\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)\frac{\cos th}{\sqrt{\sqrt[3]{\sqrt{2}} \cdot \sqrt[3]{\sqrt{2}}}} \cdot \left(\frac{\frac{1}{\sqrt{\sqrt{2}}}}{\sqrt{\sqrt[3]{\sqrt{2}}}} \cdot \left(a1 \cdot a1\right)\right) + \cos th \cdot \frac{{a2}^{2}}{\sqrt{2}}double f(double a1, double a2, double th) {
double r114740 = th;
double r114741 = cos(r114740);
double r114742 = 2.0;
double r114743 = sqrt(r114742);
double r114744 = r114741 / r114743;
double r114745 = a1;
double r114746 = r114745 * r114745;
double r114747 = r114744 * r114746;
double r114748 = a2;
double r114749 = r114748 * r114748;
double r114750 = r114744 * r114749;
double r114751 = r114747 + r114750;
return r114751;
}
double f(double a1, double a2, double th) {
double r114752 = th;
double r114753 = cos(r114752);
double r114754 = 2.0;
double r114755 = sqrt(r114754);
double r114756 = cbrt(r114755);
double r114757 = r114756 * r114756;
double r114758 = sqrt(r114757);
double r114759 = r114753 / r114758;
double r114760 = 1.0;
double r114761 = sqrt(r114755);
double r114762 = r114760 / r114761;
double r114763 = sqrt(r114756);
double r114764 = r114762 / r114763;
double r114765 = a1;
double r114766 = r114765 * r114765;
double r114767 = r114764 * r114766;
double r114768 = r114759 * r114767;
double r114769 = a2;
double r114770 = 2.0;
double r114771 = pow(r114769, r114770);
double r114772 = r114771 / r114755;
double r114773 = r114753 * r114772;
double r114774 = r114768 + r114773;
return r114774;
}



Bits error versus a1



Bits error versus a2



Bits error versus th
Results
Initial program 0.5
rmApplied div-inv0.5
Applied associate-*l*0.5
Simplified0.5
rmApplied add-sqr-sqrt0.5
Applied sqrt-prod0.5
Applied associate-/r*0.5
rmApplied add-cube-cbrt0.5
Applied sqrt-prod0.5
Applied div-inv0.5
Applied times-frac0.4
Applied associate-*l*0.4
Final simplification0.4
herbie shell --seed 2020024 +o rules:numerics
(FPCore (a1 a2 th)
:name "Migdal et al, Equation (64)"
:precision binary64
(+ (* (/ (cos th) (sqrt 2)) (* a1 a1)) (* (/ (cos th) (sqrt 2)) (* a2 a2))))