\tan \left(x + \varepsilon\right) - \tan x
\sqrt[3]{\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}\right)} + \frac{\sin x}{\cos x} \cdot \left(\frac{1}{1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}} + -1\right)} \cdot \left(\sqrt[3]{\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}\right)} + \frac{\sin x}{\cos x} \cdot \left(\frac{1}{1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}} + -1\right)} \cdot \sqrt[3]{\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}\right)} + \frac{\sin x}{\cos x} \cdot \left(\frac{1}{1 - \frac{\sin \varepsilon \cdot \sin x}{\cos \varepsilon \cdot \cos x}} + -1\right)}\right)(FPCore (x eps) :precision binary64 (- (tan (+ x eps)) (tan x)))
(FPCore (x eps)
:precision binary64
(*
(cbrt
(+
(/
(sin eps)
(* (cos eps) (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x))))))
(*
(/ (sin x) (cos x))
(+
(/ 1.0 (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x)))))
-1.0))))
(*
(cbrt
(+
(/
(sin eps)
(* (cos eps) (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x))))))
(*
(/ (sin x) (cos x))
(+
(/ 1.0 (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x)))))
-1.0))))
(cbrt
(+
(/
(sin eps)
(* (cos eps) (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x))))))
(*
(/ (sin x) (cos x))
(+
(/ 1.0 (- 1.0 (/ (* (sin eps) (sin x)) (* (cos eps) (cos x)))))
-1.0)))))))double code(double x, double eps) {
return ((double) (((double) tan(((double) (x + eps)))) - ((double) tan(x))));
}
double code(double x, double eps) {
return ((double) (((double) cbrt(((double) ((((double) sin(eps)) / ((double) (((double) cos(eps)) * ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))))) + ((double) ((((double) sin(x)) / ((double) cos(x))) * ((double) ((1.0 / ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))) + -1.0)))))))) * ((double) (((double) cbrt(((double) ((((double) sin(eps)) / ((double) (((double) cos(eps)) * ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))))) + ((double) ((((double) sin(x)) / ((double) cos(x))) * ((double) ((1.0 / ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))) + -1.0)))))))) * ((double) cbrt(((double) ((((double) sin(eps)) / ((double) (((double) cos(eps)) * ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))))) + ((double) ((((double) sin(x)) / ((double) cos(x))) * ((double) ((1.0 / ((double) (1.0 - (((double) (((double) sin(eps)) * ((double) sin(x)))) / ((double) (((double) cos(eps)) * ((double) cos(x)))))))) + -1.0))))))))))));
}




Bits error versus x




Bits error versus eps
Results
| Original | 37.1 |
|---|---|
| Target | 15.5 |
| Herbie | 13.8 |
Initial program 37.1
rmApplied tan-sum_binary6421.5
Taylor expanded around inf 21.6
Simplified21.6
rmApplied add-cube-cbrt_binary6422.2
Simplified22.2
Simplified13.8
Final simplification13.8
herbie shell --seed 2020204
(FPCore (x eps)
:name "2tan (problem 3.3.2)"
:precision binary64
:herbie-target
(/ (sin eps) (* (cos x) (cos (+ x eps))))
(- (tan (+ x eps)) (tan x)))