\[\left(e^{x} - 2\right) + e^{-x}\]

\left(e^{x} - 2\right) + e^{-x}

double f(double x) {
        double r8218 = x;
        double r8219 = exp(r8218);
        double r8220 = 2.0;
        double r8221 = r8219 - r8220;
        double r8222 = -r8218;
        double r8223 = exp(r8222);
        double r8224 = r8221 + r8223;
        return r8224;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019194 +o rules:numerics
(FPCore (x)
  :name "exp2 (problem 3.3.7)"

  :herbie-target
  (* 4.0 (pow (sinh (/ x 2.0)) 2.0))

  (+ (- (exp x) 2.0) (exp (- x))))

Backtrace

result arity mismatch; expected number of values not received expected: 2 received: 1 in: local-binding form values...: 0		L	C
loop	/data/pavpan/nightlies/herbie/various-cleanup/src/core/extraction.rkt	25	2
(unnamed)	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	26	0
simplify!	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	220	0
run-improve47	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	342	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