warp_scan.cuh

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#ifndef HIPCUB_ROCPRIM_WARP_WARP_SCAN_HPP_
#define HIPCUB_ROCPRIM_WARP_WARP_SCAN_HPP_

#include "../config.hpp"

#include "../util_ptx.cuh"
#include "../thread/thread_operators.cuh"

#include <cub/rocprim/warp/warp_scan.hpp>

BEGIN_HIPCUB_NAMESPACE

template<
    typename T,
    int LOGICAL_WARP_THREADS = HIPCUB_DEVICE_WARP_THREADS,
    int ARCH = HIPCUB_ARCH>
class WarpScan : private ::rocprim::warp_scan<T, LOGICAL_WARP_THREADS>
{
    static_assert(LOGICAL_WARP_THREADS > 0, "LOGICAL_WARP_THREADS must be greater than 0");
    using base_type = typename ::rocprim::warp_scan<T, LOGICAL_WARP_THREADS>;

    typename base_type::storage_type &temp_storage_;

public:
    using TempStorage = typename base_type::storage_type;

    HIPCUB_DEVICE inline
    WarpScan(TempStorage& temp_storage) : temp_storage_(temp_storage)
    {
    }

    HIPCUB_DEVICE inline
    void InclusiveSum(T input, T& inclusive_output)
    {
        base_type::inclusive_scan(input, inclusive_output, temp_storage_);
    }

    HIPCUB_DEVICE inline
    void InclusiveSum(T input, T& inclusive_output, T& warp_aggregate)
    {
        base_type::inclusive_scan(input, inclusive_output, warp_aggregate, temp_storage_);
    }

    HIPCUB_DEVICE inline
    void ExclusiveSum(T input, T& exclusive_output)
    {
        base_type::exclusive_scan(input, exclusive_output, T(0), temp_storage_);
    }

    HIPCUB_DEVICE inline
    void ExclusiveSum(T input, T& exclusive_output, T& warp_aggregate)
    {
        base_type::exclusive_scan(input, exclusive_output, T(0), warp_aggregate, temp_storage_);
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void InclusiveScan(T input, T& inclusive_output, ScanOp scan_op)
    {
        base_type::inclusive_scan(input, inclusive_output, temp_storage_, scan_op);
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void InclusiveScan(T input, T& inclusive_output, ScanOp scan_op, T& warp_aggregate)
    {
        base_type::inclusive_scan(
            input, inclusive_output, warp_aggregate,
            temp_storage_, scan_op
        );
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void ExclusiveScan(T input, T& exclusive_output, ScanOp scan_op)
    {
        base_type::inclusive_scan(input, exclusive_output, temp_storage_, scan_op);
        base_type::to_exclusive(exclusive_output, exclusive_output, temp_storage_);
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void ExclusiveScan(T input, T& exclusive_output, T initial_value, ScanOp scan_op)
    {
        base_type::exclusive_scan(
            input, exclusive_output, initial_value,
            temp_storage_, scan_op
        );
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void ExclusiveScan(T input, T& exclusive_output, ScanOp scan_op, T& warp_aggregate)
    {
        base_type::inclusive_scan(
            input, exclusive_output, warp_aggregate, temp_storage_, scan_op
        );
        base_type::to_exclusive(exclusive_output, exclusive_output, temp_storage_);
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void ExclusiveScan(T input, T& exclusive_output, T initial_value, ScanOp scan_op, T& warp_aggregate)
    {
        base_type::exclusive_scan(
            input, exclusive_output, initial_value, warp_aggregate,
            temp_storage_, scan_op
        );
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void Scan(T input, T& inclusive_output, T& exclusive_output, ScanOp scan_op)
    {
        base_type::inclusive_scan(input, inclusive_output, temp_storage_, scan_op);
        base_type::to_exclusive(inclusive_output, exclusive_output, temp_storage_);
    }

    template<typename ScanOp>
    HIPCUB_DEVICE inline
    void Scan(T input, T& inclusive_output, T& exclusive_output, T initial_value, ScanOp scan_op)
    {
        base_type::scan(
            input, inclusive_output, exclusive_output, initial_value,
            temp_storage_, scan_op
        );
        // In CUB documentation it's unclear if inclusive_output should include initial_value,
        // however,the implementation includes initial_value in inclusive_output in WarpScan::Scan().
        // In rocPRIM it's not included, and this is a fix to match CUB implementation.
        // After confirmation from CUB's developers we will most probably change rocPRIM too.
        inclusive_output = scan_op(initial_value, inclusive_output);
    }

    HIPCUB_DEVICE inline
    T Broadcast(T input, unsigned int src_lane)
    {
        return base_type::broadcast(input, src_lane, temp_storage_);
    }
};

END_HIPCUB_NAMESPACE

#endif // HIPCUB_ROCPRIM_WARP_WARP_SCAN_HPP_