Function log1p

numexpr3/missing_posix_functions.hpp:19–27

// Double precision versions

inline double log1p(double x)
{
    double u = 1.0 + x;
    if (u == 1.0) {
        return x;
    } else {
        return log(u) * x / (u-1.0);
    }
}

inline double expm1(double x)
{