\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -5.3888208797845926 \cdot 10^{-12}:\\
\;\;\;\;\sqrt{\frac{\mathsf{expm1}\left(\mathsf{log1p}\left(e^{2 \cdot x} - 1\right)\right)}{\mathsf{fma}\left(-1, 1, e^{x + x}\right)} \cdot \left(e^{x} + 1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(0.5, {x}^{2}, \mathsf{fma}\left(1, x, 2\right)\right)}\\
\end{array}double f(double x) {
double r14776 = 2.0;
double r14777 = x;
double r14778 = r14776 * r14777;
double r14779 = exp(r14778);
double r14780 = 1.0;
double r14781 = r14779 - r14780;
double r14782 = exp(r14777);
double r14783 = r14782 - r14780;
double r14784 = r14781 / r14783;
double r14785 = sqrt(r14784);
return r14785;
}
double f(double x) {
double r14786 = x;
double r14787 = -5.3888208797845926e-12;
bool r14788 = r14786 <= r14787;
double r14789 = 2.0;
double r14790 = r14789 * r14786;
double r14791 = exp(r14790);
double r14792 = 1.0;
double r14793 = r14791 - r14792;
double r14794 = log1p(r14793);
double r14795 = expm1(r14794);
double r14796 = -r14792;
double r14797 = r14786 + r14786;
double r14798 = exp(r14797);
double r14799 = fma(r14796, r14792, r14798);
double r14800 = r14795 / r14799;
double r14801 = exp(r14786);
double r14802 = r14801 + r14792;
double r14803 = r14800 * r14802;
double r14804 = sqrt(r14803);
double r14805 = 0.5;
double r14806 = 2.0;
double r14807 = pow(r14786, r14806);
double r14808 = fma(r14792, r14786, r14789);
double r14809 = fma(r14805, r14807, r14808);
double r14810 = sqrt(r14809);
double r14811 = r14788 ? r14804 : r14810;
return r14811;
}



Bits error versus x
if x < -5.3888208797845926e-12Initial program 0.5
rmApplied flip--0.3
Applied associate-/r/0.3
Simplified0.0
rmApplied expm1-log1p-u0.0
if -5.3888208797845926e-12 < x Initial program 35.8
Taylor expanded around 0 7.9
Simplified7.9
Final simplification0.9
herbie shell --seed 2020065 +o rules:numerics
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))