81 lines
2.5 KiB
C#
81 lines
2.5 KiB
C#
using System;
|
|
using System.Numerics;
|
|
using FluentAssertions;
|
|
using PerfectNumbers.Core.Gpu.Kernels;
|
|
using Xunit;
|
|
|
|
namespace PerfectNumbers.Core.Tests;
|
|
|
|
public class BitContradictionKernelsTests
|
|
{
|
|
[Theory]
|
|
[Trait("Category", "Fast")]
|
|
[InlineData(31UL, 0UL, 0)]
|
|
[InlineData(31UL, 0UL, 5)]
|
|
[InlineData(61UL, 7UL, 3)]
|
|
[InlineData(36721UL, 1UL, 0)]
|
|
public void TryBuildQWordsFromBatchIndex_matches_BigInteger(ulong exponent, ulong batchIndex, int batchOffset)
|
|
{
|
|
int wordCount = BitContradictionKernels.MaxQWordCount;
|
|
ulong[] batchIndexWords = new ulong[wordCount];
|
|
batchIndexWords[0] = batchIndex;
|
|
|
|
ulong[] qWords = new ulong[wordCount];
|
|
bool ok = BitContradictionKernels.TryBuildQWordsFromBatchIndex(
|
|
exponent,
|
|
batchIndexWords,
|
|
wordCount,
|
|
batchOffset,
|
|
qWords,
|
|
out int qBitLen);
|
|
|
|
ok.Should().BeTrue();
|
|
|
|
BigInteger expectedK = ((BigInteger)batchIndex * BitContradictionKernels.BatchCount) + BigInteger.One + batchOffset;
|
|
BigInteger expectedQ = (expectedK * (exponent << 1)) + BigInteger.One;
|
|
BigInteger actualQ = ReadBigIntegerFromWords(qWords);
|
|
|
|
actualQ.Should().Be(expectedQ);
|
|
qBitLen.Should().Be(GetBitLength(expectedQ));
|
|
}
|
|
|
|
private static BigInteger ReadBigIntegerFromWords(ReadOnlySpan<ulong> words)
|
|
{
|
|
byte[] bytes = new byte[words.Length * sizeof(ulong)];
|
|
for (int w = 0; w < words.Length; w++)
|
|
{
|
|
ulong word = words[w];
|
|
int byteIndex = w << 3;
|
|
bytes[byteIndex] = (byte)word;
|
|
bytes[byteIndex + 1] = (byte)(word >> 8);
|
|
bytes[byteIndex + 2] = (byte)(word >> 16);
|
|
bytes[byteIndex + 3] = (byte)(word >> 24);
|
|
bytes[byteIndex + 4] = (byte)(word >> 32);
|
|
bytes[byteIndex + 5] = (byte)(word >> 40);
|
|
bytes[byteIndex + 6] = (byte)(word >> 48);
|
|
bytes[byteIndex + 7] = (byte)(word >> 56);
|
|
}
|
|
|
|
return new BigInteger(bytes, isUnsigned: true, isBigEndian: false);
|
|
}
|
|
|
|
private static int GetBitLength(BigInteger value)
|
|
{
|
|
if (value.IsZero)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
byte[] bytes = value.ToByteArray(isUnsigned: true, isBigEndian: false);
|
|
int last = bytes[^1];
|
|
int bits = (bytes.Length - 1) * 8;
|
|
while (last != 0)
|
|
{
|
|
bits++;
|
|
last >>= 1;
|
|
}
|
|
|
|
return bits;
|
|
}
|
|
}
|