\left(J \cdot \left(e^{\ell} - e^{-\ell}\right)\right) \cdot \cos \left(\frac{K}{2}\right) + U
\begin{array}{l}
t_0 := \cos \left(0.5 \cdot K\right)\\
\left(0.016666666666666666 \cdot \left({\ell}^{5} \cdot t_0\right) + \left(0.3333333333333333 \cdot \left(t_0 \cdot {\ell}^{3}\right) + 2 \cdot \left(\ell \cdot t_0\right)\right)\right) \cdot J + U
\end{array}
(FPCore (J l K U) :precision binary64 (+ (* (* J (- (exp l) (exp (- l)))) (cos (/ K 2.0))) U))
(FPCore (J l K U)
:precision binary64
(let* ((t_0 (cos (* 0.5 K))))
(+
(*
(+
(* 0.016666666666666666 (* (pow l 5.0) t_0))
(+ (* 0.3333333333333333 (* t_0 (pow l 3.0))) (* 2.0 (* l t_0))))
J)
U)))double code(double J, double l, double K, double U) {
return ((J * (exp(l) - exp(-l))) * cos(K / 2.0)) + U;
}
double code(double J, double l, double K, double U) {
double t_0 = cos(0.5 * K);
return (((0.016666666666666666 * (pow(l, 5.0) * t_0)) + ((0.3333333333333333 * (t_0 * pow(l, 3.0))) + (2.0 * (l * t_0)))) * J) + U;
}



Bits error versus J



Bits error versus l



Bits error versus K



Bits error versus U
Results
Initial program 17.7
Simplified17.7
Applied sinh-undef_binary640.1
Taylor expanded in l around 0 0.3
Simplified0.3
Taylor expanded in J around 0 0.3
Final simplification0.3
herbie shell --seed 2022061
(FPCore (J l K U)
:name "Maksimov and Kolovsky, Equation (4)"
:precision binary64
(+ (* (* J (- (exp l) (exp (- l)))) (cos (/ K 2.0))) U))