\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}\begin{array}{l}
\mathbf{if}\;\alpha \le 5062494549189153:\\
\;\;\;\;e^{\left(\sqrt[3]{\log \left(\frac{\frac{\beta}{\left(\alpha + \beta\right) + 2} - \left(\frac{\alpha}{\left(\alpha + \beta\right) + 2} - 1\right)}{2}\right)} \cdot \sqrt[3]{\log \left(\frac{\frac{\beta}{\left(\alpha + \beta\right) + 2} - \left(\frac{\alpha}{\left(\alpha + \beta\right) + 2} - 1\right)}{2}\right)}\right) \cdot \sqrt[3]{\log \left(\frac{\frac{\beta}{\left(\alpha + \beta\right) + 2} - \left(\frac{\alpha}{\left(\alpha + \beta\right) + 2} - 1\right)}{2}\right)}}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{\sqrt[3]{\beta} \cdot \sqrt[3]{\beta}}{\sqrt[3]{\left(\alpha + \beta\right) + 2} \cdot \sqrt[3]{\left(\alpha + \beta\right) + 2}} \cdot \frac{\sqrt[3]{\beta}}{\sqrt[3]{\left(\alpha + \beta\right) + 2}} - \left(\frac{\frac{4}{\alpha}}{\alpha} - \left(\frac{2}{\alpha} - \frac{-8}{{\alpha}^{3}}\right)\right)}{2}\\
\end{array}double f(double alpha, double beta) {
double r54871 = beta;
double r54872 = alpha;
double r54873 = r54871 - r54872;
double r54874 = r54872 + r54871;
double r54875 = 2.0;
double r54876 = r54874 + r54875;
double r54877 = r54873 / r54876;
double r54878 = 1.0;
double r54879 = r54877 + r54878;
double r54880 = r54879 / r54875;
return r54880;
}
double f(double alpha, double beta) {
double r54881 = alpha;
double r54882 = 5062494549189153.0;
bool r54883 = r54881 <= r54882;
double r54884 = beta;
double r54885 = r54881 + r54884;
double r54886 = 2.0;
double r54887 = r54885 + r54886;
double r54888 = r54884 / r54887;
double r54889 = r54881 / r54887;
double r54890 = 1.0;
double r54891 = r54889 - r54890;
double r54892 = r54888 - r54891;
double r54893 = r54892 / r54886;
double r54894 = log(r54893);
double r54895 = cbrt(r54894);
double r54896 = r54895 * r54895;
double r54897 = r54896 * r54895;
double r54898 = exp(r54897);
double r54899 = cbrt(r54884);
double r54900 = r54899 * r54899;
double r54901 = cbrt(r54887);
double r54902 = r54901 * r54901;
double r54903 = r54900 / r54902;
double r54904 = r54899 / r54901;
double r54905 = r54903 * r54904;
double r54906 = 4.0;
double r54907 = r54906 / r54881;
double r54908 = r54907 / r54881;
double r54909 = r54886 / r54881;
double r54910 = 8.0;
double r54911 = -r54910;
double r54912 = 3.0;
double r54913 = pow(r54881, r54912);
double r54914 = r54911 / r54913;
double r54915 = r54909 - r54914;
double r54916 = r54908 - r54915;
double r54917 = r54905 - r54916;
double r54918 = r54917 / r54886;
double r54919 = r54883 ? r54898 : r54918;
return r54919;
}



Bits error versus alpha



Bits error versus beta
Results
if alpha < 5062494549189153.0Initial program 0.4
rmApplied div-sub0.4
Applied associate-+l-0.4
rmApplied add-exp-log0.4
Applied add-exp-log0.4
Applied div-exp0.4
Simplified0.4
rmApplied add-cube-cbrt1.4
if 5062494549189153.0 < alpha Initial program 50.4
rmApplied div-sub50.4
Applied associate-+l-48.7
rmApplied add-cube-cbrt48.9
Applied add-cube-cbrt48.8
Applied times-frac48.8
Taylor expanded around inf 18.4
Simplified18.4
Final simplification6.9
herbie shell --seed 2019303
(FPCore (alpha beta)
:name "Octave 3.8, jcobi/1"
:precision binary64
:pre (and (> alpha -1) (> beta -1))
(/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2)) 1) 2))