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#include "opencv2/gpu/device/vecmath.hpp"
#include "opencv2/gpu/device/transform.hpp"
#include "opencv2/gpu/device/limits_gpu.hpp"
#include "opencv2/gpu/device/saturate_cast.hpp"
#include "internal_shared.hpp"

using namespace cv::gpu;
using namespace cv::gpu::device;

namespace cv { namespace gpu { namespace mathfunc
{

    //////////////////////////////////////////////////////////////////////////////////////
    // Compare

    template <typename T1, typename T2>
    struct NotEqual
    {
        __device__ __forceinline__ uchar operator()(const T1& src1, const T2& src2)
        {
            return static_cast<uchar>(static_cast<int>(src1 != src2) * 255);
        }
    };

    template <typename T1, typename T2>
    inline void compare_ne(const DevMem2D& src1, const DevMem2D& src2, const DevMem2D& dst, cudaStream_t stream)
    {
        NotEqual<T1, T2> op;
        transform(static_cast< DevMem2D_<T1> >(src1), static_cast< DevMem2D_<T2> >(src2), dst, op, stream);
    }

    void compare_ne_8uc4(const DevMem2D& src1, const DevMem2D& src2, const DevMem2D& dst, cudaStream_t stream)
    {
        compare_ne<uint, uint>(src1, src2, dst, stream);
    }
    void compare_ne_32f(const DevMem2D& src1, const DevMem2D& src2, const DevMem2D& dst, cudaStream_t stream)
    {
        compare_ne<float, float>(src1, src2, dst, stream);
    }


    //////////////////////////////////////////////////////////////////////////
    // Unary bitwise logical matrix operations

    enum { UN_OP_NOT };

    template <typename T, int opid>
    struct UnOp;

    template <typename T>
    struct UnOp<T, UN_OP_NOT>
    { 
        static __device__ __forceinline__ T call(T v) { return ~v; }
    };


    template <int opid>
    __global__ void bitwiseUnOpKernel(int rows, int width, const PtrStep src, PtrStep dst)
    {
        const int x = (blockDim.x * blockIdx.x + threadIdx.x) * 4;
        const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (y < rows) 
        {
            uchar* dst_ptr = dst.ptr(y) + x;
            const uchar* src_ptr = src.ptr(y) + x;
            if (x + sizeof(uint) - 1 < width)
            {
                *(uint*)dst_ptr = UnOp<uint, opid>::call(*(uint*)src_ptr);
            }
            else
            {
                const uchar* src_end = src.ptr(y) + width;
                while (src_ptr < src_end)
                {
                    *dst_ptr++ = UnOp<uchar, opid>::call(*src_ptr++);
                }
            }
        }
    }


    template <int opid>
    void bitwiseUnOp(int rows, int width, const PtrStep src, PtrStep dst, 
                     cudaStream_t stream)
    {
        dim3 threads(16, 16);
        dim3 grid(divUp(width, threads.x * sizeof(uint)), 
                  divUp(rows, threads.y));

        bitwiseUnOpKernel<opid><<<grid, threads>>>(rows, width, src, dst);
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0) 
            cudaSafeCall( cudaDeviceSynchronize() );
    }


    template <typename T, int opid>
    __global__ void bitwiseUnOpKernel(int rows, int cols, int cn, const PtrStep src, 
                                      const PtrStep mask, PtrStep dst)
    {
        const int x = blockDim.x * blockIdx.x + threadIdx.x;
        const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (x < cols && y < rows && mask.ptr(y)[x / cn]) 
        {
            T* dst_row = (T*)dst.ptr(y);
            const T* src_row = (const T*)src.ptr(y);

            dst_row[x] = UnOp<T, opid>::call(src_row[x]);
        }
    }


    template <typename T, int opid>
    void bitwiseUnOp(int rows, int cols, int cn, const PtrStep src, 
                     const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        dim3 threads(16, 16);
        dim3 grid(divUp(cols, threads.x), divUp(rows, threads.y));

        bitwiseUnOpKernel<T, opid><<<grid, threads>>>(rows, cols, cn, src, mask, dst); 
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0) 
            cudaSafeCall( cudaDeviceSynchronize() );
    }


    void bitwiseNotCaller(int rows, int cols, int elem_size1, int cn, 
                          const PtrStep src, PtrStep dst, cudaStream_t stream)
    {
        bitwiseUnOp<UN_OP_NOT>(rows, cols * elem_size1 * cn, src, dst, stream);
    }


    template <typename T>
    void bitwiseMaskNotCaller(int rows, int cols, int cn, const PtrStep src, 
                              const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        bitwiseUnOp<T, UN_OP_NOT>(rows, cols * cn, cn, src, mask, dst, stream);
    }

    template void bitwiseMaskNotCaller<uchar>(int, int, int, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskNotCaller<ushort>(int, int, int, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskNotCaller<uint>(int, int, int, const PtrStep, const PtrStep, PtrStep, cudaStream_t);


    //////////////////////////////////////////////////////////////////////////
    // Binary bitwise logical matrix operations

    enum { BIN_OP_OR, BIN_OP_AND, BIN_OP_XOR };

    template <typename T, int opid>
    struct BinOp;

    template <typename T>
    struct BinOp<T, BIN_OP_OR>
    { 
        static __device__ __forceinline__ T call(T a, T b) { return a | b; } 
    };


    template <typename T>
    struct BinOp<T, BIN_OP_AND>
    { 
        static __device__ __forceinline__ T call(T a, T b) { return a & b; } 
    };

    template <typename T>
    struct BinOp<T, BIN_OP_XOR>
    { 
        static __device__ __forceinline__ T call(T a, T b) { return a ^ b; } 
    };


    template <int opid>
    __global__ void bitwiseBinOpKernel(int rows, int width, const PtrStep src1, 
                                       const PtrStep src2, PtrStep dst)
    {
        const int x = (blockDim.x * blockIdx.x + threadIdx.x) * 4;
        const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (y < rows) 
        {
            uchar* dst_ptr = dst.ptr(y) + x;
            const uchar* src1_ptr = src1.ptr(y) + x;
            const uchar* src2_ptr = src2.ptr(y) + x;

            if (x + sizeof(uint) - 1 < width)
            {
                *(uint*)dst_ptr = BinOp<uint, opid>::call(*(uint*)src1_ptr, *(uint*)src2_ptr);
            }
            else
            {
                const uchar* src1_end = src1.ptr(y) + width;
                while (src1_ptr < src1_end)
                {
                    *dst_ptr++ = BinOp<uchar, opid>::call(*src1_ptr++, *src2_ptr++);
                }
            }
        }
    }


    template <int opid>
    void bitwiseBinOp(int rows, int width, const PtrStep src1, const PtrStep src2, 
                      PtrStep dst, cudaStream_t stream)
    {
        dim3 threads(16, 16);
        dim3 grid(divUp(width, threads.x * sizeof(uint)), divUp(rows, threads.y));

        bitwiseBinOpKernel<opid><<<grid, threads>>>(rows, width, src1, src2, dst);
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0) 
            cudaSafeCall( cudaDeviceSynchronize() );
    }


    template <typename T, int opid>
    __global__ void bitwiseBinOpKernel(
            int rows, int cols, int cn, const PtrStep src1, const PtrStep src2, 
            const PtrStep mask, PtrStep dst)
    {
        const int x = blockDim.x * blockIdx.x + threadIdx.x;
        const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (x < cols && y < rows && mask.ptr(y)[x / cn]) 
        {
            T* dst_row = (T*)dst.ptr(y);
            const T* src1_row = (const T*)src1.ptr(y);
            const T* src2_row = (const T*)src2.ptr(y);

            dst_row[x] = BinOp<T, opid>::call(src1_row[x], src2_row[x]);
        }
    }


    template <typename T, int opid>
    void bitwiseBinOp(int rows, int cols, int cn, const PtrStep src1, const PtrStep src2, 
                        const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        dim3 threads(16, 16);
        dim3 grid(divUp(cols, threads.x), divUp(rows, threads.y));

        bitwiseBinOpKernel<T, opid><<<grid, threads>>>(rows, cols, cn, src1, src2, mask, dst);
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0) 
            cudaSafeCall( cudaDeviceSynchronize() );
    }


    void bitwiseOrCaller(int rows, int cols, int elem_size1, int cn, const PtrStep src1, 
                         const PtrStep src2, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<BIN_OP_OR>(rows, cols * elem_size1 * cn, src1, src2, dst, stream);
    }


    template <typename T>
    void bitwiseMaskOrCaller(int rows, int cols, int cn, const PtrStep src1, const PtrStep src2, 
                             const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<T, BIN_OP_OR>(rows, cols * cn, cn, src1, src2, mask, dst, stream);
    }

    template void bitwiseMaskOrCaller<uchar>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskOrCaller<ushort>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskOrCaller<uint>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);


    void bitwiseAndCaller(int rows, int cols, int elem_size1, int cn, const PtrStep src1, 
                          const PtrStep src2, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<BIN_OP_AND>(rows, cols * elem_size1 * cn, src1, src2, dst, stream);
    }


    template <typename T>
    void bitwiseMaskAndCaller(int rows, int cols, int cn, const PtrStep src1, const PtrStep src2, 
                              const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<T, BIN_OP_AND>(rows, cols * cn, cn, src1, src2, mask, dst, stream);
    }

    template void bitwiseMaskAndCaller<uchar>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskAndCaller<ushort>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskAndCaller<uint>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);


    void bitwiseXorCaller(int rows, int cols, int elem_size1, int cn, const PtrStep src1, 
                          const PtrStep src2, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<BIN_OP_XOR>(rows, cols * elem_size1 * cn, src1, src2, dst, stream);
    }


    template <typename T>
    void bitwiseMaskXorCaller(int rows, int cols, int cn, const PtrStep src1, const PtrStep src2, 
                              const PtrStep mask, PtrStep dst, cudaStream_t stream)
    {
        bitwiseBinOp<T, BIN_OP_XOR>(rows, cols * cn, cn, src1, src2, mask, dst, stream);
    }

    template void bitwiseMaskXorCaller<uchar>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskXorCaller<ushort>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);
    template void bitwiseMaskXorCaller<uint>(int, int, int, const PtrStep, const PtrStep, const PtrStep, PtrStep, cudaStream_t);


    //////////////////////////////////////////////////////////////////////////
    // min/max

    struct MinOp
    {        
        template <typename T>
        __device__ __forceinline__ T operator()(T a, T b)
        {
            return min(a, b);
        }
        __device__ __forceinline__ float operator()(float a, float b)
        {
            return fmin(a, b);
        }
        __device__ __forceinline__ double operator()(double a, double b)
        {
            return fmin(a, b);
        }
    };

    struct MaxOp
    {        
        template <typename T>
        __device__ __forceinline__ T operator()(T a, T b)
        {
            return max(a, b);
        }
        __device__ __forceinline__ float operator()(float a, float b)
        {
            return fmax(a, b);
        }
        __device__ __forceinline__ double operator()(double a, double b)
        {
            return fmax(a, b);
        }
    };
    
    template <typename T> struct ScalarMinOp
    {
        T s;

        explicit ScalarMinOp(T s_) : s(s_) {}

        __device__ __forceinline__ T operator()(T a)
        {
            return min(a, s);
        }
    };
    template <> struct ScalarMinOp<float>
    {
        float s;

        explicit ScalarMinOp(float s_) : s(s_) {}

        __device__ __forceinline__ float operator()(float a)
        {
            return fmin(a, s);
        }
    };
    template <> struct ScalarMinOp<double>
    {
        double s;

        explicit ScalarMinOp(double s_) : s(s_) {}

        __device__ __forceinline__ double operator()(double a)
        {
            return fmin(a, s);
        }
    };
    
    template <typename T> struct ScalarMaxOp
    {
        T s;

        explicit ScalarMaxOp(T s_) : s(s_) {}

        __device__ __forceinline__ T operator()(T a)
        {
            return max(a, s);
        }
    };
    template <> struct ScalarMaxOp<float>
    {
        float s;

        explicit ScalarMaxOp(float s_) : s(s_) {}

        __device__ __forceinline__ float operator()(float a)
        {
            return fmax(a, s);
        }
    };
    template <> struct ScalarMaxOp<double>
    {
        double s;

        explicit ScalarMaxOp(double s_) : s(s_) {}

        __device__ __forceinline__ double operator()(double a)
        {
            return fmax(a, s);
        }
    };
    
    template <typename T>
    void min_gpu(const DevMem2D_<T>& src1, const DevMem2D_<T>& src2, const DevMem2D_<T>& dst, cudaStream_t stream)
    {
        MinOp op;
        transform(src1, src2, dst, op, stream);    
    }

    template void min_gpu<uchar >(const DevMem2D& src1, const DevMem2D& src2, const DevMem2D& dst, cudaStream_t stream);
    template void min_gpu<schar >(const DevMem2D_<schar>& src1, const DevMem2D_<schar>& src2, const DevMem2D_<schar>& dst, cudaStream_t stream);
    template void min_gpu<ushort>(const DevMem2D_<ushort>& src1, const DevMem2D_<ushort>& src2, const DevMem2D_<ushort>& dst, cudaStream_t stream);
    template void min_gpu<short >(const DevMem2D_<short>& src1, const DevMem2D_<short>& src2, const DevMem2D_<short>& dst, cudaStream_t stream);
    template void min_gpu<int   >(const DevMem2D_<int>& src1, const DevMem2D_<int>& src2, const DevMem2D_<int>& dst, cudaStream_t stream);
    template void min_gpu<float >(const DevMem2D_<float>& src1, const DevMem2D_<float>& src2, const DevMem2D_<float>& dst, cudaStream_t stream);
    template void min_gpu<double>(const DevMem2D_<double>& src1, const DevMem2D_<double>& src2, const DevMem2D_<double>& dst, cudaStream_t stream);

    template <typename T>
    void max_gpu(const DevMem2D_<T>& src1, const DevMem2D_<T>& src2, const DevMem2D_<T>& dst, cudaStream_t stream)
    {
        MaxOp op;
        transform(src1, src2, dst, op, stream);    
    }
    
    template void max_gpu<uchar >(const DevMem2D& src1, const DevMem2D& src2, const DevMem2D& dst, cudaStream_t stream);
    template void max_gpu<schar >(const DevMem2D_<schar>& src1, const DevMem2D_<schar>& src2, const DevMem2D_<schar>& dst, cudaStream_t stream);
    template void max_gpu<ushort>(const DevMem2D_<ushort>& src1, const DevMem2D_<ushort>& src2, const DevMem2D_<ushort>& dst, cudaStream_t stream);
    template void max_gpu<short >(const DevMem2D_<short>& src1, const DevMem2D_<short>& src2, const DevMem2D_<short>& dst, cudaStream_t stream);
    template void max_gpu<int   >(const DevMem2D_<int>& src1, const DevMem2D_<int>& src2, const DevMem2D_<int>& dst, cudaStream_t stream);
    template void max_gpu<float >(const DevMem2D_<float>& src1, const DevMem2D_<float>& src2, const DevMem2D_<float>& dst, cudaStream_t stream);
    template void max_gpu<double>(const DevMem2D_<double>& src1, const DevMem2D_<double>& src2, const DevMem2D_<double>& dst, cudaStream_t stream);

    template <typename T>
    void min_gpu(const DevMem2D_<T>& src1, T src2, const DevMem2D_<T>& dst, cudaStream_t stream)
    {
        ScalarMinOp<T> op(src2);
        transform(src1, dst, op, stream);    
    }

    template void min_gpu<uchar >(const DevMem2D& src1, uchar src2, const DevMem2D& dst, cudaStream_t stream);
    template void min_gpu<schar >(const DevMem2D_<schar>& src1, schar src2, const DevMem2D_<schar>& dst, cudaStream_t stream);
    template void min_gpu<ushort>(const DevMem2D_<ushort>& src1, ushort src2, const DevMem2D_<ushort>& dst, cudaStream_t stream);
    template void min_gpu<short >(const DevMem2D_<short>& src1, short src2, const DevMem2D_<short>& dst, cudaStream_t stream);
    template void min_gpu<int   >(const DevMem2D_<int>& src1, int src2, const DevMem2D_<int>& dst, cudaStream_t stream);
    template void min_gpu<float >(const DevMem2D_<float>& src1, float src2, const DevMem2D_<float>& dst, cudaStream_t stream);
    template void min_gpu<double>(const DevMem2D_<double>& src1, double src2, const DevMem2D_<double>& dst, cudaStream_t stream);
    
    template <typename T>
    void max_gpu(const DevMem2D_<T>& src1, T src2, const DevMem2D_<T>& dst, cudaStream_t stream)
    {
        ScalarMaxOp<T> op(src2);
        transform(src1, dst, op, stream);    
    }

    template void max_gpu<uchar >(const DevMem2D& src1, uchar src2, const DevMem2D& dst, cudaStream_t stream);
    template void max_gpu<schar >(const DevMem2D_<schar>& src1, schar src2, const DevMem2D_<schar>& dst, cudaStream_t stream);
    template void max_gpu<ushort>(const DevMem2D_<ushort>& src1, ushort src2, const DevMem2D_<ushort>& dst, cudaStream_t stream);
    template void max_gpu<short >(const DevMem2D_<short>& src1, short src2, const DevMem2D_<short>& dst, cudaStream_t stream);
    template void max_gpu<int   >(const DevMem2D_<int>& src1, int src2, const DevMem2D_<int>& dst, cudaStream_t stream);
    template void max_gpu<float >(const DevMem2D_<float>& src1, float src2, const DevMem2D_<float>& dst, cudaStream_t stream);
    template void max_gpu<double>(const DevMem2D_<double>& src1, double src2, const DevMem2D_<double>& dst, cudaStream_t stream);

    
    //////////////////////////////////////////////////////////////////////////
    // threshold

    template <typename T> struct ThreshBinary
    {
        ThreshBinary(T thresh_, T maxVal_) : thresh(thresh_), maxVal(maxVal_) {}

        __device__ __forceinline__ T operator()(const T& src) const
        {
            return src > thresh ? maxVal : 0;
        }

    private:
        T thresh;
        T maxVal;
    };

    template <typename T> struct ThreshBinaryInv
    {
        ThreshBinaryInv(T thresh_, T maxVal_) : thresh(thresh_), maxVal(maxVal_) {}

        __device__ __forceinline__ T operator()(const T& src) const
        {
            return src > thresh ? 0 : maxVal;
        }

    private:
        T thresh;
        T maxVal;
    };

    template <typename T> struct ThreshTrunc
    {
        ThreshTrunc(T thresh_, T) : thresh(thresh_) {}

        __device__ __forceinline__ T operator()(const T& src) const
        {
            return min(src, thresh);
        }

    private:
        T thresh;
    };
    template <> struct  ThreshTrunc<float>
    {
        ThreshTrunc(float thresh_, float) : thresh(thresh_) {}

        __device__ __forceinline__ float operator()(const float& src) const
        {
            return fmin(src, thresh);
        }

    private:
        float thresh;
    };
    template <> struct  ThreshTrunc<double>
    {
        ThreshTrunc(double thresh_, double) : thresh(thresh_) {}

        __device__ __forceinline__ double operator()(const double& src) const
        {
            return fmin(src, thresh);
        }

    private:
        double thresh;
    };

    template <typename T> struct ThreshToZero
    {
    public:
        ThreshToZero(T thresh_, T) : thresh(thresh_) {}

        __device__ __forceinline__ T operator()(const T& src) const
        {
            return src > thresh ? src : 0;
        }

    private:
        T thresh;
    };

    template <typename T> struct ThreshToZeroInv
    {
    public:
        ThreshToZeroInv(T thresh_, T) : thresh(thresh_) {}

        __device__ __forceinline__ T operator()(const T& src) const
        {
            return src > thresh ? 0 : src;
        }

    private:
        T thresh;
    };

    template <template <typename> class Op, typename T>
    void threshold_caller(const DevMem2D_<T>& src, const DevMem2D_<T>& dst, T thresh, T maxVal, 
        cudaStream_t stream)
    {
        Op<T> op(thresh, maxVal);
        transform(src, dst, op, stream);
    }

    template <typename T>
    void threshold_gpu(const DevMem2D& src, const DevMem2D& dst, T thresh, T maxVal, int type,
        cudaStream_t stream)
    {
        typedef void (*caller_t)(const DevMem2D_<T>& src, const DevMem2D_<T>& dst, T thresh, T maxVal, 
            cudaStream_t stream);

        static const caller_t callers[] = 
        {
            threshold_caller<ThreshBinary, T>, 
            threshold_caller<ThreshBinaryInv, T>, 
            threshold_caller<ThreshTrunc, T>, 
            threshold_caller<ThreshToZero, T>, 
            threshold_caller<ThreshToZeroInv, T>
        };

        callers[type]((DevMem2D_<T>)src, (DevMem2D_<T>)dst, thresh, maxVal, stream);
    }

    template void threshold_gpu<uchar>(const DevMem2D& src, const DevMem2D& dst, uchar thresh, uchar maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<schar>(const DevMem2D& src, const DevMem2D& dst, schar thresh, schar maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<ushort>(const DevMem2D& src, const DevMem2D& dst, ushort thresh, ushort maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<short>(const DevMem2D& src, const DevMem2D& dst, short thresh, short maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<int>(const DevMem2D& src, const DevMem2D& dst, int thresh, int maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<float>(const DevMem2D& src, const DevMem2D& dst, float thresh, float maxVal, int type, cudaStream_t stream);
    template void threshold_gpu<double>(const DevMem2D& src, const DevMem2D& dst, double thresh, double maxVal, int type, cudaStream_t stream);


    //////////////////////////////////////////////////////////////////////////
    // subtract

    template <typename T>
    class SubtractOp
    {
    public:
        __device__ __forceinline__ T operator()(const T& l, const T& r) const
        {
            return l - r;
        }
    };

    template <typename T>
    void subtractCaller(const DevMem2D src1, const DevMem2D src2, DevMem2D dst, cudaStream_t stream)
    {
        transform((DevMem2D_<T>)src1, (DevMem2D_<T>)src2, (DevMem2D_<T>)dst, SubtractOp<T>(), stream);
    }

    template void subtractCaller<short>(const DevMem2D src1, const DevMem2D src2, DevMem2D dst, cudaStream_t stream);


    //////////////////////////////////////////////////////////////////////////
    // pow
    
    template<typename T, bool Signed = device::numeric_limits_gpu<T>::is_signed>
    struct PowOp
    {    
        float power;
        PowOp(float power_) : power(power_) {}
            
        __device__ __forceinline__ T operator()(const T& e) const
        {      
            return saturate_cast<U>(__powf((float)e, power));
        }      
    };

    template<typename T>
    struct PowOp<T, true>
    {
        float power;
        PowOp(float power_) : power(power_) {}

        __device__ __forceinline__ float operator()(const T& e)
        {
              T res = saturate_cast<T>(__powf((float)e, power));            
            
            if ( (e < 0) && (1 & (int)power) )
                    res *= -1;            
            return res;         
        }
    };

    template<>
    struct PowOp<float>
    {
        float power;
        PowOp(float power_) : power(power_) {}

        __device__ __forceinline__ float operator()(const float& e)
        {
            return __powf(fabs(e), power);
        }
    };

    template<typename T>
    void pow_caller(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream)
    {
        transform((DevMem2D_<T>)src, (DevMem2D_<T>)dst, PowOp<T>(power), stream);
    }   

    template void pow_caller<uchar>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<schar>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<short>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<ushort>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<int>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<uint>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
    template void pow_caller<float>(const DevMem2D& src, float power, DevMem2D dst, cudaStream_t stream);
}}}