math.hpp

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#pragma once
 
#include "math/constants.hpp"
#include "math/differences.hpp"
#include "math/la.hpp"
 
namespace precice::math {

inline int sign(double number)
{
  if (greater(number, 0.0)) {
    return 1;
  } else if (greater(0.0, number)) {
    return -1;
  }
  return 0;
}

template <int iexp, typename T>
inline constexpr T pow_int(const T base)
{
  static_assert(iexp >= 0, "Exponent must be an integer greater or equal to zero.");
 
  if (iexp == 0)
    return static_cast<T>(1.);
 
  int exp = iexp;
  T   x   = base;
  T   y   = 1;
  // exponentiation by squaring
  while (exp > 1) {
    if (exp % 2 == 1)
      y *= x;
    x *= x;
    exp /= 2;
  }
  return x * y;
}
 
} // namespace precice::math