\[\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\left(1 + \varepsilon\right) \cdot x}}{2}\]
\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\left(1 + \varepsilon\right) \cdot x}}{2}
double f(double x, double eps) {
        double r4554861 = 1.0;
        double r4554862 = eps;
        double r4554863 = r4554861 / r4554862;
        double r4554864 = r4554861 + r4554863;
        double r4554865 = r4554861 - r4554862;
        double r4554866 = x;
        double r4554867 = r4554865 * r4554866;
        double r4554868 = -r4554867;
        double r4554869 = exp(r4554868);
        double r4554870 = r4554864 * r4554869;
        double r4554871 = r4554863 - r4554861;
        double r4554872 = r4554861 + r4554862;
        double r4554873 = r4554872 * r4554866;
        double r4554874 = -r4554873;
        double r4554875 = exp(r4554874);
        double r4554876 = r4554871 * r4554875;
        double r4554877 = r4554870 - r4554876;
        double r4554878 = 2.0;
        double r4554879 = r4554877 / r4554878;
        return r4554879;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 
(FPCore (x eps)
  :name "NMSE Section 6.1 mentioned, A"
  (/ (- (* (+ 1.0 (/ 1.0 eps)) (exp (- (* (- 1.0 eps) x)))) (* (- (/ 1.0 eps) 1.0) (exp (- (* (+ 1.0 eps) x))))) 2.0))

Backtrace

hash-ref: no value found for key key: #<enode 496(496)>LC
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt1972
extractor-extract/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt1960
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt352
(unnamed)/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt260
simplify!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt2170
run-iter!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3200
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3544
run-improve43/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3390
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.0/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.0/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128