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Use divisor squares to bound heuristic combined trial division

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Marek Lemańczyk committed 2025-10-29 15:13:54 +01:00
1 parent 4ab77ba170
commit b0158a844a
4 files changed
+351 -235
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PerfectNumbers.Core/HeuristicPrimeTester.cs
+91 -119
View File
@@ -263,167 +263,139 @@ public sealed class HeuristicPrimeTester
int batchCapacity = HeuristicGpuDivisorBatchSize;
int interleaveBatchSize = HeuristicDivisorInterleaveBatchSize;
var divisorPool = ThreadStaticPools.UlongPool;
var hitPool = ThreadStaticPools.BytePool;
ulong[] divisorArray = divisorPool.Rent(batchCapacity);
byte[] hitFlags = hitPool.Rent(batchCapacity);
var limiter = GpuPrimeWorkLimiter.Acquire();
var gpu = PrimeTester.PrimeTesterGpuContextPool.Rent();
var gpu = PrimeTester.PrimeTesterGpuContextPool.Rent(batchCapacity, 1);
var accelerator = gpu.Accelerator;
var state = PrimeTester.GpuKernelState.GetOrCreate(accelerator);
var scratch = state.RentScratch(batchCapacity, accelerator);
var state = gpu.State;
var scratch = gpu.Scratch;
bool compositeDetected = false;
int count = 0;
// lock (gpu.ExecutionLock)
var inputView = scratch.Input.View;
var outputView = scratch.Output.View;
bool ProcessBatch(int length)
{
var input = scratch.Input;
var output = scratch.Output;
inputView.CopyFromCPU(ref divisorArray[0], length);
byte compositeFlag = 0;
outputView.CopyFromCPU(ref compositeFlag, 1);
state.HeuristicTrialDivisionKernel(length, inputView, n, outputView);
accelerator.Synchronize();
outputView.CopyToCPU(ref compositeFlag, 1);
bool ProcessBatch(int length)
return compositeFlag != 0;
}
ReadOnlySpan<int> groupADivisors = HeuristicPrimeSieves.GroupADivisors;
int groupAIndex = 0;
ReadOnlySpan<byte> endingOrder = GetGroupBEndingOrder(nMod10);
Span<int> indices = endingOrder.Length <= 8
? stackalloc int[endingOrder.Length]
: new int[endingOrder.Length];
bool groupAHasMore = groupAIndex < groupADivisors.Length && (ulong)groupADivisors[groupAIndex] <= sqrtLimit;
bool groupBHasMore = !endingOrder.IsEmpty && HasGroupBCandidates(endingOrder, indices, sqrtLimit);
while (!compositeDetected && (groupAHasMore || groupBHasMore))
{
if (groupAHasMore)
{
if (length <= 0)
int processed = 0;
while (processed < interleaveBatchSize && groupAIndex < groupADivisors.Length)
{
return false;
}
input.View.CopyFromCPU(ref divisorArray[0], length);
state.HeuristicTrialDivisionKernel(length, input.View, n, output.View);
accelerator.Synchronize();
output.View.CopyToCPU(ref hitFlags[0], length);
for (int i = 0; i < length; i++)
{
if (hitFlags[i] == 0)
{
continue;
}
ulong divisor = divisorArray[i];
if (divisor > 1UL && n % divisor == 0UL)
{
return true;
}
}
return false;
}
ReadOnlySpan<int> groupADivisors = HeuristicPrimeSieves.GroupADivisors;
int groupAIndex = 0;
ReadOnlySpan<byte> endingOrder = GetGroupBEndingOrder(nMod10);
Span<int> indices = endingOrder.Length <= 8
? stackalloc int[endingOrder.Length]
: new int[endingOrder.Length];
bool groupAHasMore = groupAIndex < groupADivisors.Length && (ulong)groupADivisors[groupAIndex] <= sqrtLimit;
bool groupBHasMore = !endingOrder.IsEmpty && HasGroupBCandidates(endingOrder, indices, sqrtLimit);
while (!compositeDetected && (groupAHasMore || groupBHasMore))
{
if (groupAHasMore)
{
int processed = 0;
while (processed < interleaveBatchSize && groupAIndex < groupADivisors.Length)
{
ulong divisor = (ulong)groupADivisors[groupAIndex];
if (divisor > sqrtLimit)
{
groupAIndex = groupADivisors.Length;
groupAHasMore = false;
break;
}
divisorArray[count] = divisor;
count++;
if (count == batchCapacity)
{
if (ProcessBatch(count))
{
compositeDetected = true;
goto Cleanup;
}
count = 0;
}
groupAIndex++;
processed++;
}
if (groupAIndex >= groupADivisors.Length)
ulong divisor = (ulong)groupADivisors[groupAIndex];
if (divisor > sqrtLimit)
{
groupAIndex = groupADivisors.Length;
groupAHasMore = false;
break;
}
else
divisorArray[count] = divisor;
count++;
if (count == batchCapacity)
{
groupAHasMore = (ulong)groupADivisors[groupAIndex] <= sqrtLimit;
if (!groupAHasMore)
if (ProcessBatch(count))
{
groupAIndex = groupADivisors.Length;
compositeDetected = true;
goto Cleanup;
}
count = 0;
}
groupAIndex++;
processed++;
}
if (!compositeDetected && groupBHasMore)
if (groupAIndex >= groupADivisors.Length)
{
int processed = 0;
while (processed < interleaveBatchSize)
groupAHasMore = false;
}
else
{
groupAHasMore = (ulong)groupADivisors[groupAIndex] <= sqrtLimit;
if (!groupAHasMore)
{
if (!TrySelectNextGroupBDivisor(endingOrder, indices, sqrtLimit, out ulong divisor))
{
groupBHasMore = false;
break;
}
divisorArray[count] = divisor;
count++;
if (count == batchCapacity)
{
if (ProcessBatch(count))
{
compositeDetected = true;
goto Cleanup;
}
count = 0;
}
processed++;
}
if (groupBHasMore)
{
groupBHasMore = HasGroupBCandidates(endingOrder, indices, sqrtLimit);
groupAIndex = groupADivisors.Length;
}
}
}
if (!compositeDetected && count > 0)
if (!compositeDetected && groupBHasMore)
{
if (ProcessBatch(count))
int processed = 0;
while (processed < interleaveBatchSize)
{
compositeDetected = true;
goto Cleanup;
if (!TrySelectNextGroupBDivisor(endingOrder, indices, sqrtLimit, out ulong divisor))
{
groupBHasMore = false;
break;
}
divisorArray[count] = divisor;
count++;
if (count == batchCapacity)
{
if (ProcessBatch(count))
{
compositeDetected = true;
goto Cleanup;
}
count = 0;
}
processed++;
}
count = 0;
if (groupBHasMore)
{
groupBHasMore = HasGroupBCandidates(endingOrder, indices, sqrtLimit);
}
}
}
if (count > 0 && ProcessBatch(count))
{
compositeDetected = true;
goto Cleanup;
}
Cleanup:
state.ReturnScratch(scratch);
divisorPool.Return(divisorArray);
hitPool.Return(hitFlags);
gpu.Dispose();
limiter.Dispose();
return compositeDetected;
}
private static bool EvaluateWithOpenNumericFallback(ulong n)
{
return Prime.Numbers.IsPrime(n);