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/**
 * \file
 * The cub::BlockDiscontinuity class provides [<em>collective</em>](index.html#sec0) methods for flagging discontinuities within an ordered set of items partitioned across a CUDA thread block.
 */

#pragma once

#include "../util_type.cuh"
#include "../util_ptx.cuh"
#include "../util_namespace.cuh"

/// Optional outer namespace(s)
CUB_NS_PREFIX

/// CUB namespace
namespace cub {

/**
 * \brief The BlockDiscontinuity class provides [<em>collective</em>](index.html#sec0) methods for flagging discontinuities within an ordered set of items partitioned across a CUDA thread block. ![](discont_logo.png)
 * \ingroup BlockModule
 *
 * \tparam T                The data type to be flagged.
 * \tparam BLOCK_DIM_X      The thread block length in threads along the X dimension
 * \tparam BLOCK_DIM_Y      <b>[optional]</b> The thread block length in threads along the Y dimension (default: 1)
 * \tparam BLOCK_DIM_Z      <b>[optional]</b> The thread block length in threads along the Z dimension (default: 1)
 * \tparam PTX_ARCH         <b>[optional]</b> \ptxversion
 *
 * \par Overview
 * - A set of "head flags" (or "tail flags") is often used to indicate corresponding items
 *   that differ from their predecessors (or successors).  For example, head flags are convenient
 *   for demarcating disjoint data segments as part of a segmented scan or reduction.
 * - \blocked
 *
 * \par Performance Considerations
 * - \granularity
 *
 * \par A Simple Example
 * \blockcollective{BlockDiscontinuity}
 * \par
 * The code snippet below illustrates the head flagging of 512 integer items that
 * are partitioned in a [<em>blocked arrangement</em>](index.html#sec5sec3) across 128 threads
 * where each thread owns 4 consecutive items.
 * \par
 * \code
 * #include <cub/cub.cuh>   // or equivalently <cub/block/block_discontinuity.cuh>
 *
 * __global__ void ExampleKernel(...)
 * {
 *     // Specialize BlockDiscontinuity for a 1D block of 128 threads on type int
 *     typedef cub::BlockDiscontinuity<int, 128> BlockDiscontinuity;
 *
 *     // Allocate shared memory for BlockDiscontinuity
 *     __shared__ typename BlockDiscontinuity::TempStorage temp_storage;
 *
 *     // Obtain a segment of consecutive items that are blocked across threads
 *     int thread_data[4];
 *     ...
 *
 *     // Collectively compute head flags for discontinuities in the segment
 *     int head_flags[4];
 *     BlockDiscontinuity(temp_storage).FlagHeads(head_flags, thread_data, cub::Inequality());
 *
 * \endcode
 * \par
 * Suppose the set of input \p thread_data across the block of threads is
 * <tt>{ [0,0,1,1], [1,1,1,1], [2,3,3,3], [3,4,4,4], ... }</tt>.
 * The corresponding output \p head_flags in those threads will be
 * <tt>{ [1,0,1,0], [0,0,0,0], [1,1,0,0], [0,1,0,0], ... }</tt>.
 *
 * \par Performance Considerations
 * - Incurs zero bank conflicts for most types
 *
 */
template <
    typename    T,
    int         BLOCK_DIM_X,
    int         BLOCK_DIM_Y     = 1,
    int         BLOCK_DIM_Z     = 1,
    int         PTX_ARCH        = CUB_PTX_ARCH>