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

\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 r163901 = NdChar;
        double r163902 = 1.0;
        double r163903 = Ec;
        double r163904 = Vef;
        double r163905 = r163903 - r163904;
        double r163906 = EDonor;
        double r163907 = r163905 - r163906;
        double r163908 = mu;
        double r163909 = r163907 - r163908;
        double r163910 = -r163909;
        double r163911 = KbT;
        double r163912 = r163910 / r163911;
        double r163913 = exp(r163912);
        double r163914 = r163902 + r163913;
        double r163915 = r163901 / r163914;
        double r163916 = NaChar;
        double r163917 = Ev;
        double r163918 = r163917 + r163904;
        double r163919 = EAccept;
        double r163920 = r163918 + r163919;
        double r163921 = -r163908;
        double r163922 = r163920 + r163921;
        double r163923 = r163922 / r163911;
        double r163924 = exp(r163923);
        double r163925 = r163902 + r163924;
        double r163926 = r163916 / r163925;
        double r163927 = r163915 + r163926;
        return r163927;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020045 
(FPCore (NdChar Ec Vef EDonor mu KbT NaChar Ev EAccept)
  :name "Bulmash initializePoisson"
  :precision binary64
  (+ (/ NdChar (+ 1 (exp (/ (- (- (- (- Ec Vef) EDonor) mu)) KbT)))) (/ NaChar (+ 1 (exp (/ (+ (+ (+ Ev Vef) EAccept) (- mu)) KbT))))))

Backtrace

hash-ref: no value found for key key: '(* #<enode 8(559)> #<enode 38(3425)>)		L	C
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/egraph.rkt	270	6
update-leader!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/egraph.rkt	265	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/main.rkt	77	2
prune-phase	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/main.rkt	74	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	80	4
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	76	2
(unnamed)	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	56	0
(unnamed)	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	38	0
simplify!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	224	0
run-iter!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	327	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	365	4
run-improve47	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	346	0
.../more-scheme.rkt:261:28	unknown
run	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.5/collects/racket/private/more-scheme.rkt	261	28

Falling back on racket egraph because egg-herbie package not installed (more)

Reproduce

Backtrace