\[1 \le y \le 9999\]

\[\begin{array}{l} \mathbf{if}\;\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) = 0.0:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\frac{e^{\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right)} - 1}{\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right)}\\ \end{array}\]

\begin{array}{l}
\mathbf{if}\;\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) = 0.0:\\
\;\;\;\;1\\

\mathbf{else}:\\
\;\;\;\;\frac{e^{\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right)} - 1}{\left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right) \cdot \left(\left|y - \sqrt{y \cdot y + 1}\right| - \frac{1}{y + \sqrt{y \cdot y + 1}}\right)}\\

\end{array}

double f(double y) {
        double r8138 = y;
        double r8139 = r8138 * r8138;
        double r8140 = 1.0;
        double r8141 = r8139 + r8140;
        double r8142 = sqrt(r8141);
        double r8143 = r8138 - r8142;
        double r8144 = fabs(r8143);
        double r8145 = r8138 + r8142;
        double r8146 = r8140 / r8145;
        double r8147 = r8144 - r8146;
        double r8148 = r8147 * r8147;
        double r8149 = 0.0;
        double r8150 = r8148 == r8149;
        double r8151 = exp(r8148);
        double r8152 = r8151 - r8140;
        double r8153 = r8152 / r8148;
        double r8154 = r8150 ? r8140 : r8153;
        return r8154;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (y)
  :name "Kahan's Monster"
  :pre (<= 1.0 y 9999.0)
  (if (== (* (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0))))) (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0)))))) 0.0) 1.0 (/ (- (exp (* (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0))))) (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0))))))) 1.0) (* (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0))))) (- (fabs (- y (sqrt (+ (* y y) 1.0)))) (/ 1.0 (+ y (sqrt (+ (* y y) 1.0)))))))))

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

could not determine a ground truth for program body (more)

Reproduce

Backtrace