\frac{2}{e^{x} + e^{-x}}
\frac{-2}{\frac{-1}{e^{x}} - e^{x}}
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
(FPCore (x) :precision binary64 (/ -2.0 (- (/ -1.0 (exp x)) (exp x))))
double code(double x) {
return 2.0 / (exp(x) + exp(-x));
}
double code(double x) {
return -2.0 / ((-1.0 / exp(x)) - exp(x));
}



Bits error versus x
Results
Initial program 0.0
Applied frac-2neg_binary640.0
Simplified0.0
Simplified0.0
Final simplification0.0
herbie shell --seed 2021215
(FPCore (x)
:name "Hyperbolic secant"
:precision binary64
(/ 2.0 (+ (exp x) (exp (- x)))))