Sacado_cmath.hpp

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//                           Sacado Package
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#ifndef SACADO_CMATH_HPP
#define SACADO_CMATH_HPP

#include <cmath>        // for most math functions
#include "Sacado_ConfigDefs.h"

// Define some math functions that aren't usually in cmath
#if !( (defined(_GLIBCXX_USE_C99_MATH_TR1) && defined(__GXX_EXPERIMENTAL_CXX0X__)) || defined(HAVE_SACADO_CXX11) || defined(HAS_C99_TR1_CMATH) || defined(USER_DISABLE_SACADO_TR1_CMATH) )
namespace std {
  inline float acosh(float x) {
    return std::log(x + std::sqrt(x*x - float(1.0))); }
  inline float asinh(float x) {
    return std::log(x + std::sqrt(x*x + float(1.0))); }
  inline float atanh(float x) {
    return float(0.5)*std::log((float(1.0)+x)/(float(1.0)-x)); }

  inline double acosh(double x) {
    return std::log(x + std::sqrt(x*x - double(1.0))); }
  inline double asinh(double x) {
    return std::log(x + std::sqrt(x*x + double(1.0))); }
  inline double atanh(double x) {
    return double(0.5)*std::log((double(1.0)+x)/(double(1.0)-x)); }
}
#endif // HAS_C99_TR1_CMATH

namespace Sacado {

  // Replacement for ternary operator, for scalar types that don't implement
  // logical operations that return bool, e.g., a simd scalar type that returns
  // a simd bool.  Sacado overloaded operators use this internally when ever
  // the ternary operator would be used.  It can also be used by client code.
  template <typename Cond, typename T>
  KOKKOS_INLINE_FUNCTION
  T if_then_else(const Cond cond, const T& a, const T& b) {
    return cond ? a : b;
  }

  // Special version of sqrt(x) that avoids the NaN if x==0 in the derivative.
  // The default implementation just calls the standard sqrt(x).
  template <typename T>
  KOKKOS_INLINE_FUNCTION
  T safe_sqrt(const T& x) {
    using std::sqrt;
    return sqrt(x);
  }

}

#endif // SACADO_CMATH_HPP