block_histogram.cuh

File members: /home/runner/work/cccl/cccl/cub/cub/block/block_histogram.cuh
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 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
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#pragma once

#include <cub/config.cuh>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cub/block/specializations/block_histogram_atomic.cuh>
#include <cub/block/specializations/block_histogram_sort.cuh>
#include <cub/util_ptx.cuh>

CUB_NAMESPACE_BEGIN

enum BlockHistogramAlgorithm
{

  BLOCK_HISTO_SORT,

  BLOCK_HISTO_ATOMIC,
};

template <typename T,
          int BLOCK_DIM_X,
          int ITEMS_PER_THREAD,
          int BINS,
          BlockHistogramAlgorithm ALGORITHM = BLOCK_HISTO_SORT,
          int BLOCK_DIM_Y                   = 1,
          int BLOCK_DIM_Z                   = 1,
          int LEGACY_PTX_ARCH               = 0>
class BlockHistogram
{
private:
  enum
  {
    BLOCK_THREADS = BLOCK_DIM_X * BLOCK_DIM_Y * BLOCK_DIM_Z,
  };

  using InternalBlockHistogram =
    cub::detail::conditional_t<ALGORITHM == BLOCK_HISTO_SORT,
                               BlockHistogramSort<T, BLOCK_DIM_X, ITEMS_PER_THREAD, BINS, BLOCK_DIM_Y, BLOCK_DIM_Z>,
                               BlockHistogramAtomic<BINS>>;

  using _TempStorage = typename InternalBlockHistogram::TempStorage;

  _TempStorage& temp_storage;

  unsigned int linear_tid;

  _CCCL_DEVICE _CCCL_FORCEINLINE _TempStorage& PrivateStorage()
  {
    __shared__ _TempStorage private_storage;
    return private_storage;
  }

public:
  struct TempStorage : Uninitialized<_TempStorage>
  {};

  _CCCL_DEVICE _CCCL_FORCEINLINE BlockHistogram()
      : temp_storage(PrivateStorage())
      , linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
  {}

  _CCCL_DEVICE _CCCL_FORCEINLINE BlockHistogram(TempStorage& temp_storage)
      : temp_storage(temp_storage.Alias())
      , linear_tid(RowMajorTid(BLOCK_DIM_X, BLOCK_DIM_Y, BLOCK_DIM_Z))
  {}

  template <typename CounterT>
  _CCCL_DEVICE _CCCL_FORCEINLINE void InitHistogram(CounterT histogram[BINS])
  {
    // Initialize histogram bin counts to zeros
    int histo_offset = 0;

#pragma unroll
    for (; histo_offset + BLOCK_THREADS <= BINS; histo_offset += BLOCK_THREADS)
    {
      histogram[histo_offset + linear_tid] = 0;
    }
    // Finish up with guarded initialization if necessary
    if ((BINS % BLOCK_THREADS != 0) && (histo_offset + linear_tid < BINS))
    {
      histogram[histo_offset + linear_tid] = 0;
    }
  }

  template <typename CounterT>
  _CCCL_DEVICE _CCCL_FORCEINLINE void Histogram(T (&items)[ITEMS_PER_THREAD], CounterT histogram[BINS])
  {
    // Initialize histogram bin counts to zeros
    InitHistogram(histogram);

    CTA_SYNC();

    // Composite the histogram
    InternalBlockHistogram(temp_storage).Composite(items, histogram);
  }

  template <typename CounterT>
  _CCCL_DEVICE _CCCL_FORCEINLINE void Composite(T (&items)[ITEMS_PER_THREAD], CounterT histogram[BINS])
  {
    InternalBlockHistogram(temp_storage).Composite(items, histogram);
  }
};

CUB_NAMESPACE_END