MontgomeryDivisorDataPool.Shared.FromModulus(31UL), cycle31, primesBeforeHit).Should().BeFalse();
+			session.CheckDivisor(31UL, MontgomeryDivisorData.FromModulus(31UL), cycle31, primesBeforeHit).Should().BeFalse();
 		}
 		finally
 		{
@@ -81,7 +81,7 @@ public class MersenneNumberDivisorCpuTesterTests
 		{
 			ulong[] exponents = [6UL, 7UL, 9UL, 10UL, 12UL];
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(7UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(7UL);
 			ulong cycle = MersenneDivisorCycles.CalculateCycleLengthCpu(7UL, divisorData);
 			session.CheckDivisor(7UL, divisorData, cycle, exponents).Should().BeTrue();
 
@@ -108,7 +108,7 @@ public class MersenneNumberDivisorCpuTesterTests
 		{
 			ulong[] exponents = [10UL, 11UL, 20UL, 21UL, 30UL];
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(11UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(11UL);
 			ulong cycle = MersenneDivisorCycles.CalculateCycleLengthCpu(11UL, divisorData);
 			session.CheckDivisor(11UL, divisorData, cycle, exponents).Should().BeTrue();
 

PerfectNumbers.Core.Tests/MersenneNumberDivisorGpuTesterTests.cs

@@ -231,10 +231,10 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] primes = [31UL, 37UL, 41UL];
 
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), 0UL, primes).Should().BeTrue();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), 0UL, primes).Should().BeTrue();
 
 			ulong[] primesWithoutHit = [31UL, 41UL];
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), 0UL, primesWithoutHit).Should().BeFalse();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), 0UL, primesWithoutHit).Should().BeFalse();
 		}
 		finally
 		{
@@ -256,17 +256,17 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] primes = [31UL, 37UL, 41UL, 43UL];
 
-			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL));
+			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorData.FromModulus(223UL));
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primes).Should().BeTrue();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primes).Should().BeTrue();
 
 			ulong[] primesBeforeHit = [31UL];
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
 
-			ulong cycle13367 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 13367UL, MontgomeryDivisorDataPool.Shared.FromModulus(13367UL));
+			ulong cycle13367 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 13367UL, MontgomeryDivisorData.FromModulus(13367UL));
-			session.CheckDivisor(13367UL, MontgomeryDivisorDataPool.Shared.FromModulus(13367UL), cycle13367, primes).Should().BeTrue();
+			session.CheckDivisor(13367UL, MontgomeryDivisorData.FromModulus(13367UL), cycle13367, primes).Should().BeTrue();
 
 			ulong[] primesWithoutMatchingExponent = [31UL, 37UL, 43UL];
-			session.CheckDivisor(13367UL, MontgomeryDivisorDataPool.Shared.FromModulus(13367UL), cycle13367, primesWithoutMatchingExponent).Should().BeFalse();
+			session.CheckDivisor(13367UL, MontgomeryDivisorData.FromModulus(13367UL), cycle13367, primesWithoutMatchingExponent).Should().BeFalse();
 		}
 		finally
 		{
@@ -292,11 +292,11 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] primes = [31UL, 37UL, 41UL, 43UL, 47UL];
 
-			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL));
+			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorData.FromModulus(223UL));
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primes).Should().BeTrue();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primes).Should().BeTrue();
 
 			ulong[] primesBeforeHit = [31UL];
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
 		}
 		finally
 		{
@@ -321,7 +321,7 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] exponents = [6UL, 7UL, 9UL, 10UL, 12UL];
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(7UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(7UL);
 			ulong cycle = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 7UL, divisorData);
 
 			session.CheckDivisor(7UL, divisorData, cycle, exponents).Should().BeTrue();
@@ -352,7 +352,7 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] exponents = [10UL, 11UL, 20UL, 21UL, 30UL];
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(11UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(11UL);
 			ulong cycle = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 11UL, divisorData);
 
 			session.CheckDivisor(11UL, divisorData, cycle, exponents).Should().BeTrue();
@@ -384,7 +384,7 @@ public class MersenneNumberDivisorGpuTesterTests
 			var patchedTable = new List<(ulong Divisor, ulong Cycle)>();
 			ulong[] patchedSmall = new ulong[PerfectNumberConstants.MaxQForDivisorCycles + 1];
 
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(191UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(191UL);
 			patchedSmall[191] = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 191UL, divisorData);
 
 			tableField.SetValue(cycles, patchedTable);
@@ -428,11 +428,11 @@ public class MersenneNumberDivisorGpuTesterTests
 		{
 			ulong[] primes = [31UL, 37UL, 41UL, 43UL, 47UL];
 
-			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL));
+			ulong cycle223 = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, 223UL, MontgomeryDivisorData.FromModulus(223UL));
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primes).Should().BeTrue();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primes).Should().BeTrue();
 
 			ulong[] primesBeforeHit = [31UL];
-			session.CheckDivisor(223UL, MontgomeryDivisorDataPool.Shared.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
+			session.CheckDivisor(223UL, MontgomeryDivisorData.FromModulus(223UL), cycle223, primesBeforeHit).Should().BeFalse();
 		}
 		finally
 		{

PerfectNumbers.Core.Tests/PrimeOrderCalculatorTests.cs

@@ -49,7 +49,7 @@ public class PrimeOrderCalculatorTests
 			gpu,
 			prime,
 			previousOrder: null,
-			MontgomeryDivisorDataPool.Shared.FromModulus(prime),
+			MontgomeryDivisorData.FromModulus(prime),
 			PrimeOrderCalculator.PrimeOrderCalculatorConfig.HeuristicDefault);
 
 		PrimeOrderCalculatorAccelerator.Return(gpu);
@@ -69,14 +69,14 @@ public class PrimeOrderCalculatorTests
 			gpu,
 			prime,
 			previousOrder,
-			MontgomeryDivisorDataPool.Shared.FromModulus(prime),
+			MontgomeryDivisorData.FromModulus(prime),
 			PrimeOrderCalculator.PrimeOrderCalculatorConfig.HeuristicDefault);
 
 		ulong strict = PrimeOrderCalculator.CalculateGpu(
 			gpu,
 			prime,
 			previousOrder: null,
-			MontgomeryDivisorDataPool.Shared.FromModulus(prime),
+			MontgomeryDivisorData.FromModulus(prime),
 			PrimeOrderCalculator.PrimeOrderCalculatorConfig.StrictDefault);
 
 		PrimeOrderCalculatorAccelerator.Return(gpu);
@@ -95,7 +95,7 @@ public class PrimeOrderCalculatorTests
 			gpu,
 			prime,
 			previousOrder: null,
-			MontgomeryDivisorDataPool.Shared.FromModulus(prime),
+			MontgomeryDivisorData.FromModulus(prime),
 			PrimeOrderCalculator.PrimeOrderCalculatorConfig.HeuristicDefault);
 
 		PrimeOrderCalculatorAccelerator.Return(gpu);
@@ -117,7 +117,7 @@ public class PrimeOrderCalculatorTests
 			gpu,
 			prime: 13UL,
 			previousOrder: null,
-			MontgomeryDivisorDataPool.Shared.FromModulus(13UL),
+			MontgomeryDivisorData.FromModulus(13UL),
 			config);
 
 		PrimeOrderCalculatorAccelerator.Return(gpu);
@@ -137,7 +137,7 @@ public class PrimeOrderCalculatorTests
 		var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 		try
 		{
-			MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(239UL);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(239UL);
 			ulong heuristic = PrimeOrderCalculator.CalculateGpu(
 				gpu,
 				prime: 239UL,

PerfectNumbers.Core/Cpu/MersenneCpuDivisorScanSession.cs

@@ -5,20 +5,20 @@ namespace PerfectNumbers.Core.Cpu;
 
 internal sealed class MersenneCpuDivisorScanSession(PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice) : IMersenneNumberDivisorByDivisorTester.IDivisorScanSession
 {
-	private Func<ulong, ulong> _getCycleLength = orderDevice switch
+	private Func<ulong, MontgomeryDivisorData, ulong> _getCycleLength = orderDevice switch
 	{
-		ComputationDevice.Gpu => divisor => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor),
+		ComputationDevice.Gpu => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor, divisorData),
-		ComputationDevice.Hybrid => divisor => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor),
+		ComputationDevice.Hybrid => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor, divisorData),
-		_ => static (divisor) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor),
+		_ => static (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor, divisorData),
 	};
 
 	public void Configure(PrimeOrderCalculatorAccelerator gpu, ComputationDevice orderDevice)
 	{
 		_getCycleLength = orderDevice switch
 		{
-			ComputationDevice.Gpu => divisor => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor),
+			ComputationDevice.Gpu => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthGpu(gpu, divisor, divisorData),
-			ComputationDevice.Hybrid => divisor => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor),
+			ComputationDevice.Hybrid => (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthHybrid(gpu, divisor, divisorData),
-			_ => static (divisor) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor),
+			_ => static (divisor, divisorData) => DivisorCycleCache.Shared.GetCycleLengthCpu(divisor, divisorData),
 		};
 	}
 
@@ -45,7 +45,7 @@ internal sealed class MersenneCpuDivisorScanSession(PrimeOrderCalculatorAccelera
 
 		if (divisorCycle == 0UL)
 		{
-			divisorCycle = _getCycleLength(divisor);
+			divisorCycle = _getCycleLength(divisor, divisorData);
 			// This never kicks off in production code
 			// if (divisorCycle == 0UL)
 			// {

PerfectNumbers.Core/Cpu/MersenneNumberDivisorByDivisorCpuTester.cs

@@ -6,18 +6,29 @@ using PerfectNumbers.Core.Gpu.Accelerators;
 
 namespace PerfectNumbers.Core.Cpu;
 
-public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDivisorByDivisorTester
+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;
+    private readonly ComputationDevice OrderDevice = orderDevice;
-    private readonly TryCycleLengthDelegate _tryCalculateCycleLengthForExponent;
+    private readonly TryCycleLengthDelegate _tryCalculateCycleLengthForExponent = orderDevice switch
-    private readonly CalculateCycleLengthDelegate _calculateCycleLength;
+	{
+		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;
-	public ComputationDevice OrderDevice => _orderDevice;
 
 	private delegate bool TryCycleLengthDelegate(
 		ulong divisor,
@@ -43,24 +54,6 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
 		public GpuUInt128 Limit;
 	}
 
-	public MersenneNumberDivisorByDivisorCpuTester(ComputationDevice orderDevice = ComputationDevice.Hybrid)
-	{
-		_orderDevice = orderDevice;
-		_tryCalculateCycleLengthForExponent = orderDevice switch
-		{
-			ComputationDevice.Gpu => TryCalculateCycleLengthForExponentGpu,
-			ComputationDevice.Hybrid => TryCalculateCycleLengthForExponentHybrid,
-			_ => TryCalculateCycleLengthForExponentCpu,
-		};
-
-		_calculateCycleLength = orderDevice switch
-		{
-			ComputationDevice.Gpu => CalculateCycleLengthGpu,
-			ComputationDevice.Hybrid => CalculateCycleLengthHybrid,
-			_ => CalculateCycleLengthCpu,
-		};
-	}
-
 	public int BatchSize
 	{
 		get => _batchSize;
@@ -157,7 +150,7 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
     }
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu) => ThreadStaticPools.RentMersenneCpuDivisorSession(gpu, _orderDevice);
+	public IMersenneNumberDivisorByDivisorTester.IDivisorScanSession CreateDivisorSession(PrimeOrderCalculatorAccelerator gpu) => ThreadStaticPools.RentMersenneCpuDivisorSession(gpu, OrderDevice);
 
 	private bool CheckDivisors(
         PrimeOrderCalculatorAccelerator gpu,
@@ -340,13 +333,12 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
 		ulong divisorHigh = divisor.High;
 		var residueStepper = new MersenneDivisorResidueStepper(prime, step, divisor);
 
-		var divisorPool = MontgomeryDivisorDataPool.Shared;
 		while (divisor.CompareTo(limit) <= 0)
 		{
 			if (residueStepper.IsAdmissible())
 			{
 				ulong candidate = divisor.Low;
-				MontgomeryDivisorData divisorData = divisorPool.FromModulus(candidate);
+				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(
@@ -370,7 +362,6 @@ public sealed class MersenneNumberDivisorByDivisorCpuTester : IMersenneNumberDiv
 						divisorCycle = computedCycle;
 				}
 
-				divisorPool.Return(divisorData);
 				RecordState(currentK);
 				if (divisorCycle == prime)
 				{
@@ -553,12 +544,11 @@ private bool CheckDivisors64(
 		out ulong foundDivisor)
 	{
 		bool canAdvance = step <= limit;
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
 		if (!canAdvance)
 		{
 			if (divisor <= limit && residueStepper.IsAdmissible())
 			{
-				MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
+				MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 				ulong divisorCycle;
 				if (!_tryCalculateCycleLengthForExponent(
 						divisor,
@@ -579,8 +569,6 @@ private bool CheckDivisors64(
 					divisorCycle = computedCycle;
 				}
 
-				divisorPool.Return(divisorData);
-
 				if (divisorCycle == prime)
 				{
 					foundDivisor = divisor;
@@ -611,7 +599,7 @@ private bool CheckDivisors64(
 		{
 			if (residueStepper.IsAdmissible())
 			{
-				MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
+				MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 				ulong divisorCycle;
 				if (!_tryCalculateCycleLengthForExponent(
 						divisor,
@@ -632,7 +620,6 @@ private bool CheckDivisors64(
 					divisorCycle = computedCycle;
 				}
 
-				divisorPool.Return(divisorData);
 				RecordState(currentK);
 				if (divisorCycle == prime)
 				{

PerfectNumbers.Core/DivisorCycleCache.cs

@@ -19,22 +19,18 @@ public sealed class DivisorCycleCache
 	private static int _sharedDivisorCyclesBatchSize = GpuConstants.GpuCycleStepsPerInvocation;
 
 	private const int CycleCacheTrackingLimit = 500_000;
-	private static readonly HashSet<ulong> CycleCacheTrackedDivisors = new();
+	private static readonly HashSet<ulong> CycleCacheTrackedDivisors = [];
 	private static readonly object CycleCacheTrackingLock = new();
-	private static ulong CycleCacheHitCount;
-	private static bool CycleCacheTrackingDisabled;
 
 	public static void SetDivisorCyclesBatchSize(int divisorCyclesBatchSize)
 	{
 		_sharedDivisorCyclesBatchSize = Math.Max(1, divisorCyclesBatchSize);
 	}
 
-	public static DivisorCycleCache Shared { get; } = new DivisorCycleCache(_sharedDivisorCyclesBatchSize);
+	public static readonly DivisorCycleCache Shared = new(_sharedDivisorCyclesBatchSize);
 
 	public int PreferredBatchSize => _divisorCyclesBatchSize;
 
-	// private static readonly Accelerator[] _accelerators;
-
 	private DivisorCycleCache(int divisorCyclesBatchSize)
 	{
 		_divisorCyclesBatchSize = Math.Max(1, divisorCyclesBatchSize);
@@ -51,15 +47,28 @@ public sealed class DivisorCycleCache
 		_snapshot = MersenneDivisorCycles.Shared.ExportSmallCyclesSnapshot();
 	}
 
-	public ulong GetCycleLengthCpu(ulong divisor, bool skipPrimeOrderHeuristic = false)
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public ulong GetCycleLengthCpu(ulong divisor, in MontgomeryDivisorData divisorData)
+	{
+		ulong[] snapshot = _snapshot;
+
+		if (divisor < (ulong)snapshot.Length)
+		{
+			ulong cached = snapshot[divisor];
+			ArgumentOutOfRangeException.ThrowIfZero(cached);
+
+			return cached;
+		}
+
+		return MersenneDivisorCycles.CalculateCycleLengthCpu(divisor, divisorData);
+	}
+
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public ulong GetCycleLengthHybrid(PrimeOrderCalculatorAccelerator gpu, ulong divisor, in MontgomeryDivisorData divisorData, bool skipPrimeOrderHeuristic = false)
 	{
 		if (!skipPrimeOrderHeuristic)
 		{
-			// TODO: Implement array-free version of GetCycleLengthsCpu so that we don't pay the array costs for single checks.
+			return GetCycleLengthHybrid(gpu, divisor, divisorData);
-			Span<ulong> result = stackalloc ulong[1];
-			ReadOnlySpan<ulong> singleDivisor = stackalloc ulong[1] { divisor };
-			GetCycleLengthsCpu(singleDivisor, result);
-			return result[0];
 		}
 
 		// The skipPrimeOrderHeuristic path is only used for divisors produced by the CPU by-divisor scanner,
@@ -75,61 +84,17 @@ public sealed class DivisorCycleCache
 		if (divisor < (ulong)snapshot.Length)
 		{
 			cycleLength = snapshot[divisor];
-			if (cycleLength == 0UL)
+			ArgumentOutOfRangeException.ThrowIfZero(cycleLength);
-			{
-				throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-			}
 
 			return cycleLength;
 		}
 
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
-		MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
-		cycleLength = MersenneDivisorCycles.CalculateCycleLengthCpu(divisor, divisorData, skipPrimeOrderHeuristic: true);
-		divisorPool.Return(divisorData);
-		return cycleLength;
-	}
-
-	public ulong GetCycleLengthHybrid(PrimeOrderCalculatorAccelerator gpu, ulong divisor, bool skipPrimeOrderHeuristic = false)
-	{
-		if (!skipPrimeOrderHeuristic)
-		{
-			// TODO: Implement array-free version of GetCycleLengthsHybrid so that we don't pay the array costs for single checks.
-			Span<ulong> result = stackalloc ulong[1];
-			ReadOnlySpan<ulong> singleDivisor = stackalloc ulong[1] { divisor };
-			GetCycleLengthsHybrid(gpu, singleDivisor, result);
-			return result[0];
-		}
-
-		// The skipPrimeOrderHeuristic path is only used for divisors produced by the CPU by-divisor scanner,
-		// which always generates values greater than one. Keep this guard disabled here to avoid repeating the
-		// validation already performed by the general GetCycleLengths path.
-		// if (divisor <= 1UL)
-		// {
-		//     throw new InvalidDataException("Divisor must be > 1");
-		// }
-
-		ulong[] snapshot = _snapshot;
-		ulong cycleLength;
-		if (divisor < (ulong)snapshot.Length)
-		{
-			cycleLength = snapshot[divisor];
-			if (cycleLength == 0UL)
-			{
-				throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-			}
-
-			return cycleLength;
-		}
-
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
-		MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
 		cycleLength = MersenneDivisorCycles.CalculateCycleLengthHybrid(gpu, divisor, divisorData, skipPrimeOrderHeuristic: true);
-		divisorPool.Return(divisorData);
 		return cycleLength;
 	}
 
-	public ulong GetCycleLengthGpu(PrimeOrderCalculatorAccelerator gpu, ulong divisor, bool skipPrimeOrderHeuristic = false)
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public ulong GetCycleLengthGpu(PrimeOrderCalculatorAccelerator gpu, ulong divisor, in MontgomeryDivisorData	divisorData, bool skipPrimeOrderHeuristic = false)
 	{
 		if (!skipPrimeOrderHeuristic)
 		{
@@ -152,18 +117,12 @@ public sealed class DivisorCycleCache
 		if (divisor < (ulong)snapshot.Length)
 		{
 			cycleLength = snapshot[divisor];
-			if (cycleLength == 0UL)
+			ArgumentOutOfRangeException.ThrowIfZero(cycleLength);
-			{
-				throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-			}
 
 			return cycleLength;
 		}
 
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
-		MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
 		cycleLength = MersenneDivisorCycles.CalculateCycleLengthGpu(gpu, divisor, divisorData, skipPrimeOrderHeuristic: true);
-		divisorPool.Return(divisorData);
 		return cycleLength;
 	}
 
@@ -181,18 +140,11 @@ public sealed class DivisorCycleCache
 		for (int i = 0; i < length; i++)
 		{
 			ulong divisor = divisors[i];
-			if (divisor <= 1UL)
-			{
-				throw new InvalidDataException("Divisor must be > 1");
-			}
 
 			if (divisor < (ulong)snapshot.Length)
 			{
 				ulong cached = snapshot[divisor];
-				if (cached == 0UL)
+				ArgumentOutOfRangeException.ThrowIfZero(cached);
-				{
-					throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-				}
 
 				cycles[i] = cached;
 			}
@@ -214,6 +166,22 @@ public sealed class DivisorCycleCache
 		}
 	}
 
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public ulong GetCycleLengthHybrid(PrimeOrderCalculatorAccelerator gpu, ulong divisor, in MontgomeryDivisorData divisorData)
+	{
+		ulong[] snapshot = _snapshot;
+
+		if (divisor < (ulong)snapshot.Length)
+		{
+			ulong cached = snapshot[divisor];
+			ArgumentOutOfRangeException.ThrowIfZero(cached);
+
+			return cached;
+		}
+
+		return MersenneDivisorCycles.CalculateCycleLengthHybrid(gpu, divisor, divisorData);
+	}
+
 	public void GetCycleLengthsHybrid(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> divisors, Span<ulong> cycles)
 	{
 		ulong[] snapshot = _snapshot;
@@ -228,18 +196,11 @@ public sealed class DivisorCycleCache
 		for (int i = 0; i < length; i++)
 		{
 			ulong divisor = divisors[i];
-			if (divisor <= 1UL)
-			{
-				throw new InvalidDataException("Divisor must be > 1");
-			}
 
 			if (divisor < (ulong)snapshot.Length)
 			{
 				ulong cached = snapshot[divisor];
-				if (cached == 0UL)
+				ArgumentOutOfRangeException.ThrowIfZero(cached);
-				{
-					throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-				}
 
 				cycles[i] = cached;
 			}
@@ -275,18 +236,11 @@ public sealed class DivisorCycleCache
 		for (int i = 0; i < length; i++)
 		{
 			ulong divisor = divisors[i];
-			if (divisor <= 1UL)
-			{
-				throw new InvalidDataException("Divisor must be > 1");
-			}
 
 			if (divisor < (ulong)snapshot.Length)
 			{
 				ulong cached = snapshot[divisor];
-				if (cached == 0UL)
+				ArgumentOutOfRangeException.ThrowIfZero(cached);
-				{
-					throw new InvalidDataException($"Divisor cycle is missing for {divisor}");
-				}
 
 				cycles[i] = cached;
 			}
@@ -308,68 +262,27 @@ public sealed class DivisorCycleCache
 		}
 	}
 
-	private static void ObserveCycleCacheDivisor(ulong divisor)
-	{
-		bool logHit = false;
-		ulong hitNumber = 0UL;
-		bool trackingDisabledNow = false;
-
-		lock (CycleCacheTrackingLock)
-		{
-			if (CycleCacheTrackingDisabled)
-			{
-				return;
-			}
-
-			if (!CycleCacheTrackedDivisors.Add(divisor))
-			{
-				CycleCacheHitCount++;
-				hitNumber = CycleCacheHitCount;
-				logHit = true;
-			}
-			else if (CycleCacheTrackedDivisors.Count >= CycleCacheTrackingLimit)
-			{
-				CycleCacheTrackingDisabled = true;
-				CycleCacheTrackedDivisors.Clear();
-				trackingDisabledNow = true;
-			}
-		}
-
-		if (logHit)
-		{
-			Console.WriteLine($"Cycle cache hit for divisor {divisor} ({hitNumber})");
-		}
-		else if (trackingDisabledNow)
-		{
-			Console.WriteLine("Cycle cache hit tracking disabled after exceeding the tracking limit.");
-		}
-	}
-
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
 	private static void ComputeCyclesCpu(ReadOnlySpan<ulong> divisors, Span<ulong> cycles, ReadOnlySpan<int> indices)
 	{
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
 		for (int i = 0; i < indices.Length; i++)
 		{
 			int targetIndex = indices[i];
 			ulong divisor = divisors[targetIndex];
-			MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 			cycles[targetIndex] = MersenneDivisorCycles.CalculateCycleLengthCpu(divisor, divisorData);
-			divisorPool.Return(divisorData);
 		}
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
 	private static void ComputeCyclesHybrid(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> divisors, Span<ulong> cycles, ReadOnlySpan<int> indices)
 	{
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
 		for (int i = 0; i < indices.Length; i++)
 		{
 			int targetIndex = indices[i];
 			ulong divisor = divisors[targetIndex];
-			MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 			cycles[targetIndex] = MersenneDivisorCycles.CalculateCycleLengthHybrid(gpu, divisor, divisorData);
-			divisorPool.Return(divisorData);
 		}
 	}
 
@@ -408,44 +321,44 @@ public sealed class DivisorCycleCache
 	private const int DefaultCapacity = 128;
 
 	[ThreadStatic]
-	private static MemoryBuffer1D<ulong, Stride1D.Dense>? divisorBuffer;
+	private static MemoryBuffer1D<ulong, Stride1D.Dense>? _divisorBuffer;
 
 	[ThreadStatic]
-	private static MemoryBuffer1D<ulong, Stride1D.Dense>? powBuffer;
+	private static MemoryBuffer1D<ulong, Stride1D.Dense>? _powBuffer;
 
 	[ThreadStatic]
-	private static MemoryBuffer1D<ulong, Stride1D.Dense>? orderBuffer;
+	private static MemoryBuffer1D<ulong, Stride1D.Dense>? _orderBuffer;
 
 	[ThreadStatic]
-	private static MemoryBuffer1D<ulong, Stride1D.Dense>? resultBuffer;
+	private static MemoryBuffer1D<ulong, Stride1D.Dense>? _resultBuffer;
 
 	[ThreadStatic]
-	private static MemoryBuffer1D<byte, Stride1D.Dense>? statusBuffer;
+	private static MemoryBuffer1D<byte, Stride1D.Dense>? _statusBuffer;
 
 	private void EnsureCapacity(int requiredCapacity)
 	{
-		if (requiredCapacity <= (divisorBuffer?.Length ?? 0))
+		if (_divisorBuffer is not null && requiredCapacity <= _divisorBuffer.Length)
 		{
 			return;
 		}
 
-		if (divisorBuffer != null)
+		if (_divisorBuffer != null)
 		{
-			divisorBuffer.Dispose();
+			_divisorBuffer.Dispose();
-			powBuffer!.Dispose();
+			_powBuffer!.Dispose();
-			orderBuffer!.Dispose();
+			_orderBuffer!.Dispose();
-			resultBuffer!.Dispose();
+			_resultBuffer!.Dispose();
-			statusBuffer!.Dispose();
+			_statusBuffer!.Dispose();
 		}
 
 		Accelerator accelerator = _accelerator;
 		// lock (accelerator)
 		{
-			divisorBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
+			_divisorBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
-			powBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
+			_powBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
-			orderBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
+			_orderBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
-			resultBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
+			_resultBuffer = accelerator.Allocate1D<ulong>(requiredCapacity);
-			statusBuffer = accelerator.Allocate1D<byte>(requiredCapacity);
+			_statusBuffer = accelerator.Allocate1D<byte>(requiredCapacity);
 		}
 	}
 
@@ -496,17 +409,17 @@ public sealed class DivisorCycleCache
 		var acceleratorIndex = _acceleratorIndex;
 		var stream = AcceleratorStreamPool.Rent(acceleratorIndex);
 
-		divisorBuffer!.View.CopyFromCPU(stream, divisors);
+		_divisorBuffer!.View.CopyFromCPU(stream, divisors);
-		powBuffer!.View.CopyFromCPU(stream, powSpan);
+		_powBuffer!.View.CopyFromCPU(stream, powSpan);
-		orderBuffer!.View.CopyFromCPU(stream, orderSpan);
+		_orderBuffer!.View.CopyFromCPU(stream, orderSpan);
-		resultBuffer!.View.CopyFromCPU(stream, resultSpan);
+		_resultBuffer!.View.CopyFromCPU(stream, resultSpan);
-		statusBuffer!.View.CopyFromCPU(stream, statusSpan);
+		_statusBuffer!.View.CopyFromCPU(stream, statusSpan);
 
 		do
 		{
-			kernel(stream, length, _divisorCyclesBatchSize, divisorBuffer.View, powBuffer.View, orderBuffer.View, resultBuffer.View, statusBuffer.View);
+			kernel(stream, length, _divisorCyclesBatchSize, _divisorBuffer.View, _powBuffer.View, _orderBuffer.View, _resultBuffer.View, _statusBuffer.View);
 
-			statusBuffer.View.CopyToCPU(stream, statusSpan);
+			_statusBuffer.View.CopyToCPU(stream, statusSpan);
 			stream.Synchronize();
 
 			pending = 0;
@@ -520,7 +433,7 @@ public sealed class DivisorCycleCache
 		}
 		while (pending > 0);
 
-		resultBuffer.View.CopyToCPU(stream, resultSpan);
+		_resultBuffer.View.CopyToCPU(stream, resultSpan);
 		stream.Synchronize();
 		AcceleratorStreamPool.Return(acceleratorIndex, stream);
 

PerfectNumbers.Core/ExponentRemainderStepperCpu.cs

@@ -7,7 +7,7 @@ namespace PerfectNumbers.Core;
 /// Tracks successive Montgomery residues for a single divisor while scanning exponent candidates on the CPU path.
 /// Callers are responsible for seeding the stepper once per divisor and then advancing exponents in ascending order.
 /// </summary>
-internal struct ExponentRemainderStepperCpu(in MontgomeryDivisorData divisor, ulong cycleLength = 0UL)
+public struct ExponentRemainderStepperCpu(in MontgomeryDivisorData divisor, ulong cycleLength = 0UL)
 {
     private readonly MontgomeryDivisorData _divisor = divisor;
     private readonly ulong _modulus = divisor.Modulus;

PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs

@@ -17,10 +17,8 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 	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 object _sync = new();
 	private ulong _divisorLimit;
 	private BigInteger _minK = BigInteger.One;
-	// private bool _isConfigured;
 
 	private readonly ConcurrentFixedCapacityStack<MersenneNumberDivisorByDivisorAccelerator>[] _resourcePool = [.. AcceleratorPool.Shared.Accelerators.Select(x => new ConcurrentFixedCapacityStack<MersenneNumberDivisorByDivisorAccelerator>(PerfectNumberConstants.DefaultPoolCapacity))];
 
@@ -64,14 +62,8 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 	{
 		// EvenPerfectBitScanner configures the GPU tester once before scanning and never mutates the configuration afterwards,
 		// so synchronization and runtime configuration guards are unnecessary here.
-		// lock (_sync)
-		// {
-		//     _divisorLimit = ComputeDivisorLimitFromMaxPrimeGpu(maxPrime);
-		//     _isConfigured = true;
-		// }
 
 		_divisorLimit = ComputeDivisorLimitFromMaxPrimeGpu(maxPrime);
-		// _isConfigured = true;
 	}
 
 	public bool IsPrime(PrimeOrderCalculatorAccelerator gpu, ulong prime, out bool divisorsExhausted, out BigInteger divisor)
@@ -80,16 +72,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 		int batchCapacity;
 
 		// EvenPerfectBitScanner only calls into this tester after configuring it once, so we can read the cached values without locking.
-		// lock (_sync)
-		// {
-		//     if (!_isConfigured)
-		//     {
-		//         throw new InvalidOperationException("ConfigureFromMaxPrime must be called before using the tester.");
-		//     }
-
-		//     allowedMax = ComputeAllowedMaxDivisorGpu(prime, _divisorLimit);
-		//     batchCapacity = _gpuBatchSize;
-		// }
 
 		allowedMax = ComputeAllowedMaxDivisorGpu(prime, _divisorLimit);
 		batchCapacity = _gpuBatchSize;
@@ -103,7 +85,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 
 		bool composite;
 		bool coveredRange;
-		ulong processedCount;
 		ulong lastProcessed;
 
 		// GpuPrimeWorkLimiter();
@@ -135,8 +116,7 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 			resources.Counts,
 			resources.Cycles,
 			out lastProcessed,
-			out coveredRange,
+			out coveredRange);
-			out processedCount);
 
 		ReturnBatchResources(acceleratorIndex, resources);
 		// Monitor.Exit(gpuLease.ExecutionLock);
@@ -213,8 +193,7 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 		int[] counts,
 		ulong[] cycles,
 		out ulong lastProcessed,
-		out bool coveredRange,
+		out bool coveredRange)
-		out ulong processedCount)
 	{
 		int batchCapacity = (int)divisorDataBuffer.Length;
 		bool composite = false;
@@ -244,7 +223,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 		if (!hasCandidates)
 		{
 			coveredRange = true;
-			processedCount = processedCountLocal;
 			lastProcessed = lastProcessedLocal;
 			return false;
 		}
@@ -272,7 +250,7 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 		ArrayView1D<ulong, Stride1D.Dense> exponentViewDevice = exponentBuffer.View;
 		ArrayView1D<byte, Stride1D.Dense> hitsView = hitsBuffer.View;
 		ArrayView1D<int, Stride1D.Dense> hitIndexView = hitIndexBuffer.View;
-		FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+
 		static bool ProcessRange(
 			PrimeOrderCalculatorAccelerator gpu,
 			ulong prime,
@@ -291,7 +269,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 			Span<int> offsetSpan,
 			Span<int> countSpan,
 			Span<ulong> cycleSpan,
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool,
 			int chunkCountBaseline,
 			int acceleratorIndex,
 			ref bool composite,
@@ -341,8 +318,8 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 					if (localStepper.IsAdmissible())
 					{
 						ulong divisorValue = (ulong)nextDivisor128;
-						MontgomeryDivisorData montgomeryData = divisorPool.FromModulus(divisorValue);
+						MontgomeryDivisorData montgomeryData = MontgomeryDivisorData.FromModulus(divisorValue);
-						ulong divisorCycle = ResolveDivisorCycle(gpu, divisorValue, prime, in montgomeryData);
+						ulong divisorCycle = ResolveDivisorCycle(gpu, divisorValue, prime, montgomeryData);
 						if (divisorCycle == prime)
 						{
 							processedCountLocal += (ulong)(i + 1);
@@ -351,7 +328,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 							return false;
 						}
 
-						divisorPool.Return(montgomeryData);
 						divisorSpan[admissibleCount] = divisorValue;
 						divisorDataSpan[admissibleCount] = new GpuDivisorPartialData(divisorValue);
 						offsetSpan[admissibleCount] = admissibleCount;
@@ -434,7 +410,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 				offsetSpan,
 				countSpan,
 				cycleSpan,
-				divisorPool,
 				chunkCountBaseline,
 				acceleratorIndex,
 				ref composite,
@@ -446,7 +421,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 			if (composite)
 			{
 				coveredRange = true;
-				processedCount = processedCountLocal;
 				lastProcessed = lastProcessedLocal;
 				return true;
 			}
@@ -474,7 +448,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 				offsetSpan,
 				countSpan,
 				cycleSpan,
-				divisorPool,
 				chunkCountBaseline,
 				acceleratorIndex,
 				ref composite,
@@ -487,7 +460,6 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 
 		processedAll = processedTop && processedBottom;
 		coveredRange = composite || processedAll;
-		processedCount = processedCountLocal;
 		lastProcessed = lastProcessedLocal;
 		return composite;
 	}

PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs

@@ -163,7 +163,7 @@ internal static partial class PrimeOrderGpuHeuristics
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-	public static GpuPow2ModStatus TryPow2Mod(PrimeOrderCalculatorAccelerator gpu, ulong exponent, ulong prime, out ulong remainder, in MontgomeryDivisorData? divisorData)
+	public static GpuPow2ModStatus TryPow2Mod(PrimeOrderCalculatorAccelerator gpu, ulong exponent, ulong prime, out ulong remainder, in MontgomeryDivisorData divisorData)
 	{
 		Span<ulong> exponents = stackalloc ulong[1];
 		Span<ulong> remainders = stackalloc ulong[1];
@@ -175,7 +175,7 @@ internal static partial class PrimeOrderGpuHeuristics
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-	public static GpuPow2ModStatus TryPow2ModBatch(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> exponents, ulong prime, Span<ulong> remainders, in MontgomeryDivisorData? divisorData)
+	public static GpuPow2ModStatus TryPow2ModBatch(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> exponents, ulong prime, Span<ulong> remainders, in MontgomeryDivisorData divisorData)
 	{
 		// This will never occur in production code
 		// if (exponents.Length == 0)
@@ -364,7 +364,7 @@ internal static partial class PrimeOrderGpuHeuristics
 		return GpuPow2ModStatus.Success;
 	}
 
-	private static bool TryComputeOnGpu(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> exponents, ulong prime, MontgomeryDivisorData? divisorData, Span<ulong> results)
+	private static bool TryComputeOnGpu(PrimeOrderCalculatorAccelerator gpu, ReadOnlySpan<ulong> exponents, ulong prime, MontgomeryDivisorData divisorData, Span<ulong> results)
 	{
 		// GpuPrimeWorkLimiter.Acquire();
 		int acceleratorIndex = gpu.AcceleratorIndex;
@@ -379,10 +379,11 @@ internal static partial class PrimeOrderGpuHeuristics
 		var exponentBufferView = gpu.InputView;
 		var remainderBufferView = gpu.OutputUlongView;
 
-		if (divisorData is null)
+		// if (divisorData.Equals(MontgomeryDivisorData.Empty) is null)
-		{
+		// if (divisorData is null)
-			divisorData = MontgomeryDivisorData.Empty;
+		// {
-		}
+		// 	divisorData = MontgomeryDivisorData.Empty;
+		// }
 
 		AcceleratorStream? stream = AcceleratorStreamPool.Rent(acceleratorIndex);
 		exponentBufferView.CopyFromCPU(stream, exponents);

PerfectNumbers.Core/HeuristicCombinedPrimeTester.cs

@@ -483,7 +483,7 @@ public sealed class HeuristicCombinedPrimeTester
 	internal static HeuristicDivisorPreparation PrepareHeuristicDivisor(in HeuristicDivisorCandidate candidate)
 	{
 		ulong divisor = candidate.Value;
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(divisor);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 		bool hasCycleHint = TryGetCycleLengthHint(divisor, out ulong cycleLength);
 		return new(candidate, divisorData, cycleLength, hasCycleHint);
 	}

PerfectNumbers.Core/HeuristicPrimeTester.cs

@@ -413,7 +413,7 @@ public sealed class HeuristicPrimeTester
 	internal static HeuristicDivisorPreparation PrepareHeuristicDivisor(in HeuristicDivisorCandidate candidate)
 	{
 		ulong divisor = candidate.Value;
-		MontgomeryDivisorData divisorData = MontgomeryDivisorDataPool.Shared.FromModulus(divisor);
+		MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 		bool hasCycleHint = TryGetCycleLengthHint(divisor, out ulong cycleLength);
 		return new HeuristicDivisorPreparation(candidate, divisorData, cycleLength, hasCycleHint);
 	}

PerfectNumbers.Core/MersenneDivisorCycles.cs

@@ -394,10 +394,8 @@ public class MersenneDivisorCycles
 		if (divisor <= ulong.MaxValue)
 		{
 			ulong divisor64 = (ulong)divisor;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor64);
-			MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor64);
 			ulong cycle = CalculateCycleLengthCpu(divisor64, divisorData);
-			divisorPool.Return(divisorData);
 			return (UInt128)cycle;
 		}
 
@@ -441,10 +439,8 @@ public class MersenneDivisorCycles
 		if (divisor <= ulong.MaxValue)
 		{
 			ulong divisor64 = (ulong)divisor;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor64);
-			MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor64);
 			ulong cycle = CalculateCycleLengthHybrid(gpu, divisor64, divisorData);
-			divisorPool.Return(divisorData);
 			return (UInt128)cycle;
 		}
 
@@ -489,10 +485,8 @@ public class MersenneDivisorCycles
 		if (divisor <= ulong.MaxValue)
 		{
 			ulong divisor64 = (ulong)divisor;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor64);
-			MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor64);
 			ulong cycle = CalculateCycleLengthGpu(gpu, divisor64, divisorData);
-			divisorPool.Return(divisorData);
 			return (UInt128)cycle;
 		}
 
@@ -1168,7 +1162,6 @@ public class MersenneDivisorCycles
 				// (ulong divisor, ulong cycle)[] localCycles = ArrayPool<(ulong, ulong)>.Shared.Rent(checked((int)rangeLength));
 				int localCycleIndex = 0;
 
-				FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
 				var gpu = PrimeOrderCalculatorAccelerator.Rent(1);
 				for (ulong divisor = localStart; divisor <= localEnd; divisor++)
 				{
@@ -1188,9 +1181,8 @@ public class MersenneDivisorCycles
 					// TODO: Migrate this generation path to the shared
 					// unrolled-hex calculator so the CPU generator matches
 					// the GPU benchmark leader for large divisors.
-					MontgomeryDivisorData divisorData = divisorPool.FromModulus(divisor);
+					MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(divisor);
 					ulong cycle = CalculateCycleLengthGpu(gpu, divisor, divisorData);
-					divisorPool.Return(divisorData);
 					localCycles[localCycleIndex++] = (divisor, cycle);
 				}
 

PerfectNumbers.Core/MontgomeryDivisorData.cs

@@ -1,24 +1,46 @@
+using System.Runtime.CompilerServices;
+
 namespace PerfectNumbers.Core;
 
-public sealed class MontgomeryDivisorData
+public readonly struct MontgomeryDivisorData(ulong modulus, ulong nPrime, ulong montgomeryOne, ulong montgomeryTwo, ulong montgomeryTwoSquared)
 {
 	public static readonly MontgomeryDivisorData Empty = new();
-    public ulong Modulus;
-	public ulong NPrime;
-	public ulong MontgomeryOne;
-	public ulong MontgomeryTwo;
-	public ulong MontgomeryTwoSquared;
 
-	public MontgomeryDivisorData()
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	private static ulong ComputeMontgomeryResidue(UInt128 value, ulong modulus) => (ulong)(value % modulus);
+
+	private static ulong ComputeMontgomeryNPrime(ulong modulus)
 	{
+		ulong inv = modulus;
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		inv *= unchecked(2UL - modulus * inv);
+		return unchecked(0UL - inv);
 	}
 
-	public MontgomeryDivisorData(ulong modulus, ulong nPrime, ulong montgomeryOne, ulong montgomeryTwo, ulong montgomeryTwoSquared)
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+	public static MontgomeryDivisorData FromModulus(ulong modulus)
 	{
-		Modulus = modulus;
+		ulong nPrime = ComputeMontgomeryNPrime(modulus);
-		NPrime = nPrime;
+		ulong montgomeryOne = ComputeMontgomeryResidue(UInt128Numbers.OneShiftedLeft64, modulus);
-		MontgomeryOne = montgomeryOne;
+		ulong montgomeryTwo = ComputeMontgomeryResidue(UInt128Numbers.OneShiftedLeft64x2, modulus);
-		MontgomeryTwo = montgomeryTwo;
+		ulong montgomeryTwoSquared = ULongExtensions.MontgomeryMultiplyCpu(montgomeryTwo, montgomeryTwo, modulus, nPrime);
-		MontgomeryTwoSquared = montgomeryTwoSquared;
+
+		return new(
+			modulus,
+			nPrime,
+			montgomeryOne,
+			montgomeryTwo,
+			montgomeryTwoSquared);
 	}
+
+    public readonly ulong Modulus = modulus;
+	public readonly ulong NPrime = nPrime;
+	public readonly ulong MontgomeryOne = montgomeryOne;
+	public readonly ulong MontgomeryTwo = montgomeryTwo;
+	public readonly ulong MontgomeryTwoSquared = montgomeryTwoSquared;
 }

PerfectNumbers.Core/MontgomeryDivisorDataPool.cs

@@ -1,86 +0,0 @@
-using System.Runtime.CompilerServices;
-
-namespace PerfectNumbers.Core;
-
-public static class MontgomeryDivisorDataPool
-{
-	[ThreadStatic]
-	private static FixedCapacityStack<MontgomeryDivisorData>? _pool;
-	public static FixedCapacityStack<MontgomeryDivisorData> Shared
-	{
-		[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-		get => _pool ??= new(PerfectNumberConstants.DefaultPoolCapacity);
-	}
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	private static ulong ComputeMontgomeryResidue(UInt128 value, ulong modulus) => (ulong)(value % modulus);
-
-	private static ulong ComputeMontgomeryNPrime(ulong modulus)
-	{
-		ulong inv = modulus;
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		inv *= unchecked(2UL - modulus * inv);
-		return unchecked(0UL - inv);
-	}
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public static MontgomeryDivisorData Rent(ulong modulus, ulong nPrime, ulong montgomeryOne, ulong montgomeryTwo, ulong montgomeryTwoSquared)
-	{
-		var pool = _pool ??= new(PerfectNumberConstants.DefaultPoolCapacity);
-		if (pool.Pop() is { } pooled)
-		{
-			pooled.Modulus = modulus;
-			pooled.NPrime = nPrime;
-			pooled.MontgomeryOne = montgomeryOne;
-			pooled.MontgomeryTwo = montgomeryTwo;
-			pooled.MontgomeryTwoSquared = montgomeryTwoSquared;
-			return pooled;
-		}
-
-		return new(modulus, nPrime, montgomeryOne, montgomeryTwo, montgomeryTwoSquared);
-	}
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public static void Return(MontgomeryDivisorData divisorData) => _pool!.Push(divisorData);
-
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public static MontgomeryDivisorData FromModulus(this FixedCapacityStack<MontgomeryDivisorData> queue, ulong modulus)
-	{
-		ulong nPrime = ComputeMontgomeryNPrime(modulus);
-		ulong montgomeryOne = ComputeMontgomeryResidue(UInt128Numbers.OneShiftedLeft64, modulus);
-		ulong montgomeryTwo = ComputeMontgomeryResidue(UInt128Numbers.OneShiftedLeft64x2, modulus);
-		ulong montgomeryTwoSquared = ULongExtensions.MontgomeryMultiplyCpu(montgomeryTwo, montgomeryTwo, modulus, nPrime);
-
-		return queue.Rent(
-			modulus,
-			nPrime,
-			montgomeryOne,
-			montgomeryTwo,
-			montgomeryTwoSquared);
-	}
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public static MontgomeryDivisorData Rent(this FixedCapacityStack<MontgomeryDivisorData> queue, ulong modulus, ulong nPrime, ulong montgomeryOne, ulong montgomeryTwo, ulong montgomeryTwoSquared)
-	{
-		if (queue.Pop() is { } pooled)
-		{
-			pooled.Modulus = modulus;
-			pooled.NPrime = nPrime;
-			pooled.MontgomeryOne = montgomeryOne;
-			pooled.MontgomeryTwo = montgomeryTwo;
-			pooled.MontgomeryTwoSquared = montgomeryTwoSquared;
-			return pooled;
-		}
-
-		return new(modulus, nPrime, montgomeryOne, montgomeryTwo, montgomeryTwoSquared);
-	}
-
-	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-	public static void Return(this FixedCapacityStack<MontgomeryDivisorData> queue, MontgomeryDivisorData divisorData) => queue.Push(divisorData);
-}

PerfectNumbers.Core/PartialFactorResult.cs

@@ -2,7 +2,7 @@ using PerfectNumbers.Core.Gpu;
 
 namespace PerfectNumbers.Core
 {
-	public sealed class PartialFactorResult
+	public sealed class PartialFactorResult(in MontgomeryDivisorData divisorData)
 	{
 		[ThreadStatic]
 		private static PartialFactorResult? s_poolHead;
@@ -13,26 +13,27 @@ namespace PerfectNumbers.Core
 		public readonly List<PartialFactorPendingEntry> PendingFactors = new (PrimeOrderConstants.GpuSmallPrimeFactorSlots);
 		public readonly ulong[] StackCandidates = new ulong[PrimeOrderConstants.GpuSmallPrimeFactorSlots << 3];
 		public readonly bool[] StackEvaluations = new bool[PrimeOrderConstants.GpuSmallPrimeFactorSlots << 3];
+		public ExponentRemainderStepperCpu ExponentRemainderStepper = new(divisorData);
 		private PartialFactorResult? _next;
 		public ulong Cofactor;
 		public bool FullyFactored;
 		public int Count;
 		public bool CofactorIsPrime;
 
-		private PartialFactorResult()
+		public static PartialFactorResult Rent(in MontgomeryDivisorData divisorData)
-		{
-		}
-
-		public static PartialFactorResult Rent()
 		{
 			PartialFactorResult? instance = s_poolHead;
 			if (instance is null)
 			{
-				instance = new PartialFactorResult();
+				instance = new PartialFactorResult(divisorData);
 			}
 			else
 			{
 				s_poolHead = instance._next;
+				if (!instance.ExponentRemainderStepper.MatchesDivisor(divisorData, 0UL))
+				{
+					instance.ExponentRemainderStepper = new(divisorData, 0UL);
+				}
 			}
 
 			instance._next = null;
@@ -43,7 +44,7 @@ namespace PerfectNumbers.Core
 			return instance;
 		}
 
-		public static readonly PartialFactorResult Empty = new()
+		public static readonly PartialFactorResult Empty = new(MontgomeryDivisorData.Empty)
 		{
 			Cofactor = 1UL,
 			FullyFactored = true

PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs

@@ -25,7 +25,7 @@ internal static partial class PrimeOrderCalculator
 
 		ulong phi = prime - 1UL;
 
-		PartialFactorResult phiFactors = PartialFactorCpu(phi, config);
+		PartialFactorResult phiFactors = PartialFactorCpu(phi, divisorData, config);
 
 		ulong result;
 		if (phiFactors.Factors is null)
@@ -46,7 +46,6 @@ internal static partial class PrimeOrderCalculator
 			in UInt128? previousOrder,
 			in PrimeOrderCalculatorConfig config)
 	{		
-		MontgomeryDivisorData divisorData;
 		UInt128 result;
 		if (prime <= ulong.MaxValue)
 		{
@@ -65,16 +64,13 @@ internal static partial class PrimeOrderCalculator
 			}
 
 			ulong prime64 = (ulong)prime;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			MontgomeryDivisorData divisorData = MontgomeryDivisorData.FromModulus(prime64);
-			divisorData = divisorPool.FromModulus(prime64);
 			ulong order64 = CalculateCpu(prime64, previous, divisorData, config);
-			divisorPool.Return(divisorData);
 			result = order64 == 0UL ? UInt128.Zero : (UInt128)order64;
 		}
 		else
 		{
-			divisorData = MontgomeryDivisorData.Empty;
+			result = CalculateWideInternalCpu(prime, previousOrder, MontgomeryDivisorData.Empty, config);
-			result = CalculateWideInternalCpu(prime, previousOrder, divisorData, config);
 		}
 
 		return result;
@@ -561,7 +557,7 @@ internal static partial class PrimeOrderCalculator
 
 		SortFactorExponentSpans(factorsSpan, exponentsSpan, factorCount);
 
-		ExponentRemainderStepperCpu stepper = ThreadStaticPools.RentExponentStepperCpu(divisorData);
+		ExponentRemainderStepperCpu stepper = factors.ExponentRemainderStepper;
 
 		Span<ulong> stackCandidates = new(factors.StackCandidates);
 		Span<bool> stackEvaluations = new(factors.StackEvaluations);
@@ -579,7 +575,6 @@ internal static partial class PrimeOrderCalculator
 			ProcessExponentLoweringPrime(stackCandidates[..exponent], stackEvaluations[..exponent], ref order, primeFactor, exponent, ref stepper);
 		}
 
-		ThreadStaticPools.ReturnExponentStepperCpu(stepper);
 		return order;
 	}
 
@@ -673,7 +668,7 @@ internal static partial class PrimeOrderCalculator
 			return false;
 		}
 
-		PartialFactorResult factorization = PartialFactorCpu(order, config);
+		PartialFactorResult factorization = PartialFactorCpu(order, divisorData, config);
 		if (factorization.Factors is null)
 		{
 			factorization.Dispose();
@@ -810,7 +805,7 @@ internal static partial class PrimeOrderCalculator
 		}
 
 		// Reuse the partial factorization from TryConfirmOrderCpu when available.
-		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorCpu(order, config);
+		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorCpu(order, divisorData, config);
 		try
 		{
 			if (orderFactors.Factors is null)
@@ -1106,7 +1101,7 @@ internal static partial class PrimeOrderCalculator
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
 	private static bool TryConfirmCandidateCpu(ulong prime, ulong candidate, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config, ref int powUsed, int powBudget)
 	{
-		PartialFactorResult factorization = PartialFactorCpu(candidate, config);
+		PartialFactorResult factorization = PartialFactorCpu(candidate, divisorData, config);
 
 		if (factorization.Factors is null)
 		{
@@ -1270,7 +1265,7 @@ internal static partial class PrimeOrderCalculator
 		=> exponent.Pow2MontgomeryModWindowedConvertToStandardCpu(divisorData) == 1UL;
 
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-	private static PartialFactorResult PartialFactorCpu(ulong value, in PrimeOrderCalculatorConfig config)
+	private static PartialFactorResult PartialFactorCpu(ulong value, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config)
 	{
 		if (value <= 1UL)
 		{
@@ -1279,7 +1274,7 @@ internal static partial class PrimeOrderCalculator
 
 		// stackalloc is faster than pooling
 
-		var result = PartialFactorResult.Rent();
+		var result = PartialFactorResult.Rent(divisorData);
 		ulong[] factors = result.Factors;
 		Span<ulong> primeSlots = new(factors);
 		int[] exponents = result.Exponents;

PerfectNumbers.Core/PrimeOrderCalculator.Gpu.cs

@@ -76,7 +76,7 @@ internal static partial class PrimeOrderCalculator
 			return gpuOrder;
 		}
 
-		PartialFactorResult phiFactors = PartialFactorGpu(gpu, phi, config);
+		PartialFactorResult phiFactors = PartialFactorGpu(gpu, phi, divisorData, config);
 
 		ulong result;
 		if (phiFactors.Factors is null)
@@ -117,10 +117,8 @@ internal static partial class PrimeOrderCalculator
 			}
 
 			ulong prime64 = (ulong)prime;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			divisorData = MontgomeryDivisorData.FromModulus(prime64);
-			divisorData = divisorPool.FromModulus(prime64);
 			ulong order64 = CalculateGpu(gpu, prime64, previous, divisorData, config);
-			divisorPool.Return(divisorData);
 			result = order64 == 0UL ? UInt128.Zero : (UInt128)order64;
 		}
 		else
@@ -133,7 +131,7 @@ internal static partial class PrimeOrderCalculator
 	}
 	
     [MethodImpl(MethodImplOptions.AggressiveOptimization)]
-    private static UInt128 CalculateWideInternalGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128? previousOrder, in MontgomeryDivisorData? divisorData, in PrimeOrderCalculatorConfig config)
+    private static UInt128 CalculateWideInternalGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128? previousOrder, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config)
     {
         if (prime <= UInt128.One)
         {
@@ -233,7 +231,7 @@ internal static partial class PrimeOrderCalculator
 		return result != 0;
 	}
 
-    private static UInt128 ExponentLoweringWideGpu(PrimeOrderCalculatorAccelerator gpu, UInt128 order, in UInt128 prime, in MontgomeryDivisorData? divisorData, in PartialFactorResult128 factors)
+    private static UInt128 ExponentLoweringWideGpu(PrimeOrderCalculatorAccelerator gpu, UInt128 order, in UInt128 prime, in MontgomeryDivisorData divisorData, in PartialFactorResult128 factors)
     {
         ArrayPool<FactorEntry128> pool = ThreadStaticPools.FactorEntry128Pool;
         ReadOnlySpan<FactorEntry128> factorSpan = factors.Factors;
@@ -281,7 +279,7 @@ internal static partial class PrimeOrderCalculator
         return order;
     }
 
-    private static UInt128 FinishStrictlyWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in MontgomeryDivisorData? divisorData)
+    private static UInt128 FinishStrictlyWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in MontgomeryDivisorData divisorData)
     {
         UInt128 phi = prime - UInt128.One;
         Dictionary<UInt128, int> counts = new(capacity: 8);
@@ -320,7 +318,7 @@ internal static partial class PrimeOrderCalculator
         return order;
     }
 
-    private static UInt128 InitializeStartingOrderWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 phi, in MontgomeryDivisorData? divisorData)
+    private static UInt128 InitializeStartingOrderWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 phi, in MontgomeryDivisorData divisorData)
     {
         UInt128 order = phi;
         UInt128 mod8 = prime & (UInt128)7UL;
@@ -337,7 +335,7 @@ internal static partial class PrimeOrderCalculator
     }
 
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-	private static PartialFactorResult PartialFactorGpu(PrimeOrderCalculatorAccelerator gpu, ulong value, in PrimeOrderCalculatorConfig config)
+	private static PartialFactorResult PartialFactorGpu(PrimeOrderCalculatorAccelerator gpu, ulong value, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config)
 	{
 		if (value <= 1UL)
 		{
@@ -345,7 +343,7 @@ internal static partial class PrimeOrderCalculator
 		}
 
 		// stackalloc is faster than pooling
-		var result = PartialFactorResult.Rent();
+		var result = PartialFactorResult.Rent(divisorData);
 		ulong[] factors = result.Factors;
 		Span<ulong> primeSlots = new (factors);
 		int[] exponents = result.Exponents;
@@ -478,7 +476,7 @@ internal static partial class PrimeOrderCalculator
 	}
 
     [MethodImpl(MethodImplOptions.AggressiveOptimization)]
-    private static UInt128 Pow2ModWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 exponent, in UInt128 modulus, in MontgomeryDivisorData? divisorData)
+    private static UInt128 Pow2ModWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 exponent, in UInt128 modulus, in MontgomeryDivisorData divisorData)
     {
         if (modulus == UInt128.One)
         {
@@ -509,7 +507,7 @@ internal static partial class PrimeOrderCalculator
 		PrimeOrderCalculatorAccelerator gpu,
         in UInt128 prime,
         in UInt128? previousOrder,
-        in MontgomeryDivisorData? divisorData,
+        in MontgomeryDivisorData divisorData,
         in PrimeOrderCalculatorConfig config,
         in UInt128 phi,
         in PartialFactorResult128 phiFactors)
@@ -540,7 +538,7 @@ internal static partial class PrimeOrderCalculator
         return candidateOrder;
     }
 
-    private static bool TryConfirmCandidateWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 candidate, in PrimeOrderCalculatorConfig config, ref int powUsed, int powBudget, in MontgomeryDivisorData? divisorData)
+    private static bool TryConfirmCandidateWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 candidate, in PrimeOrderCalculatorConfig config, ref int powUsed, int powBudget, in MontgomeryDivisorData divisorData)
     {
         PartialFactorResult128 factorization = PartialFactorWide(candidate, config);
         if (factorization.Factors is null)
@@ -593,7 +591,7 @@ internal static partial class PrimeOrderCalculator
         return true;
     }
 
-    private static bool TryConfirmOrderWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 order, in MontgomeryDivisorData? divisorData, in PrimeOrderCalculatorConfig config)
+    private static bool TryConfirmOrderWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 prime, in UInt128 order, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config)
     {
         if (order == UInt128.Zero)
         {
@@ -670,7 +668,7 @@ internal static partial class PrimeOrderCalculator
 		}
 
 		// Reuse the partial factorization from TryConfirmOrderCpu when available.
-		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorGpu(gpu, order, config);
+		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorGpu(gpu, order, divisorData, config);
 		try
 		{
 			if (orderFactors.Factors is null)
@@ -854,7 +852,7 @@ internal static partial class PrimeOrderCalculator
         in UInt128 prime,
         in UInt128 order,
         in UInt128? previousOrder,
-        in MontgomeryDivisorData? divisorData,
+        in MontgomeryDivisorData divisorData,
         in PrimeOrderCalculatorConfig config,
         out UInt128 result)
     {
@@ -1023,7 +1021,7 @@ internal static partial class PrimeOrderCalculator
 		return true;
 	}
 
-    private static bool TrySpecialMaxWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 phi, in UInt128 prime, in MontgomeryDivisorData? divisorData, in PartialFactorResult128 factors)
+    private static bool TrySpecialMaxWideGpu(PrimeOrderCalculatorAccelerator gpu, in UInt128 phi, in UInt128 prime, in MontgomeryDivisorData divisorData, in PartialFactorResult128 factors)
     {
         ReadOnlySpan<FactorEntry128> factorSpan = factors.Factors;
         int length = factors.Count;

PerfectNumbers.Core/PrimeOrderCalculator.Hybrid.cs

@@ -25,7 +25,7 @@ internal static partial class PrimeOrderCalculator
 
 		ulong phi = prime - 1UL;
 
-		PartialFactorResult phiFactors = PartialFactorHybrid(gpu, phi, config);
+		PartialFactorResult phiFactors = PartialFactorHybrid(gpu, phi, divisorData, config);
 
 		ulong result;
 		if (phiFactors.Factors is null)
@@ -67,10 +67,8 @@ internal static partial class PrimeOrderCalculator
 			}
 
 			ulong prime64 = (ulong)prime;
-			FixedCapacityStack<MontgomeryDivisorData> divisorPool = MontgomeryDivisorDataPool.Shared;
+			divisorData = MontgomeryDivisorData.FromModulus(prime64);
-			divisorData = divisorPool.FromModulus(prime64);
 			ulong order64 = CalculateHybrid(gpu, prime64, previous, divisorData, config);
-			divisorPool.Return(divisorData);
 			result = order64 == 0UL ? UInt128.Zero : (UInt128)order64;
 		}
 		else
@@ -134,7 +132,7 @@ internal static partial class PrimeOrderCalculator
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-	private static PartialFactorResult PartialFactorHybrid(PrimeOrderCalculatorAccelerator gpu, ulong value, in PrimeOrderCalculatorConfig config)
+	private static PartialFactorResult PartialFactorHybrid(PrimeOrderCalculatorAccelerator gpu, ulong value, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config)
 	{
 		if (value <= 1UL)
 		{
@@ -143,7 +141,7 @@ internal static partial class PrimeOrderCalculator
 
 		// stackalloc is faster than pooling
 
-		var result = PartialFactorResult.Rent();
+		var result = PartialFactorResult.Rent(divisorData);
 		ulong[] factors = result.Factors;
 		Span<ulong> primeSlots = new(factors);
 		int[] exponents = result.Exponents;
@@ -369,7 +367,7 @@ internal static partial class PrimeOrderCalculator
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
 	private static bool TryConfirmCandidateHybrid(PrimeOrderCalculatorAccelerator gpu, ulong prime, ulong candidate, in MontgomeryDivisorData divisorData, in PrimeOrderCalculatorConfig config, ref int powUsed, int powBudget)
 	{
-		PartialFactorResult factorization = PartialFactorHybrid(gpu, candidate, config);
+		PartialFactorResult factorization = PartialFactorHybrid(gpu, candidate, divisorData, config);
 
 		if (factorization.Factors is null)
 		{
@@ -466,7 +464,7 @@ internal static partial class PrimeOrderCalculator
 			return false;
 		}
 
-		PartialFactorResult factorization = PartialFactorHybrid(gpu, order, config);
+		PartialFactorResult factorization = PartialFactorHybrid(gpu, order, divisorData, config);
 		if (factorization.Factors is null)
 		{
 			factorization.Dispose();
@@ -514,7 +512,7 @@ internal static partial class PrimeOrderCalculator
 		}
 
 		// Reuse the partial factorization from TryConfirmOrderCpu when available.
-		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorHybrid(gpu, order, config);
+		PartialFactorResult orderFactors = cachedOrderFactors ?? PartialFactorHybrid(gpu, order, divisorData, config);
 		try
 		{
 			if (orderFactors.Factors is null)

PerfectNumbers.Core/ThreadStaticPools.cs

@@ -182,15 +182,6 @@ namespace PerfectNumbers.Core
 			get => _bytePool ??= ArrayPool<byte>.Create();
 		}
 
-		[ThreadStatic]
-		private static ArrayPool<MontgomeryDivisorData>? _montgomeryDivisorDataPool;
-
-		public static ArrayPool<MontgomeryDivisorData> MontgomeryDivisorDataPool
-		{
-			[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-			get => _montgomeryDivisorDataPool ??= ArrayPool<MontgomeryDivisorData>.Create();
-		}
-
 		[ThreadStatic]
 		private static ArrayPool<GpuDivisorPartialData>? _gpuDivisorPartialDataPool;
 

PerfectNumbers.Core/UInt128Extensions.cs

@@ -510,38 +510,38 @@ public static class UInt128Extensions
 		ulong rightLow = (ulong)right;
 		ulong rightHigh = (ulong)(right >> 64);
 
-		var partial0 = Multiply64(leftLow, rightLow);
+		(ulong carry, p0) = Multiply64(leftLow, rightLow);
-		var partial1 = Multiply64(leftLow, rightHigh);
+		(ulong partial1High, ulong partial1Low) = Multiply64(leftLow, rightHigh);
-		var partial2 = Multiply64(leftHigh, rightLow);
-		var partial3 = Multiply64(leftHigh, rightHigh);
 
-		p0 = partial0.Low;
+		ulong sum = carry + partial1Low;
-		ulong carry = partial0.High;
+		carry = sum < partial1Low ? 1UL : 0UL;
-		ulong sum = carry + partial1.Low;
+
-		ulong carryMid = sum < partial1.Low ? 1UL : 0UL;
+		(ulong partial2High, ulong partial2Low) = Multiply64(leftHigh, rightLow);
-		sum += partial2.Low;
+		sum += partial2Low;
-		if (sum < partial2.Low)
+		if (sum < partial2Low)
 		{
-			carryMid++;
+			carry++;
 		}
 
 		p1 = sum;
-		sum = partial1.High + partial2.High;
+		sum = partial1High + partial2High;
-		ulong carryHigh = sum < partial2.High ? 1UL : 0UL;
+		partial2High = sum < partial2High ? 1UL : 0UL;
-		sum += partial3.Low;
+
-		if (sum < partial3.Low)
+		(partial1High, partial1Low) = Multiply64(leftHigh, rightHigh);
+		sum += partial1Low;
+		if (sum < partial1Low)
 		{
-			carryHigh++;
+			partial2High++;
 		}
 
-		sum += carryMid;
+		sum += carry;
-		if (sum < carryMid)
+		if (sum < carry)
 		{
-			carryHigh++;
+			partial2High++;
 		}
 
 		p2 = sum;
-		p3 = partial3.High + carryHigh;
+		p3 = partial1High + partial2High;
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]