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+/******************************************************************************
+ * Copyright (c) 2011, Duane Merrill.  All rights reserved.
+ * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the NVIDIA CORPORATION nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************/
+
+/**
+ * \file
+ * The cub::WarpReduce class provides [<em>collective</em>](index.html#sec0) methods for computing a parallel reduction of items partitioned across a CUDA thread warp.
+ */
+
+#pragma once
+
+#include "specializations/warp_reduce_shfl.cuh"
+#include "specializations/warp_reduce_smem.cuh"
+#include "../thread/thread_operators.cuh"
+#include "../util_arch.cuh"
+#include "../util_type.cuh"
+#include "../util_namespace.cuh"
+
+/// Optional outer namespace(s)
+CUB_NS_PREFIX
+
+/// CUB namespace
+namespace cub {
+
+
+/**
+ * \addtogroup WarpModule
+ * @{
+ */
+
+/**
+ * \brief The WarpReduce class provides [<em>collective</em>](index.html#sec0) methods for computing a parallel reduction of items partitioned across a CUDA thread warp. ![](warp_reduce_logo.png)
+ *
+ * \tparam T                        The reduction input/output element type
+ * \tparam LOGICAL_WARP_THREADS     <b>[optional]</b> The number of threads per "logical" warp (may be less than the number of hardware warp threads).  Default is the warp size of the targeted CUDA compute-capability (e.g., 32 threads for SM20).
+ * \tparam PTX_ARCH                 <b>[optional]</b> \ptxversion
+ *
+ * \par Overview
+ * - A <a href="http://en.wikipedia.org/wiki/Reduce_(higher-order_function)"><em>reduction</em></a> (or <em>fold</em>)
+ *   uses a binary combining operator to compute a single aggregate from a list of input elements.
+ * - Supports "logical" warps smaller than the physical warp size (e.g., logical warps of 8 threads)
+ * - The number of entrant threads must be an multiple of \p LOGICAL_WARP_THREADS
+ *
+ * \par Performance Considerations
+ * - Uses special instructions when applicable (e.g., warp \p SHFL instructions)
+ * - Uses synchronization-free communication between warp lanes when applicable
+ * - Incurs zero bank conflicts for most types
+ * - Computation is slightly more efficient (i.e., having lower instruction overhead) for:
+ *     - Summation (<b><em>vs.</em></b> generic reduction)
+ *     - The architecture's warp size is a whole multiple of \p LOGICAL_WARP_THREADS
+ *
+ * \par Simple Examples
+ * \warpcollective{WarpReduce}
+ * \par
+ * The code snippet below illustrates four concurrent warp sum reductions within a block of
+ * 128 threads (one per each of the 32-thread warps).
+ * \par
+ * \code
+ * #include <cub/cub.cuh>
+ *
+ * __global__ void ExampleKernel(...)
+ * {
+ *     // Specialize WarpReduce for type int
+ *     typedef cub::WarpReduce<int> WarpReduce;
+ *
+ *     // Allocate WarpReduce shared memory for 4 warps
+ *     __shared__ typename WarpReduce::TempStorage temp_storage[4];
+ *
+ *     // Obtain one input item per thread
+ *     int thread_data = ...
+ *
+ *     // Return the warp-wide sums to each lane0 (threads 0, 32, 64, and 96)
+ *     int warp_id = threadIdx.x / 32;
+ *     int aggregate = WarpReduce(temp_storage[warp_id]).Sum(thread_data);
+ *
+ * \endcode
+ * \par
+ * Suppose the set of input \p thread_data across the block of threads is <tt>{0, 1, 2, 3, ..., 127}</tt>.
+ * The corresponding output \p aggregate in threads 0, 32, 64, and 96 will \p 496, \p 1520,
+ * \p 2544, and \p 3568, respectively (and is undefined in other threads).
+ *
+ * \par
+ * The code snippet below illustrates a single warp sum reduction within a block of
+ * 128 threads.
+ * \par
+ * \code
+ * #include <cub/cub.cuh>
+ *
+ * __global__ void ExampleKernel(...)
+ * {
+ *     // Specialize WarpReduce for type int
+ *     typedef cub::WarpReduce<int> WarpReduce;
+ *
+ *     // Allocate WarpReduce shared memory for one warp
+ *     __shared__ typename WarpReduce::TempStorage temp_storage;
+ *     ...
+ *
+ *     // Only the first warp performs a reduction
+ *     if (threadIdx.x < 32)
+ *     {
+ *         // Obtain one input item per thread
+ *         int thread_data = ...
+ *
+ *         // Return the warp-wide sum to lane0
+ *         int aggregate = WarpReduce(temp_storage).Sum(thread_data);
+ *
+ * \endcode
+ * \par
+ * Suppose the set of input \p thread_data across the warp of threads is <tt>{0, 1, 2, 3, ..., 31}</tt>.
+ * The corresponding output \p aggregate in thread0 will be \p 496 (and is undefined in other threads).
+ *
+ */
+template <
+    typename    T,
+    int         LOGICAL_WARP_THREADS    = CUB_PTX_WARP_THREADS,
+    int         PTX_ARCH                = CUB_PTX_ARCH>
+class WarpReduce
+{
+private:
+
+    /******************************************************************************
+     * Constants and type definitions
+     ******************************************************************************/
+
+    enum
+    {
+        /// Whether the logical warp size and the PTX warp size coincide
+        IS_ARCH_WARP = (LOGICAL_WARP_THREADS == CUB_WARP_THREADS(PTX_ARCH)),
+
+        /// Whether the logical warp size is a power-of-two
+        IS_POW_OF_TWO = PowerOfTwo<LOGICAL_WARP_THREADS>::VALUE,
+    };
+
+public:
+
+    #ifndef DOXYGEN_SHOULD_SKIP_THIS    // Do not document
+
+    /// Internal specialization.  Use SHFL-based reduction if (architecture is >= SM30) and (LOGICAL_WARP_THREADS is a power-of-two)
+    typedef typename If<(PTX_ARCH >= 300) && (IS_POW_OF_TWO),
+        WarpReduceShfl<T, LOGICAL_WARP_THREADS, PTX_ARCH>,
+        WarpReduceSmem<T, LOGICAL_WARP_THREADS, PTX_ARCH> >::Type InternalWarpReduce;
+
+    #endif // DOXYGEN_SHOULD_SKIP_THIS
+
+
+private:
+
+    /// Shared memory storage layout type for WarpReduce
+    typedef typename InternalWarpReduce::TempStorage _TempStorage;
+
+
+    /******************************************************************************
+     * Thread fields
+     ******************************************************************************/
+
+    /// Shared storage reference
+    _TempStorage &temp_storage;
+
+
+    /******************************************************************************
+     * Utility methods
+     ******************************************************************************/
+
+public:
+
+    /// \smemstorage{WarpReduce}
+    struct TempStorage : Uninitialized<_TempStorage> {};
+
+
+    /******************************************************************//**
+     * \name Collective constructors
+     *********************************************************************/
+    //@{
+
+
+    /**
+     * \brief Collective constructor using the specified memory allocation as temporary storage.  Logical warp and lane identifiers are constructed from <tt>threadIdx.x</tt>.
+     */
+    __device__ __forceinline__ WarpReduce(
+        TempStorage &temp_storage)             ///< [in] Reference to memory allocation having layout type TempStorage
+    :
+        temp_storage(temp_storage.Alias())
+    {}
+
+
+    //@}  end member group
+    /******************************************************************//**
+     * \name Summation reductions
+     *********************************************************************/
+    //@{
+
+
+    /**
+     * \brief Computes a warp-wide sum in the calling warp.  The output is valid in warp <em>lane</em><sub>0</sub>.
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates four concurrent warp sum reductions within a block of
+     * 128 threads (one per each of the 32-thread warps).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for 4 warps
+     *     __shared__ typename WarpReduce::TempStorage temp_storage[4];
+     *
+     *     // Obtain one input item per thread
+     *     int thread_data = ...
+     *
+     *     // Return the warp-wide sums to each lane0
+     *     int warp_id = threadIdx.x / 32;
+     *     int aggregate = WarpReduce(temp_storage[warp_id]).Sum(thread_data);
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data across the block of threads is <tt>{0, 1, 2, 3, ..., 127}</tt>.
+     * The corresponding output \p aggregate in threads 0, 32, 64, and 96 will \p 496, \p 1520,
+     * \p 2544, and \p 3568, respectively (and is undefined in other threads).
+     *
+     */
+    __device__ __forceinline__ T Sum(
+        T                   input)              ///< [in] Calling thread's input
+    {
+        return InternalWarpReduce(temp_storage).template Reduce<true>(input, LOGICAL_WARP_THREADS, cub::Sum());
+    }
+
+    /**
+     * \brief Computes a partially-full warp-wide sum in the calling warp.  The output is valid in warp <em>lane</em><sub>0</sub>.
+     *
+     * All threads across the calling warp must agree on the same value for \p valid_items.  Otherwise the result is undefined.
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a sum reduction within a single, partially-full
+     * block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(int *d_data, int valid_items)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item per thread if in range
+     *     int thread_data;
+     *     if (threadIdx.x < valid_items)
+     *         thread_data = d_data[threadIdx.x];
+     *
+     *     // Return the warp-wide sums to each lane0
+     *     int aggregate = WarpReduce(temp_storage).Sum(
+     *         thread_data, valid_items);
+     *
+     * \endcode
+     * \par
+     * Suppose the input \p d_data is <tt>{0, 1, 2, 3, 4, ...</tt> and \p valid_items
+     * is \p 4.  The corresponding output \p aggregate in thread0 is \p 6 (and is
+     * undefined in other threads).
+     *
+     */
+    __device__ __forceinline__ T Sum(
+        T                   input,              ///< [in] Calling thread's input
+        int                 valid_items)        ///< [in] Total number of valid items in the calling thread's logical warp (may be less than \p LOGICAL_WARP_THREADS)
+    {
+        // Determine if we don't need bounds checking
+        return InternalWarpReduce(temp_storage).template Reduce<false>(input, valid_items, cub::Sum());
+    }
+
+
+    /**
+     * \brief Computes a segmented sum in the calling warp where segments are defined by head-flags.  The sum of each segment is returned to the first lane in that segment (which always includes <em>lane</em><sub>0</sub>).
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a head-segmented warp sum
+     * reduction within a block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item and flag per thread
+     *     int thread_data = ...
+     *     int head_flag = ...
+     *
+     *     // Return the warp-wide sums to each lane0
+     *     int aggregate = WarpReduce(temp_storage).HeadSegmentedSum(
+     *         thread_data, head_flag);
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data and \p head_flag across the block of threads
+     * is <tt>{0, 1, 2, 3, ..., 31</tt> and is <tt>{1, 0, 0, 0, 1, 0, 0, 0, ..., 1, 0, 0, 0</tt>,
+     * respectively.  The corresponding output \p aggregate in threads 0, 4, 8, etc. will be
+     * \p 6, \p 22, \p 38, etc. (and is undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     *
+     */
+    template <
+        typename            FlagT>
+    __device__ __forceinline__ T HeadSegmentedSum(
+        T                   input,              ///< [in] Calling thread's input
+        FlagT                head_flag)          ///< [in] Head flag denoting whether or not \p input is the start of a new segment
+    {
+        return HeadSegmentedReduce(input, head_flag, cub::Sum());
+    }
+
+
+    /**
+     * \brief Computes a segmented sum in the calling warp where segments are defined by tail-flags.  The sum of each segment is returned to the first lane in that segment (which always includes <em>lane</em><sub>0</sub>).
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a tail-segmented warp sum
+     * reduction within a block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item and flag per thread
+     *     int thread_data = ...
+     *     int tail_flag = ...
+     *
+     *     // Return the warp-wide sums to each lane0
+     *     int aggregate = WarpReduce(temp_storage).TailSegmentedSum(
+     *         thread_data, tail_flag);
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data and \p tail_flag across the block of threads
+     * is <tt>{0, 1, 2, 3, ..., 31</tt> and is <tt>{0, 0, 0, 1, 0, 0, 0, 1, ..., 0, 0, 0, 1</tt>,
+     * respectively.  The corresponding output \p aggregate in threads 0, 4, 8, etc. will be
+     * \p 6, \p 22, \p 38, etc. (and is undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     */
+    template <
+        typename            FlagT>
+    __device__ __forceinline__ T TailSegmentedSum(
+        T                   input,              ///< [in] Calling thread's input
+        FlagT                tail_flag)          ///< [in] Head flag denoting whether or not \p input is the start of a new segment
+    {
+        return TailSegmentedReduce(input, tail_flag, cub::Sum());
+    }
+
+
+
+    //@}  end member group
+    /******************************************************************//**
+     * \name Generic reductions
+     *********************************************************************/
+    //@{
+
+    /**
+     * \brief Computes a warp-wide reduction in the calling warp using the specified binary reduction functor.  The output is valid in warp <em>lane</em><sub>0</sub>.
+     *
+     * Supports non-commutative reduction operators
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates four concurrent warp max reductions within a block of
+     * 128 threads (one per each of the 32-thread warps).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for 4 warps
+     *     __shared__ typename WarpReduce::TempStorage temp_storage[4];
+     *
+     *     // Obtain one input item per thread
+     *     int thread_data = ...
+     *
+     *     // Return the warp-wide reductions to each lane0
+     *     int warp_id = threadIdx.x / 32;
+     *     int aggregate = WarpReduce(temp_storage[warp_id]).Reduce(
+     *         thread_data, cub::Max());
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data across the block of threads is <tt>{0, 1, 2, 3, ..., 127}</tt>.
+     * The corresponding output \p aggregate in threads 0, 32, 64, and 96 will \p 31, \p 63,
+     * \p 95, and \p 127, respectively  (and is undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     */
+    template <typename ReductionOp>
+    __device__ __forceinline__ T Reduce(
+        T                   input,              ///< [in] Calling thread's input
+        ReductionOp         reduction_op)       ///< [in] Binary reduction operator
+    {
+        return InternalWarpReduce(temp_storage).template Reduce<true>(input, LOGICAL_WARP_THREADS, reduction_op);
+    }
+
+    /**
+     * \brief Computes a partially-full warp-wide reduction in the calling warp using the specified binary reduction functor.  The output is valid in warp <em>lane</em><sub>0</sub>.
+     *
+     * All threads across the calling warp must agree on the same value for \p valid_items.  Otherwise the result is undefined.
+     *
+     * Supports non-commutative reduction operators
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a max reduction within a single, partially-full
+     * block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(int *d_data, int valid_items)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item per thread if in range
+     *     int thread_data;
+     *     if (threadIdx.x < valid_items)
+     *         thread_data = d_data[threadIdx.x];
+     *
+     *     // Return the warp-wide reductions to each lane0
+     *     int aggregate = WarpReduce(temp_storage).Reduce(
+     *         thread_data, cub::Max(), valid_items);
+     *
+     * \endcode
+     * \par
+     * Suppose the input \p d_data is <tt>{0, 1, 2, 3, 4, ...</tt> and \p valid_items
+     * is \p 4.  The corresponding output \p aggregate in thread0 is \p 3 (and is
+     * undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     */
+    template <typename ReductionOp>
+    __device__ __forceinline__ T Reduce(
+        T                   input,              ///< [in] Calling thread's input
+        ReductionOp         reduction_op,       ///< [in] Binary reduction operator
+        int                 valid_items)        ///< [in] Total number of valid items in the calling thread's logical warp (may be less than \p LOGICAL_WARP_THREADS)
+    {
+        return InternalWarpReduce(temp_storage).template Reduce<false>(input, valid_items, reduction_op);
+    }
+
+
+    /**
+     * \brief Computes a segmented reduction in the calling warp where segments are defined by head-flags.  The reduction of each segment is returned to the first lane in that segment (which always includes <em>lane</em><sub>0</sub>).
+     *
+     * Supports non-commutative reduction operators
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a head-segmented warp max
+     * reduction within a block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item and flag per thread
+     *     int thread_data = ...
+     *     int head_flag = ...
+     *
+     *     // Return the warp-wide reductions to each lane0
+     *     int aggregate = WarpReduce(temp_storage).HeadSegmentedReduce(
+     *         thread_data, head_flag, cub::Max());
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data and \p head_flag across the block of threads
+     * is <tt>{0, 1, 2, 3, ..., 31</tt> and is <tt>{1, 0, 0, 0, 1, 0, 0, 0, ..., 1, 0, 0, 0</tt>,
+     * respectively.  The corresponding output \p aggregate in threads 0, 4, 8, etc. will be
+     * \p 3, \p 7, \p 11, etc. (and is undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     */
+    template <
+        typename            ReductionOp,
+        typename            FlagT>
+    __device__ __forceinline__ T HeadSegmentedReduce(
+        T                   input,              ///< [in] Calling thread's input
+        FlagT               head_flag,          ///< [in] Head flag denoting whether or not \p input is the start of a new segment
+        ReductionOp         reduction_op)       ///< [in] Reduction operator
+    {
+        return InternalWarpReduce(temp_storage).template SegmentedReduce<true>(input, head_flag, reduction_op);
+    }
+
+
+    /**
+     * \brief Computes a segmented reduction in the calling warp where segments are defined by tail-flags.  The reduction of each segment is returned to the first lane in that segment (which always includes <em>lane</em><sub>0</sub>).
+     *
+     * Supports non-commutative reduction operators
+     *
+     * \smemreuse
+     *
+     * \par Snippet
+     * The code snippet below illustrates a tail-segmented warp max
+     * reduction within a block of 32 threads (one warp).
+     * \par
+     * \code
+     * #include <cub/cub.cuh>
+     *
+     * __global__ void ExampleKernel(...)
+     * {
+     *     // Specialize WarpReduce for type int
+     *     typedef cub::WarpReduce<int> WarpReduce;
+     *
+     *     // Allocate WarpReduce shared memory for one warp
+     *     __shared__ typename WarpReduce::TempStorage temp_storage;
+     *
+     *     // Obtain one input item and flag per thread
+     *     int thread_data = ...
+     *     int tail_flag = ...
+     *
+     *     // Return the warp-wide reductions to each lane0
+     *     int aggregate = WarpReduce(temp_storage).TailSegmentedReduce(
+     *         thread_data, tail_flag, cub::Max());
+     *
+     * \endcode
+     * \par
+     * Suppose the set of input \p thread_data and \p tail_flag across the block of threads
+     * is <tt>{0, 1, 2, 3, ..., 31</tt> and is <tt>{0, 0, 0, 1, 0, 0, 0, 1, ..., 0, 0, 0, 1</tt>,
+     * respectively.  The corresponding output \p aggregate in threads 0, 4, 8, etc. will be
+     * \p 3, \p 7, \p 11, etc. (and is undefined in other threads).
+     *
+     * \tparam ReductionOp     <b>[inferred]</b> Binary reduction operator type having member <tt>T operator()(const T &a, const T &b)</tt>
+     */
+    template <
+        typename            ReductionOp,
+        typename            FlagT>
+    __device__ __forceinline__ T TailSegmentedReduce(
+        T                   input,              ///< [in] Calling thread's input
+        FlagT               tail_flag,          ///< [in] Tail flag denoting whether or not \p input is the end of the current segment
+        ReductionOp         reduction_op)       ///< [in] Reduction operator
+    {
+        return InternalWarpReduce(temp_storage).template SegmentedReduce<false>(input, tail_flag, reduction_op);
+    }
+
+
+
+    //@}  end member group
+};
+
+/** @} */       // end group WarpModule
+
+}               // CUB namespace
+CUB_NS_POSTFIX  // Optional outer namespace(s)