103 lines
2.8 KiB
C#
103 lines
2.8 KiB
C#
namespace PerfectNumbers.Core;
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internal static partial class PrimeOrderCalculator
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{
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internal enum PrimeOrderMode
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{
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Heuristic,
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Strict,
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}
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internal readonly struct PrimeOrderSearchConfig(uint smallFactorLimit, int pollardRhoMilliseconds, int maxPowChecks, PrimeOrderMode mode)
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{
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private static PrimeOrderSearchConfig _heuristicDefault = CreateHeuristicDefault(UnboundedTaskScheduler.ConfiguredThreadCount);
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public static PrimeOrderSearchConfig HeuristicDefault
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{
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get
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{
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return _heuristicDefault;
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}
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}
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public static readonly PrimeOrderSearchConfig StrictDefault = new(smallFactorLimit: 1_000_000, pollardRhoMilliseconds: 0, maxPowChecks: 0, PrimeOrderMode.Strict);
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public static void ConfigureHeuristicDefault(int threadCount)
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{
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_heuristicDefault = CreateHeuristicDefault(threadCount);
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}
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public static PrimeOrderSearchConfig CreateHeuristicDefault(int threadCount)
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{
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int normalizedThreadCount = threadCount < 1 ? 1 : threadCount;
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return new(smallFactorLimit: 100_000, pollardRhoMilliseconds: normalizedThreadCount * 24, maxPowChecks: 24, PrimeOrderMode.Heuristic);
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}
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public readonly uint SmallFactorLimit = smallFactorLimit;
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public readonly int PollardRhoMilliseconds = pollardRhoMilliseconds;
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public readonly int MaxPowChecks = maxPowChecks;
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public readonly PrimeOrderMode Mode = mode;
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}
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internal enum PrimeOrderHeuristicDevice
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{
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Cpu,
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Gpu,
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}
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// TODO: Remove branching on the CPU / GPU paths
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// TODO: Split big non-static functions into smaller / extract static code to limit JIT time
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public static ulong Calculate(
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ulong prime,
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ulong? previousOrder,
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in MontgomeryDivisorData divisorData,
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in PrimeOrderSearchConfig config,
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PrimeOrderHeuristicDevice device)
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{
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var scope = UsePow2Mode(device);
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ulong order = CalculateInternal(prime, previousOrder, divisorData, config);
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scope.Dispose();
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return order;
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}
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public static UInt128 Calculate(
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in UInt128 prime,
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in UInt128? previousOrder,
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in PrimeOrderSearchConfig config,
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in PrimeOrderHeuristicDevice device)
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{
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var scope = UsePow2Mode(device);
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MontgomeryDivisorData divisorData;
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UInt128 result;
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if (prime <= ulong.MaxValue)
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{
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ulong? previous = null;
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if (previousOrder.HasValue)
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{
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UInt128 previousValue = previousOrder.Value;
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if (previousValue <= ulong.MaxValue)
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{
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previous = (ulong)previousValue;
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}
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else
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{
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previous = ulong.MaxValue;
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}
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}
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ulong prime64 = (ulong)prime;
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divisorData = MontgomeryDivisorData.FromModulus(prime64);
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ulong order64 = Calculate(prime64, previous, divisorData, config, device);
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result = order64 == 0UL ? UInt128.Zero : (UInt128)order64;
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}
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else
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{
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divisorData = default;
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result = CalculateWideInternal(prime, previousOrder, divisorData, config);
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}
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scope.Dispose();
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return result;
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}
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}
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