?

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

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

(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));
}

real(8) function code(c_p, c_n, t, s)
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    code = (((1.0d0 / (1.0d0 + exp(-s))) ** c_p) * ((1.0d0 - (1.0d0 / (1.0d0 + exp(-s)))) ** c_n)) / (((1.0d0 / (1.0d0 + exp(-t))) ** c_p) * ((1.0d0 - (1.0d0 / (1.0d0 + exp(-t)))) ** c_n))
end function

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

def code(c_p, c_n, t, s):
	return (math.pow((1.0 / (1.0 + math.exp(-s))), c_p) * math.pow((1.0 - (1.0 / (1.0 + math.exp(-s)))), c_n)) / (math.pow((1.0 / (1.0 + math.exp(-t))), c_p) * math.pow((1.0 - (1.0 / (1.0 + math.exp(-t)))), c_n))

function code(c_p, c_n, t, s)
	return Float64(Float64((Float64(1.0 / Float64(1.0 + exp(Float64(-s)))) ^ c_p) * (Float64(1.0 - Float64(1.0 / Float64(1.0 + exp(Float64(-s))))) ^ c_n)) / Float64((Float64(1.0 / Float64(1.0 + exp(Float64(-t)))) ^ c_p) * (Float64(1.0 - Float64(1.0 / Float64(1.0 + exp(Float64(-t))))) ^ c_n)))
end

function tmp = code(c_p, c_n, t, s)
	tmp = (((1.0 / (1.0 + exp(-s))) ^ c_p) * ((1.0 - (1.0 / (1.0 + exp(-s)))) ^ c_n)) / (((1.0 / (1.0 + exp(-t))) ^ c_p) * ((1.0 - (1.0 / (1.0 + exp(-t)))) ^ c_n));
end

code[c$95$p_, c$95$n_, t_, s_] := N[(N[(N[Power[N[(1.0 / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision] * N[Power[N[(1.0 - N[(1.0 / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision] / N[(N[Power[N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision] * N[Power[N[(1.0 - N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

\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}}

Reproduce?

Please include this information when filing a bug report:

herbie shell --seed 2023243 
(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

arb-<: arity mismatch; the expected number of arguments does not match the given number expected: 0 given: 2		L	C
f	/home/nightlies/herbie/arb-support/src/programs.rkt	187	2
(unnamed)	/home/nightlies/herbie/arb-support/src/ground-truth.rkt	23	2
search-step	/home/nightlies/herbie/arb-support/src/searchreals.rkt	37	0
find-intervals	/home/nightlies/herbie/arb-support/src/searchreals.rkt	87	0
make-sampler	/home/nightlies/herbie/arb-support/src/sampling.rkt	94	0
sample-points	/home/nightlies/herbie/arb-support/src/ground-truth.rkt	64	0
setup-context!	/home/nightlies/herbie/arb-support/src/mainloop.rkt	293	0
get-alternatives/report	/home/nightlies/herbie/arb-support/src/sandbox.rkt	148	0
(unnamed)	/home/nightlies/herbie/arb-support/src/sandbox.rkt	247	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24