csqrt.hpp

#ifndef CONSTMATH_CSQRT_HPP
#define CONSTMATH_CSQRT_HPP
 
#include "../complex.hpp"
#include "../math_backend.hpp"
 
namespace consteig
{
 
 
template <typename T> constexpr Complex<T> csqrt(const T x)
{
    if (x < static_cast<T>(0))
    {
        if constexpr (is_float<T>())
        {
            return {static_cast<T>(0), sqrt(abs(x))};
        }
        else
        {
            // Cast to unsigned long long and negate to safely calculate the
            // absolute value of x, even if x is INT_MIN or INT64_MIN, avoiding
            // overflow.
            return {static_cast<T>(0),
                    static_cast<T>(sqrt(-static_cast<unsigned long long>(x)))};
        }
    }
    else
    {
        if constexpr (is_float<T>())
        {
            return {sqrt(x), static_cast<T>(0)};
        }
        else
        {
            return {static_cast<T>(sqrt(static_cast<unsigned long long>(x))),
                    static_cast<T>(0)};
        }
    }
}
 
 
} // namespace consteig
 
#endif