\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}\begin{array}{l}
\mathbf{if}\;\alpha \le 6566215071237633024:\\
\;\;\;\;\frac{\log \left(e^{\frac{\beta}{\left(\alpha + \beta\right) + 2}}\right) - \log \left(e^{\frac{\alpha}{\left(\alpha + \beta\right) + 2} - 1}\right)}{2}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{\beta}{\left(\alpha + \beta\right) + 2} - \left(\left(\frac{\frac{4}{\alpha}}{\alpha} + \frac{-8}{{\alpha}^{3}}\right) + \frac{-2}{\alpha}\right)}{2}\\
\end{array}double f(double alpha, double beta) {
double r159536 = beta;
double r159537 = alpha;
double r159538 = r159536 - r159537;
double r159539 = r159537 + r159536;
double r159540 = 2.0;
double r159541 = r159539 + r159540;
double r159542 = r159538 / r159541;
double r159543 = 1.0;
double r159544 = r159542 + r159543;
double r159545 = r159544 / r159540;
return r159545;
}
double f(double alpha, double beta) {
double r159546 = alpha;
double r159547 = 6.566215071237633e+18;
bool r159548 = r159546 <= r159547;
double r159549 = beta;
double r159550 = r159546 + r159549;
double r159551 = 2.0;
double r159552 = r159550 + r159551;
double r159553 = r159549 / r159552;
double r159554 = exp(r159553);
double r159555 = log(r159554);
double r159556 = r159546 / r159552;
double r159557 = 1.0;
double r159558 = r159556 - r159557;
double r159559 = exp(r159558);
double r159560 = log(r159559);
double r159561 = r159555 - r159560;
double r159562 = r159561 / r159551;
double r159563 = 4.0;
double r159564 = r159563 / r159546;
double r159565 = r159564 / r159546;
double r159566 = 8.0;
double r159567 = -r159566;
double r159568 = 3.0;
double r159569 = pow(r159546, r159568);
double r159570 = r159567 / r159569;
double r159571 = r159565 + r159570;
double r159572 = -r159551;
double r159573 = r159572 / r159546;
double r159574 = r159571 + r159573;
double r159575 = r159553 - r159574;
double r159576 = r159575 / r159551;
double r159577 = r159548 ? r159562 : r159576;
return r159577;
}



Bits error versus alpha



Bits error versus beta
Results
if alpha < 6.566215071237633e+18Initial program 0.5
rmApplied div-sub0.5
Applied associate-+l-0.5
rmApplied add-log-exp0.5
Applied add-log-exp0.6
Applied diff-log0.6
Simplified0.5
rmApplied add-log-exp0.5
if 6.566215071237633e+18 < alpha Initial program 50.6
rmApplied div-sub50.6
Applied associate-+l-49.1
Taylor expanded around inf 17.9
Simplified17.9
Final simplification6.1
herbie shell --seed 2019346
(FPCore (alpha beta)
:name "Octave 3.8, jcobi/1"
:precision binary64
:pre (and (> alpha -1) (> beta -1))
(/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2)) 1) 2))