/// <summary>
/// Computes the required number of temp-storage elements for a radix sort
/// operation and the given data length.
/// </summary>
/// <typeparam name="T">The underlying type of the sort operation.</typeparam>
/// <typeparam name="TRadixSortOperation">
/// The type of the radix-sort operation.
/// </typeparam>
/// <param name="accelerator">The accelerator.</param>
/// <param name="dataLength">The number of data elements to sort.</param>
/// <returns>
/// The required number of temp-storage elements in 32 bit ints.
/// </returns>
public static Index1 ComputeRadixSortTempStorageSize <T, TRadixSortOperation>(
this Accelerator accelerator,
Index1 dataLength)
where T : unmanaged
where TRadixSortOperation : struct, IRadixSortOperation <T>
{
Index1 tempScanMemory = accelerator.ComputeScanTempStorageSize <T>(dataLength);
int numGroups;
if (accelerator.AcceleratorType == AcceleratorType.CPU)
{
numGroups = accelerator.MaxNumThreads;
}
else
{
var(gridDim, _) = accelerator.ComputeGridStrideLoopExtent(
dataLength,
out int numIterationsPerGroup);
numGroups = gridDim * numIterationsPerGroup;
}
int numIntTElements = Interop.ComputeRelativeSizeOf <int, T>(dataLength);
const int unrollFactor = 4;
return(numGroups * unrollFactor * 2 + numIntTElements + tempScanMemory);
}
private ArrayView <int> AllocateTempScanView <T>(ArrayView <T> input)
where T : unmanaged
{
var tempSize = Accelerator.ComputeScanTempStorageSize <T>(input.Length);
return(bufferCache.Allocate <int>(tempSize));
}
private ArrayView <int> AllocateTempScanView <T>(ArrayView <T> input)
where T : unmanaged
{
var tempSize = Accelerator.ComputeScanTempStorageSize <T>(input.Length);
IndexTypeExtensions.AssertIntIndexRange(tempSize);
return(bufferCache.Allocate <int>(tempSize.ToIntIndex()));
}
private ArrayView <T> AllocateTempScanView <T>(ArrayView <T> input)
where T : struct
{
var tempSize = Accelerator.ComputeScanTempStorageSize(input.Length);
if (tempSize < 1)
{
throw new ArgumentOutOfRangeException(nameof(input));
}
return(bufferCache.Allocate <T>(tempSize));
}
