\[\frac{NdChar}{1 + e^{\frac{-\left(\left(\left(Ec - Vef\right) - EDonor\right) - mu\right)}{KbT}}} + \frac{NaChar}{1 + e^{\frac{\left(\left(Ev + Vef\right) + EAccept\right) + \left(-mu\right)}{KbT}}}\]

\frac{NdChar}{1 + e^{\frac{-\left(\left(\left(Ec - Vef\right) - EDonor\right) - mu\right)}{KbT}}} + \frac{NaChar}{1 + e^{\frac{\left(\left(Ev + Vef\right) + EAccept\right) + \left(-mu\right)}{KbT}}}

double f(double NdChar, double Ec, double Vef, double EDonor, double mu, double KbT, double NaChar, double Ev, double EAccept) {
        double r8686 = NdChar;
        double r8687 = 1.0;
        double r8688 = Ec;
        double r8689 = Vef;
        double r8690 = r8688 - r8689;
        double r8691 = EDonor;
        double r8692 = r8690 - r8691;
        double r8693 = mu;
        double r8694 = r8692 - r8693;
        double r8695 = -r8694;
        double r8696 = KbT;
        double r8697 = r8695 / r8696;
        double r8698 = exp(r8697);
        double r8699 = r8687 + r8698;
        double r8700 = r8686 / r8699;
        double r8701 = NaChar;
        double r8702 = Ev;
        double r8703 = r8702 + r8689;
        double r8704 = EAccept;
        double r8705 = r8703 + r8704;
        double r8706 = -r8693;
        double r8707 = r8705 + r8706;
        double r8708 = r8707 / r8696;
        double r8709 = exp(r8708);
        double r8710 = r8687 + r8709;
        double r8711 = r8701 / r8710;
        double r8712 = r8700 + r8711;
        return r8712;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 
(FPCore (NdChar Ec Vef EDonor mu KbT NaChar Ev EAccept)
  :name "Bulmash initializePoisson"
  (+ (/ NdChar (+ 1.0 (exp (/ (- (- (- (- Ec Vef) EDonor) mu)) KbT)))) (/ NaChar (+ 1.0 (exp (/ (+ (+ (+ Ev Vef) EAccept) (- mu)) KbT))))))

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