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



Bits error versus x
Results
Initial program 0.0
rmApplied add-sqr-sqrt_binary64_28280.8
Applied associate-/r*_binary64_27500.5
rmApplied cosh-undef_binary64_30000.5
Applied sqrt-prod_binary64_28220.5
Applied add-sqr-sqrt_binary64_28280.5
Applied times-frac_binary64_28120.0
Simplified0.0
Final simplification0.0
herbie shell --seed 2021050
(FPCore (x)
:name "Hyperbolic secant"
:precision binary64
(/ 2.0 (+ (exp x) (exp (- x)))))