#ifndef THC_NUMERICS_INC
#define THC_NUMERICS_INC

#include <cuda.h>
#include <limits.h>
#include <assert.h>
#include "THCHalf.h"
#include "ATen/ATen.h"
#include "ATen/cuda/NumericLimits.cuh"

// WARNING: THCNumerics is being deprecated. Please follow the comments
// in this file to learn about new usages.
// Comments on usage:
//      - lt,le,gt,ge,eq,neg,add,mul,sub,div and other binary ops can
//        be implemented using CUDA_apply_utils or binary cuda kernel
//      - Check NumericLimits.cuh for specialized math functions.
//      - Note how __half and at::Half can be casted. for instance:
//        static_cast<at::Half>(std::sin(static_cast<at::Half>(a)));

template <typename T>
struct THCNumerics {
};

template <typename scalar_t>
static inline __host__ __device__ scalar_t powi(scalar_t a, scalar_t b) {
  assert(THCNumerics<scalar_t>::ge(b, 0));
  scalar_t result = 1;
  while (b) {
    if (b & 1) {
       result *= a;
    }
    b /= 2;
    a *= a;
  }
  return result;
}

// DEPRECATED: For integral types, use math functions from std and NumericLimits.cuh. 
//             Use binary_kernel or CUDA_apply_utils for arithmetic
template <>
struct THCNumerics<uint8_t> {
  static inline __host__ __device__ uint8_t min() { return at::numeric_limits<uint8_t>::lowest(); }
  static inline __host__ __device__ uint8_t max() { return at::numeric_limits<uint8_t>::max(); }

  static inline __host__ __device__ bool lt(uint8_t a, uint8_t b) { return a < b; }
  static inline __host__ __device__ bool le(uint8_t a, uint8_t b) { return a <= b; }
  static inline __host__ __device__ bool gt(uint8_t a, uint8_t b) { return a > b; }
  static inline __host__ __device__ bool ge(uint8_t a, uint8_t b) { return a >= b; }
  static inline __host__ __device__ bool eq(uint8_t a, uint8_t b) { return a == b; }
  static inline __host__ __device__ bool ne(uint8_t a, uint8_t b) { return a != b; }

  static inline __host__ __device__  uint8_t neg(int8_t a) { return -a; }
  static inline __host__ __device__  uint8_t add(uint8_t a, uint8_t b) { return a + b; }
  static inline __host__ __device__  uint8_t mul(uint8_t a, uint8_t b) { return a * b; }
  static inline __host__ __device__  uint8_t sub(uint8_t a, uint8_t b) { return a - b; }
  static inline __host__ __device__  uint8_t div(uint8_t a, uint8_t b) { return a / b; }
  static inline __host__ __device__  uint8_t abs(uint8_t a) { return a; }
  static inline __host__ __device__  uint8_t pow(uint8_t a, uint8_t b) { return powi<uint8_t>(a, b); }
  static inline __host__ __device__  bool isnan(uint8_t a) { return false; }
  static inline __host__ __device__  bool isinf(uint8_t a) { return false; }
};

template <>
struct THCNumerics<int8_t> {
  static inline __host__ __device__ int8_t min() { return at::numeric_limits<int8_t>::lowest(); }
  static inline __host__ __device__ int8_t max() { return at::numeric_limits<int8_t>::max(); }

  static inline __host__ __device__ bool lt(int8_t a, int8_t b) { return a < b; }
  static inline __host__ __device__ bool le(int8_t a, int8_t b) { return a <= b; }
  static inline __host__ __device__ bool gt(int8_t a, int8_t b) { return a > b; }
  static inline __host__ __device__ bool ge(int8_t a, int8_t b) { return a >= b; }
  static inline __host__ __device__ bool eq(int8_t a, int8_t b) { return a == b; }
  static inline __host__ __device__ bool ne(int8_t a, int8_t b) { return a != b; }

  static inline __host__ __device__  int8_t neg(int8_t a) { return -a; }
  static inline __host__ __device__  int8_t add(int8_t a, int8_t b) { return a + b; }
  static inline __host__ __device__  int8_t mul(int8_t a, int8_t b) { return a * b; }
  static inline __host__ __device__  int8_t sub(int8_t a, int8_t b) { return a - b; }
  static inline __host__ __device__  int8_t div(int8_t a, int8_t b) { return a / b; }
  static inline __host__ __device__  int8_t abs(int8_t a) { return ::abs((int)a); }
  static inline __host__ __device__  int8_t pow(int8_t a, int8_t b) { return powi<int8_t>(a, b); }
  static inline __host__ __device__  bool isnan(int8_t a) { return false; }
  static inline __host__ __device__  bool isinf(int8_t a) { return false; }
};

template <>
struct THCNumerics<int16_t> {
  static inline __host__ __device__ int16_t min() { return at::numeric_limits<int16_t>::lowest(); }
  static inline __host__ __device__ int16_t max() { return at::numeric_limits<int16_t>::max(); }

  static inline __host__ __device__ bool lt(int16_t a, int16_t b) { return a < b; }
  static inline __host__ __device__ bool le(int16_t a, int16_t b) { return a <= b; }
  static inline __host__ __device__ bool gt(int16_t a, int16_t b) { return a > b; }
  static inline __host__ __device__ bool ge(int16_t a, int16_t b) { return a >= b; }
  static inline __host__ __device__ bool eq(int16_t a, int16_t b) { return a == b; }
  static inline __host__ __device__ bool ne(int16_t a, int16_t b) { return a != b; }

  static inline __host__ __device__  int16_t neg(int16_t a) { return -a; }
  static inline __host__ __device__  int16_t add(int16_t a, int16_t b) { return a + b; }
  static inline __host__ __device__  int16_t mul(int16_t a, int16_t b) { return a * b; }
  static inline __host__ __device__  int16_t sub(int16_t a, int16_t b) { return a - b; }
  static inline __host__ __device__  int16_t div(int16_t a, int16_t b) { return a / b; }
  static inline __host__ __device__  int16_t abs(int16_t a) { return ::abs((int)a); }
  static inline __host__ __device__  int16_t pow(int16_t a, int16_t b) { return powi<int16_t>(a, b); }
  static inline __host__ __device__  bool isnan(int16_t a) { return false; }
  static inline __host__ __device__  bool isinf(int16_t a) { return false; }
};

template <>
struct THCNumerics<int32_t> {
  static inline __host__ __device__ int32_t min() { return at::numeric_limits<int32_t>::lowest(); }
  static inline __host__ __device__ int32_t max() { return at::numeric_limits<int32_t>::max(); }

  static inline __host__ __device__ bool lt(int32_t a, int32_t b) { return a < b; }
  static inline __host__ __device__ bool le(int32_t a, int32_t b) { return a <= b; }
  static inline __host__ __device__ bool gt(int32_t a, int32_t b) { return a > b; }
  static inline __host__ __device__ bool ge(int32_t a, int32_t b) { return a >= b; }
  static inline __host__ __device__ bool eq(int32_t a, int32_t b) { return a == b; }
  static inline __host__ __device__ bool ne(int32_t a, int32_t b) { return a != b; }

  static inline __host__ __device__  int32_t neg(int32_t a) { return -a; }
  static inline __host__ __device__  int32_t add(int32_t a, int32_t b) { return a + b; }
  static inline __host__ __device__  int32_t mul(int32_t a, int32_t b) { return a * b; }
  static inline __host__ __device__  int32_t sub(int32_t a, int32_t b) { return a - b; }
  static inline __host__ __device__  int32_t div(int32_t a, int32_t b) { return a / b; }
  static inline __host__ __device__  int32_t abs(int32_t a) { return ::abs(a); }
  static inline __host__ __device__  int32_t pow(int32_t a, int32_t b) { return powi<int32_t>(a, b); }
  static inline __host__ __device__  bool isnan(int32_t a) { return false; }
  static inline __host__ __device__  bool isinf(int32_t a) { return false; }
};

template <>
struct THCNumerics<int64_t> {
  static inline __host__ __device__ int64_t min() { return at::numeric_limits<int64_t>::lowest(); }
  static inline __host__ __device__ int64_t max() { return at::numeric_limits<int64_t>::max(); }

  static inline __host__ __device__ bool lt(int64_t a, int64_t b) { return a < b; }
  static inline __host__ __device__ bool le(int64_t a, int64_t b) { return a <= b; }
  static inline __host__ __device__ bool gt(int64_t a, int64_t b) { return a > b; }
  static inline __host__ __device__ bool ge(int64_t a, int64_t b) { return a >= b; }
  static inline __host__ __device__ bool eq(int64_t a, int64_t b) { return a == b; }
  static inline __host__ __device__ bool ne(int64_t a, int64_t b) { return a != b; }


  static inline __host__ __device__  int64_t neg(int64_t a) { return -a; }
  static inline __host__ __device__  int64_t add(int64_t a, int64_t b) { return a + b; }
  static inline __host__ __device__  int64_t mul(int64_t a, int64_t b) { return a * b; }
  static inline __host__ __device__  int64_t sub(int64_t a, int64_t b) { return a - b; }
  static inline __host__ __device__  int64_t div(int64_t a, int64_t b) { return a / b; };
  static inline __host__ __device__  int64_t abs(int64_t a) { return labs(a); }
  static inline __host__ __device__  int64_t pow(int64_t a, int64_t b) { return powi<int64_t>(a, b); }
  static inline __host__ __device__  bool isnan(int64_t a) { return false; }
  static inline __host__ __device__  bool isinf(int64_t a) { return false; }
};

// DEPRECATED: use math functions from std and NumericLimits.cuh
template <>
struct THCNumerics<half> {
  static inline __host__ __device__ half min() { return at::numeric_limits<at::Half>::lowest(); }
  static inline __host__ __device__ half max() { return at::numeric_limits<at::Half>::max(); }

  static inline __host__ __device__ bool lt(half a, half b) {
    return static_cast<at::Half>(a) < static_cast<at::Half>(b);
  }

  static inline __host__ __device__ bool le(half a, half b) {
    return static_cast<at::Half>(a) <= static_cast<at::Half>(b);
  }

  static inline __host__ __device__ bool gt(half a, half b) {
    return static_cast<at::Half>(a) > static_cast<at::Half>(b);
  }

  static inline __host__ __device__ bool ge(half a, half b) {
    return static_cast<at::Half>(a) >= static_cast<at::Half>(b);
  }

  static inline __host__ __device__ bool eq(half a, half b) {
    // has to be explicitly casted to float for now, otherwise get error: more than one operator "==" matches these operands
    // Note: find the overloading for == and != (probably THCTensorTypeUtils.cuh) and resolve
    return static_cast<float>(static_cast<at::Half>(a)) == static_cast<float>(static_cast<at::Half>(b));
  }

  static inline __host__ __device__ bool ne(half a, half b) {
    // has to be explicitly casted to float for now, otherwise get error: more than one operator "==" matches these operands
    // Note: find the overloading for == and != (probably THCTensorTypeUtils.cuh) and resolve
    return static_cast<float>(static_cast<at::Half>(a)) != static_cast<float>(static_cast<at::Half>(b));
  }

  static inline __host__ __device__ half exp(half a) {
    return static_cast<at::Half>(std::exp(static_cast<at::Half>(a)));
  }
  
  // note that exp10 is not in the std namespace. 
  static inline __host__ __device__ half exp10(half a) {
    return static_cast<at::Half>(::exp10(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half log(half a) {
    return static_cast<at::Half>(::log(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half log10(half a) {
    return static_cast<at::Half>(::log10(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half log1p(half a) {
    return static_cast<at::Half>(::log1p(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half log2(half a) {
    return static_cast<at::Half>(::log2(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half lgamma(half a) {
    return static_cast<at::Half>(::lgamma(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half expm1(half a) {
    return static_cast<at::Half>(::expm1(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half cos(half a) {
    return static_cast<at::Half>(::cos(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half sin(half a) {
    return static_cast<at::Half>(::sin(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half sqrt(half a) {
    return static_cast<at::Half>(::sqrt(static_cast<at::Half>(a)));
  }

  // note that rsqrt is not in the std namespace. 
  static inline __host__ __device__ half rsqrt(half a) {
    return static_cast<at::Half>(::rsqrt(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half ceil(half a) {
    return static_cast<at::Half>(::ceil(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half floor(half a) {
    return static_cast<at::Half>(::floor(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half trunc(half a) {
    return static_cast<at::Half>(::trunc(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half neg(half a) {
    return static_cast<at::Half>(-(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half acos(half a) {
    return static_cast<at::Half>(::acos(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half cosh(half a) {
    return static_cast<at::Half>(::cosh(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half asin(half a) {
    return static_cast<at::Half>(::asin(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half sinh(half a) {
    return static_cast<at::Half>(::sinh(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half tan(half a) {
    return static_cast<at::Half>(::tan(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half atan(half a) {
    return static_cast<at::Half>(::atan(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half tanh(half a) {
    return static_cast<at::Half>(::tanh(static_cast<at::Half>(a)));
  }


   static inline __host__ __device__ half erf(half a) {
    return static_cast<at::Half>(::erf(static_cast<at::Half>(a)));
  }


   static inline __host__ __device__ half erfc(half a) {
    return static_cast<at::Half>(::erfc(static_cast<at::Half>(a)));
  }

  // note that erfinv is not in the std namespace.
  static inline __host__ __device__ half erfinv(half a) {
    return static_cast<at::Half>(::erfinv(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half abs(half a) {
    return static_cast<at::Half>(::abs(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half round(half a) {
    return static_cast<at::Half>(::round(static_cast<at::Half>(a)));
  }

  static inline __host__ __device__ half frac(half a) {
    #ifdef __CUDA_ARCH__
        return static_cast<at::Half>(a) - static_cast<at::Half>(::trunc(static_cast<at::Half>(a)));
    #else // __CUDA_ARCH__
        return static_cast<at::Half>(a) - static_cast<at::Half>(::floor(static_cast<at::Half>(a)));
    #endif
  }

  static inline __host__ __device__ half cinv(half a) {
    return static_cast<at::Half>(1.0f / static_cast<at::Half>(a));
  }

  static inline __host__ __device__ half add(half a, half b) {
    return static_cast<at::Half>(a) + static_cast<at::Half>(b);
  }

  static inline __host__ __device__ half div(half a, half b) {
    return static_cast<at::Half>(a) / static_cast<at::Half>(b);
  }

  static inline __host__ __device__ half mul(half a, half b) {
    return static_cast<at::Half>(a) * static_cast<at::Half>(b);
  }

  static inline __host__ __device__ half sub(half a, half b) {
    return static_cast<at::Half>(a) - static_cast<at::Half>(b);
  }

  static inline __host__ __device__ half pow(half a, half b) {
    return static_cast<at::Half>(::pow(static_cast<at::Half>(a), static_cast<at::Half>(b)));
  }

  static inline __host__ __device__ half atan2(half a, half b) {
    return static_cast<at::Half>(::atan2(static_cast<at::Half>(a), static_cast<at::Half>(b)));
  }

  static inline __host__ __device__ bool isnan(half a) {
    #ifdef _MSC_VER
      // Windows requires this explicit conversion. The reason is unclear
      // related issue with clang: https://reviews.llvm.org/D37906
      return ::isnan((float)static_cast<at::Half>(a));
    #else
      return ::isnan(static_cast<at::Half>(a));
    #endif
  }

  static inline __host__ __device__ bool isinf(half a) {
    #ifdef _MSC_VER
      // Windows requires this explicit conversion. The reason is unclear
      // related issue with clang: https://reviews.llvm.org/D37906
      return ::isinf((float)static_cast<at::Half>(a));
    #else
      return ::isinf(static_cast<at::Half>(a));
    #endif
  }

};

// DEPRECATED: use math functions from std and cuda math API (if needed)
//             note that the functions exp10,rsqrt,erfinv,frac and cinv
//             are not in the std namespace
template <>
struct THCNumerics<float> {
  static inline __host__ __device__ float min() { return at::numeric_limits<float>::lowest(); }
  static inline __host__ __device__ float max() { return at::numeric_limits<float>::max(); }

  static inline __host__ __device__ bool lt(float a, float b) { return a < b; }
  static inline __host__ __device__ bool le(float a, float b) { return a <= b; }
  static inline __host__ __device__ bool gt(float a, float b) { return a > b; }
  static inline __host__ __device__ bool ge(float a, float b) { return a >= b; }
  static inline __host__ __device__ bool eq(float a, float b) { return a == b; }
  static inline __host__ __device__ bool ne(float a, float b) { return a != b; }

  static inline __host__ __device__  float lgamma(float a) { return lgammaf(a);}
  static inline __host__ __device__  float erfinv(float a) { return erfinvf(a);}
  static inline __host__ __device__  float exp  (float a) { return   expf(a); }
  static inline __host__ __device__  float exp10(float a) { return exp10f(a); }
  static inline __host__ __device__  float log  (float a) { return   logf(a); }
  static inline __host__ __device__  float log10(float a) { return log10f(a); }
  static inline __host__ __device__  float log1p(float a) { return log1pf(a); }
  static inline __host__ __device__  float log2 (float a) { return  log2f(a); }
  static inline __host__ __device__  float expm1(float a) { return expm1f(a); }
  static inline __host__ __device__  float cos  (float a) { return   cosf(a); }
  static inline __host__ __device__  float sin  (float a) { return   sinf(a); }
  static inline __host__ __device__  float sqrt (float a) { return  sqrtf(a); }
  static inline __host__ __device__  float rsqrt(float a) { return rsqrtf(a); }
  static inline __host__ __device__  float ceil (float a) { return  ceilf(a); }
  static inline __host__ __device__  float floor(float a) { return floorf(a); }
  static inline __host__ __device__  float trunc(float a) { return truncf(a); }
  static inline __host__ __device__  float neg  (float a) { return        -a; }
  static inline __host__ __device__  float acos (float a) { return  acosf(a); }
  static inline __host__ __device__  float cosh (float a) { return  coshf(a); }
  static inline __host__ __device__  float acosh(float a) { return acoshf(a); }
  static inline __host__ __device__  float asin (float a) { return  asinf(a); }
  static inline __host__ __device__  float sinh (float a) { return  sinhf(a); }
  static inline __host__ __device__  float asinh(float a) { return asinhf(a); }
  static inline __host__ __device__  float tan  (float a) { return   tanf(a); }
  static inline __host__ __device__  float atan (float a) { return  atanf(a); }
  static inline __host__ __device__  float tanh (float a) { return  tanhf(a); }
  static inline __host__ __device__  float erf  (float a) { return   erff(a); }
  static inline __host__ __device__  float erfc (float a) { return  erfcf(a); }
  static inline __host__ __device__  float abs  (float a) { return  fabsf(a); }
  static inline __host__ __device__  float round(float a) { return roundf(a); }
  static inline __host__ __device__  float frac (float a) { return a - truncf(a); }
  static inline __host__ __device__  float cinv (float a) { return 1.0f / a; }
  static inline __host__ __device__  float add  (float a, float b) { return a + b; }
  static inline __host__ __device__  float div  (float a, float b) { return a / b; }
  static inline __host__ __device__  float mul  (float a, float b) { return a * b; }
  static inline __host__ __device__  float sub  (float a, float b) { return a - b; }
  static inline __host__ __device__  float pow  (float a, float b) { return powf(a, b); }
  static inline __host__ __device__  float atan2(float a, float b) { return atan2f(a, b); }
  static inline __host__ __device__  bool isnan(float a) { return ::isnan(a); }
  static inline __host__ __device__  bool isinf(float a) { return ::isinf(a); }
};

// DEPRECATED: use math functions from std and cuda math API (if needed)
//             note that the functions exp10,rsqrt,erfinv,frac and cinv
//             are not in the std namespace
template <>
struct THCNumerics<double> {
  static inline __host__ __device__ double min() { return at::numeric_limits<double>::lowest(); }
  static inline __host__ __device__ double max() { return at::numeric_limits<double>::max(); }

  static inline __host__ __device__ bool lt(double a, double b) { return a < b; }
  static inline __host__ __device__ bool le(double a, double b) { return a <= b; }
  static inline __host__ __device__ bool gt(double a, double b) { return a > b; }
  static inline __host__ __device__ bool ge(double a, double b) { return a >= b; }
  static inline __host__ __device__ bool eq(double a, double b) { return a == b; }
  static inline __host__ __device__ bool ne(double a, double b) { return a != b; }

  static inline __host__ __device__  double lgamma(double a) { return ::lgamma(a);}
  static inline __host__ __device__  double erfinv(double a) { return ::erfinv(a);}
  static inline __host__ __device__  double exp  (double a) { return   ::exp(a); }
  static inline __host__ __device__  double exp10(double a) { return ::exp10(a); }
  static inline __host__ __device__  double log  (double a) { return   ::log(a); }
  static inline __host__ __device__  double log10(double a) { return ::log10(a); }
  static inline __host__ __device__  double log1p(double a) { return ::log1p(a); }
  static inline __host__ __device__  double log2 (double a) { return  ::log2(a); }
  static inline __host__ __device__  double expm1(double a) { return ::expm1(a); }
  static inline __host__ __device__  double cos  (double a) { return   ::cos(a); }
  static inline __host__ __device__  double sin  (double a) { return   ::sin(a); }
  static inline __host__ __device__  double sqrt (double a) { return  ::sqrt(a); }
  static inline __host__ __device__  double rsqrt(double a) { return ::rsqrt(a); }
  static inline __host__ __device__  double ceil (double a) { return  ::ceil(a); }
  static inline __host__ __device__  double floor(double a) { return ::floor(a); }
  static inline __host__ __device__  double trunc(double a) { return ::trunc(a); }
  static inline __host__ __device__  double neg  (double a) { return       -a; }
  static inline __host__ __device__  double acos (double a) { return  ::acos(a); }
  static inline __host__ __device__  double cosh (double a) { return  ::cosh(a); }
  static inline __host__ __device__  double acosh(double a) { return ::acosh(a); }
  static inline __host__ __device__  double asin (double a) { return  ::asin(a); }
  static inline __host__ __device__  double sinh (double a) { return  ::sinh(a); }
  static inline __host__ __device__  double asinh(double a) { return ::asinh(a); }
  static inline __host__ __device__  double tan  (double a) { return   ::tan(a); }
  static inline __host__ __device__  double atan (double a) { return  ::atan(a); }
  static inline __host__ __device__  double tanh (double a) { return  ::tanh(a); }
  static inline __host__ __device__  double erf  (double a) { return   ::erf(a); }
  static inline __host__ __device__  double erfc (double a) { return  ::erfc(a); }
  static inline __host__ __device__  double abs  (double a) { return   fabs(a); }
  static inline __host__ __device__  double round(double a) { return ::round(a); }
  static inline __host__ __device__  double frac (double a) { return a - ::trunc(a); }
  static inline __host__ __device__  double cinv (double a) { return 1.0 / a; }
  static inline __host__ __device__  double add  (double a, double b) { return a + b; }
  static inline __host__ __device__  double div  (double a, double b) { return a / b; }
  static inline __host__ __device__  double mul  (double a, double b) { return a * b; }
  static inline __host__ __device__  double sub  (double a, double b) { return a - b; }
  static inline __host__ __device__  double pow  (double a, double b) { return ::pow(a, b); }
  static inline __host__ __device__  double atan2(double a, double b) { return ::atan2(a, b); }
  static inline __host__ __device__  bool isnan(double a) { return ::isnan(a); }
  static inline __host__ __device__  bool isinf(double a) { return ::isinf(a); }
};

// WARNING: The following note is deprecated
///       `half` has some type conversion issues associated with it, since it
///        is a struct without a constructor/implicit conversion constructor.
///        We use this to convert scalar values to the given type that the
///        tensor expects.
///
/// at::Half has implicit conversions for float and __half types. Moreover
/// it has constructors for __half and float types.

template <typename In, typename Out>
struct ScalarConvert {
  static __host__ __device__ Out to(const In v) { return (Out) v; }
};

template <typename Out>
struct ScalarConvert<half, Out> {
  static __host__ __device__ Out to(const half v) {
#ifdef __CUDA_ARCH__
    return (Out) __half2float(v);
#else
    return (Out) THC_half2float(v);
#endif
  }
};

template <typename In>
struct ScalarConvert<In, half> {
  static __host__ __device__ half to(const In v) {
#ifdef __CUDA_ARCH__
    return __float2half((float) v);
#else
    return THC_float2half((float) v);
#endif
  }
};

template <>
struct ScalarConvert<half, half> {
  static __host__ __device__ half to(const half v) {
    return v;
  }
};

// DEPRECATED: use static_cast in kernels instead of scalar_cast
template <typename T, typename U>
__host__ __device__ T scalar_cast(U u) {
  return ScalarConvert<U, T>::to(u);
}

#endif // THC_NUMERICS_INC
