\[0 < c_p \land 0 < c_n\]

\[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c_n}}\]

\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c_n}}

(FPCore (c_p c_n t s)
 :precision binary64
 (/
  (*
   (pow (/ 1.0 (+ 1.0 (exp (- s)))) c_p)
   (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- s))))) c_n))
  (*
   (pow (/ 1.0 (+ 1.0 (exp (- t)))) c_p)
   (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))))

double code(double c_p, double c_n, double t, double s) {
	return (pow((1.0 / (1.0 + exp(-s))), c_p) * pow((1.0 - (1.0 / (1.0 + exp(-s)))), c_n)) / (pow((1.0 / (1.0 + exp(-t))), c_p) * pow((1.0 - (1.0 / (1.0 + exp(-t)))), c_n));
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2021067 
(FPCore (c_p c_n t s)
  :name "Harley's example"
  :precision binary64
  :pre (and (< 0.0 c_p) (< 0.0 c_n))

  :herbie-target
  (* (pow (/ (+ 1.0 (exp (- t))) (+ 1.0 (exp (- s)))) c_p) (pow (/ (+ 1.0 (exp t)) (+ 1.0 (exp s))) c_n))

  (/ (* (pow (/ 1.0 (+ 1.0 (exp (- s)))) c_p) (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- s))))) c_n)) (* (pow (/ 1.0 (+ 1.0 (exp (- t)))) c_p) (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))))

Backtrace

simplify-batch: contract violation expected keyword argument #:precompute in: (-> (listof (or/c (listof any/c) symbol? value? real?)) #:precompute boolean? #:rules (listof rule?) (listof (listof (or/c (listof any/c) symbol? value? real?)))) contract from: (function simplify-batch) blaming: <pkgs>/herbie/core/simplify.rkt (assuming the contract is correct) at: <pkgs>/herbie/core/simplify.rkt:68.18		L	C
raise-blame-error	/opt/racket-7.9/collects/racket/contract/private/blame.rkt	347	0
for-loop	/opt/racket-7.9/collects/racket/contract/private/arrow-higher-order.rkt	508	13
kwd-checker	/opt/racket-7.9/collects/racket/contract/private/arrow-higher-order.rkt	496	11
connected-components	/data/pavpan/nightlies/herbie/egg-interface-fixes/src/symmetry.rkt	17	0
run-improve	/data/pavpan/nightlies/herbie/egg-interface-fixes/src/mainloop.rkt	387	0
(unnamed)	/data/pavpan/nightlies/herbie/egg-interface-fixes/src/sandbox.rkt	54	6
run	/opt/racket-7.9/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk	/opt/racket-7.9/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.9/collects/racket/engine.rkt	42	24