\[\frac{2 + \left(\left(\sqrt{2} \cdot \left(\sin x - \frac{\sin y}{16}\right)\right) \cdot \left(\sin y - \frac{\sin x}{16}\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\sqrt{5} - 1}{2} \cdot \cos x\right) + \frac{3 - \sqrt{5}}{2} \cdot \cos y\right)}\]

\frac{2 + \left(\left(\sqrt{2} \cdot \left(\sin x - \frac{\sin y}{16}\right)\right) \cdot \left(\sin y - \frac{\sin x}{16}\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\sqrt{5} - 1}{2} \cdot \cos x\right) + \frac{3 - \sqrt{5}}{2} \cdot \cos y\right)}

double f(double x, double y) {
        double r8683 = 2.0;
        double r8684 = sqrt(r8683);
        double r8685 = x;
        double r8686 = sin(r8685);
        double r8687 = y;
        double r8688 = sin(r8687);
        double r8689 = 16.0;
        double r8690 = r8688 / r8689;
        double r8691 = r8686 - r8690;
        double r8692 = r8684 * r8691;
        double r8693 = r8686 / r8689;
        double r8694 = r8688 - r8693;
        double r8695 = r8692 * r8694;
        double r8696 = cos(r8685);
        double r8697 = cos(r8687);
        double r8698 = r8696 - r8697;
        double r8699 = r8695 * r8698;
        double r8700 = r8683 + r8699;
        double r8701 = 3.0;
        double r8702 = 1.0;
        double r8703 = 5.0;
        double r8704 = sqrt(r8703);
        double r8705 = r8704 - r8702;
        double r8706 = r8705 / r8683;
        double r8707 = r8706 * r8696;
        double r8708 = r8702 + r8707;
        double r8709 = r8701 - r8704;
        double r8710 = r8709 / r8683;
        double r8711 = r8710 * r8697;
        double r8712 = r8708 + r8711;
        double r8713 = r8701 * r8712;
        double r8714 = r8700 / r8713;
        return r8714;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x y)
  :name "Diagrams.TwoD.Path.Metafont.Internal:hobbyF from diagrams-contrib-1.3.0.5"
  (/ (+ 2.0 (* (* (* (sqrt 2.0) (- (sin x) (/ (sin y) 16.0))) (- (sin y) (/ (sin x) 16.0))) (- (cos x) (cos y)))) (* 3.0 (+ (+ 1.0 (* (/ (- (sqrt 5.0) 1.0) 2.0) (cos x))) (* (/ (- 3.0 (sqrt 5.0)) 2.0) (cos y))))))

Backtrace

get-representation: Unknown representation #f		L	C
loop	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	122	4
prepare-points	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	146	0
setup-prog!34	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	67	0
run-improve43	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	339	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28