\frac{2}{e^{x} + e^{-x}}
\sqrt{\frac{\frac{2}{e^{x} + e^{-x}}}{\cosh x}}
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
(FPCore (x) :precision binary64 (sqrt (/ (/ 2.0 (+ (exp x) (exp (- x)))) (cosh x))))
double code(double x) {
return 2.0 / (exp(x) + exp(-x));
}
double code(double x) {
return sqrt((2.0 / (exp(x) + exp(-x))) / cosh(x));
}



Bits error versus x
Results
Initial program 0.0
Applied add-sqr-sqrt_binary640.8
Applied add-sqr-sqrt_binary640.0
Applied times-frac_binary640.0
Applied sqrt-undiv_binary640.0
Applied sqrt-undiv_binary640.0
Applied sqrt-unprod_binary640.0
Simplified0.0
Final simplification0.0
herbie shell --seed 2022088
(FPCore (x)
:name "Hyperbolic secant"
:precision binary64
(/ 2.0 (+ (exp x) (exp (- x)))))