Add optimized modulo helpers for unsigned integers

This commit is contained in:
Marek Lemańczyk committed 2025-09-21 10:14:26 +02:00
1 parent 2c2bc62cb2
commit 95a0b030f6
7 files changed
+425 -84

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@@ -209,6 +209,30 @@ public class UInt128ExtensionsTests
value.Mod5().Should().Be((ulong)(value % 5));
}
[Fact]
[Trait("Category", "Fast")]
public void Mod7_matches_operator()
{
UInt128 value = (UInt128.One << 100) + 9876543210987654321UL;
value.Mod7().Should().Be((ulong)(value % 7));
}
[Fact]
[Trait("Category", "Fast")]
public void Mod11_matches_operator()
{
UInt128 value = (UInt128.One << 120) + 9876543210987654321UL;
value.Mod11().Should().Be((ulong)(value % 11));
}
[Fact]
[Trait("Category", "Fast")]
public void Mod128_matches_operator()
{
UInt128 value = (UInt128.One << 120) + 9876543210987654321UL;
value.Mod128().Should().Be((ulong)(value % 128));
}
[Fact]
[Trait("Category", "Fast")]
public void Mul64_matches_expected_product()
@@ -0,0 +1,85 @@
using FluentAssertions;
using Xunit;
namespace PerfectNumbers.Core.Tests;
public class UIntExtensionsTests
{
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod3_matches_operator(uint value)
{
value.Mod3().Should().Be(value % 3U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod5_matches_operator(uint value)
{
value.Mod5().Should().Be(value % 5U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod7_matches_operator(uint value)
{
value.Mod7().Should().Be(value % 7U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod8_matches_operator(uint value)
{
value.Mod8().Should().Be(value % 8U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod10_matches_operator(uint value)
{
value.Mod10().Should().Be(value % 10U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod11_matches_operator(uint value)
{
value.Mod11().Should().Be(value % 11U);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0U)]
[InlineData(1U)]
[InlineData(1234567890U)]
[InlineData(uint.MaxValue)]
public void Mod128_matches_operator(uint value)
{
value.Mod128().Should().Be(value % 128U);
}
}
@@ -21,6 +21,86 @@ public class ULongExtensionsTests
ULongExtensions.Mod10(value).Should().Be(expected);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod3_matches_operator(ulong value)
{
value.Mod3().Should().Be(value % 3UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod5_matches_operator(ulong value)
{
value.Mod5().Should().Be(value % 5UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod7_matches_operator(ulong value)
{
value.Mod7().Should().Be(value % 7UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod8_matches_operator(ulong value)
{
value.Mod8().Should().Be(value % 8UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod11_matches_operator(ulong value)
{
value.Mod11().Should().Be(value % 11UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(0UL)]
[InlineData(ulong.MaxValue)]
[InlineData(1234567890123456789UL)]
public void Mod128_matches_operator(ulong value)
{
value.Mod128().Should().Be(value % 128UL);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(1UL)]
[InlineData(123456789UL)]
[InlineData(ulong.MaxValue)]
public void Mod10_8_5_3Steps_matches_manual_formula(ulong value)
{
value.Mod10_8_5_3Steps(out ulong step10, out ulong step8, out ulong step5, out ulong step3);
ulong expected10 = ((value % 10UL) << 1) % 10UL;
ulong expected8 = ((value & 7UL) << 1) & 7UL;
ulong expected5 = ((value % 5UL) << 1) % 5UL;
ulong expected3 = ((value % 3UL) << 1) % 3UL;
step10.Should().Be(expected10);
step8.Should().Be(expected8);
step5.Should().Be(expected5);
step3.Should().Be(expected3);
}
[Theory]
[Trait("Category", "Fast")]
[InlineData(2UL, true)]
@@ -24,10 +24,7 @@ public class MersenneNumberResidueGpuTester(bool useGpuOrder)
UInt128 kStart = 1UL;
byte last = lastIsSeven ? (byte)1 : (byte)0;
var kernel = gpuLease.Pow2ModKernel;
ulong step10 = (exponent.Mod10() << 1).Mod10();
ulong step8 = ((exponent & 7UL) << 1) & 7UL;
ulong step3 = ((exponent % 3UL) << 1) % 3UL;
ulong step5 = ((exponent % 5UL) << 1) % 5UL;
exponent.Mod10_8_5_3Steps(out ulong step10, out ulong step8, out ulong step5, out ulong step3);
GpuUInt128 twoPGpu = (GpuUInt128)twoP;
var orderBuffer = accelerator.Allocate1D<ulong>(batchSize);
+60 -35
View File
@@ -203,48 +203,73 @@ public static class UInt128Extensions
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod10(this UInt128 value)
{
UInt128 zero = UInt128.Zero;
if (value == zero)
return 0UL;
public static ulong Mod10(this UInt128 value)
{
UInt128 zero = UInt128.Zero;
if (value == zero)
return 0UL;
ulong result = (ulong)value;
UInt128 high = value >> 64;
ulong result = (ulong)value;
UInt128 high = value >> 64;
while (high != zero)
{
// 2^64 ≡ 6 (mod 10)
result = (result + (ulong)high * 6UL).Mod10();
high >>= 64;
}
while (high != zero)
{
// 2^64 ≡ 6 (mod 10)
result = (result + (ulong)high * 6UL).Mod10();
high >>= 64;
}
return result.Mod10();
}
return result.Mod10();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod8(this UInt128 value) => (ulong)value & 7UL;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod3(this UInt128 value)
{
// 2^64 ≡ 1 (mod 3)
ulong rem = ((ulong)value % 3UL) + ((ulong)(value >> 64) % 3UL);
return rem >= 3UL ? rem - 3UL : rem;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod8(this UInt128 value) => (ulong)value & 7UL;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod5(this UInt128 value)
{
// 2^64 ≡ 1 (mod 5)
ulong rem = ((ulong)value % 5UL) + ((ulong)(value >> 64) % 5UL);
return rem >= 5UL ? rem - 5UL : rem;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod3(this UInt128 value)
{
ulong remainder = ((ulong)value).Mod3() + ((ulong)(value >> 64)).Mod3();
return remainder >= 3UL ? remainder - 3UL : remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod5(this UInt128 value)
{
ulong remainder = ((ulong)value).Mod5() + ((ulong)(value >> 64)).Mod5();
return remainder >= 5UL ? remainder - 5UL : remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod7(this UInt128 value)
{
ulong remainder = ((ulong)value).Mod7() + ((ulong)(value >> 64)).Mod7() * 2UL;
while (remainder >= 7UL)
{
remainder -= 7UL;
}
return remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod11(this UInt128 value)
{
ulong remainder = ((ulong)value).Mod11() + ((ulong)(value >> 64)).Mod11() * 5UL;
while (remainder >= 11UL)
{
remainder -= 11UL;
}
return remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod128(this UInt128 value) => (ulong)value & 127UL;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static UInt128 Mul64(this UInt128 a, UInt128 b)
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static UInt128 Mul64(this UInt128 a, UInt128 b)
{
ulong aLow = (ulong)a;
ulong bLow = (ulong)b;
return ((UInt128)(aLow * (ulong)(b >> 64) + aLow.MulHigh(bLow)) << 64) | (aLow * bLow);
+61
View File
@@ -0,0 +1,61 @@
using System.Runtime.CompilerServices;
namespace PerfectNumbers.Core;
public static class UIntExtensions
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod3(this uint value) => PerfectNumbersMath.FastRemainder3(value);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod5(this uint value) => PerfectNumbersMath.FastRemainder5(value);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod7(this uint value)
{
uint remainder = 0U;
uint temp = value;
while (temp != 0U)
{
remainder += temp & 7U;
temp >>= 3;
if (remainder >= 7U)
{
remainder -= 7U;
}
}
return remainder >= 7U ? remainder - 7U : remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod8(this uint value) => value & 7U;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod10(this uint value)
{
uint quotient = (uint)(((ulong)value * 0xCCCCCCCDUL) >> 35);
return value - quotient * 10U;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod11(this uint value)
{
uint remainder = 0U;
uint temp = value;
while (temp != 0U)
{
remainder += temp & 1023U;
temp >>= 10;
remainder -= 11U * (remainder / 11U);
}
return remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static uint Mod128(this uint value) => value & 127U;
}
+114 -45
View File
@@ -58,51 +58,62 @@ public static class ULongExtensions
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void Mod10_8_5_3(this ulong value, out ulong mod10, out ulong mod8, out ulong mod5, out ulong mod3)
{
ulong temp = value;
uint byteSum = 0U;
public static void Mod10_8_5_3(this ulong value, out ulong mod10, out ulong mod8, out ulong mod5, out ulong mod3)
{
ulong temp = value;
uint byteSum = 0U;
do
{
byteSum += (byte)temp;
temp >>= 8;
}
while (temp != 0UL);
do
{
byteSum += (byte)temp;
temp >>= 8;
}
while (temp != 0UL);
mod8 = value & 7UL;
mod8 = value & 7UL;
uint mod5Value = PerfectNumbersMath.FastRemainder5(byteSum);
uint mod3Value = PerfectNumbersMath.FastRemainder3(byteSum);
uint mod5Value = PerfectNumbersMath.FastRemainder5(byteSum);
uint mod3Value = PerfectNumbersMath.FastRemainder3(byteSum);
ulong parity = mod8 & 1UL;
mod10 = parity == 0UL
? mod5Value switch
{
0U => 0UL,
1U => 6UL,
2U => 2UL,
3U => 8UL,
_ => 4UL,
}
: mod5Value switch
{
0U => 5UL,
1U => 1UL,
2U => 7UL,
3U => 3UL,
_ => 9UL,
};
ulong parity = mod8 & 1UL;
mod10 = parity == 0UL
? mod5Value switch
{
0U => 0UL,
1U => 6UL,
2U => 2UL,
3U => 8UL,
_ => 4UL,
}
: mod5Value switch
{
0U => 5UL,
1U => 1UL,
2U => 7UL,
3U => 3UL,
_ => 9UL,
};
mod5 = mod5Value;
mod3 = mod3Value;
}
mod5 = mod5Value;
mod3 = mod3Value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsPrimeCandidate(this ulong n)
{
int i = 0;
ulong p;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void Mod10_8_5_3Steps(this ulong value, out ulong step10, out ulong step8, out ulong step5, out ulong step3)
{
value.Mod10_8_5_3(out ulong mod10, out ulong mod8, out ulong mod5, out ulong mod3);
step10 = (mod10 << 1).Mod10();
step8 = ((mod8 << 1) & 7UL);
step5 = (mod5 << 1).Mod5();
step3 = (mod3 << 1).Mod3();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsPrimeCandidate(this ulong n)
{
int i = 0;
ulong p;
uint[] smallPrimes = PrimesGenerator.SmallPrimes;
ulong[] smallPrimesPow2 = PrimesGenerator.SmallPrimesPow2;
int len = smallPrimes.Length;
@@ -123,12 +134,70 @@ public static class ULongExtensions
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod10(this ulong value)
{
ulong quotient = (ulong)(((UInt128)value * 0xCCCCCCCCCCCCCCCDUL) >> 67);
return value - quotient * 10UL;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod10(this ulong value)
{
ulong quotient = (ulong)(((UInt128)value * 0xCCCCCCCCCCCCCCCDUL) >> 67);
return value - quotient * 10UL;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod8(this ulong value) => value & 7UL;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod3(this ulong value)
{
uint sum = (uint)(value & 0xFFFFUL);
sum += (uint)((value >> 16) & 0xFFFFUL);
sum += (uint)((value >> 32) & 0xFFFFUL);
sum += (uint)((value >> 48) & 0xFFFFUL);
return PerfectNumbersMath.FastRemainder3(sum);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod5(this ulong value)
{
uint sum = (uint)(value & 0xFFFFUL);
sum += (uint)((value >> 16) & 0xFFFFUL);
sum += (uint)((value >> 32) & 0xFFFFUL);
sum += (uint)((value >> 48) & 0xFFFFUL);
return PerfectNumbersMath.FastRemainder5(sum);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod7(this ulong value)
{
uint low = (uint)value;
uint high = (uint)(value >> 32);
ulong remainder = low.Mod7() + (ulong)high.Mod7() * 4UL;
while (remainder >= 7UL)
{
remainder -= 7UL;
}
return remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod11(this ulong value)
{
uint low = (uint)value;
uint high = (uint)(value >> 32);
ulong remainder = low.Mod11() + (ulong)high.Mod11() * 4UL;
while (remainder >= 11UL)
{
remainder -= 11UL;
}
return remainder;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ulong Mod128(this ulong value) => value & 127UL;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static UInt128 Mul64(this ulong a, ulong b) => ((UInt128)a.MulHigh(b) << 64) | (UInt128)(a * b);