\[\left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right) \land \left(0 \leq s \land s \leq 1.0651631\right)\]

\[\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - \frac{1}{1 + e^{\frac{\pi}{s}}}\right) + \frac{1}{1 + e^{\frac{\pi}{s}}}} - 1\right) \]

(FPCore (u s)
 :precision binary32
 (*
  (- s)
  (log
   (-
    (/
     1.0
     (+
      (*
       u
       (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) (/ 1.0 (+ 1.0 (exp (/ PI s))))))
      (/ 1.0 (+ 1.0 (exp (/ PI s))))))
    1.0))))

float code(float u, float s) {
	return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - (1.0f / (1.0f + expf((((float) M_PI) / s)))))) + (1.0f / (1.0f + expf((((float) M_PI) / s)))))) - 1.0f));
}

function code(u, s)
	return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))))) + Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))))) - Float32(1.0))))
end

function tmp = code(u, s)
	tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - (single(1.0) / (single(1.0) + exp((single(pi) / s)))))) + (single(1.0) / (single(1.0) + exp((single(pi) / s)))))) - single(1.0)));
end

\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - \frac{1}{1 + e^{\frac{\pi}{s}}}\right) + \frac{1}{1 + e^{\frac{\pi}{s}}}} - 1\right)

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2022204 
(FPCore (u s)
  :name "Sample trimmed logistic on [-pi, pi]"
  :precision binary32
  :pre (and (and (<= 2.328306437e-10 u) (<= u 1.0)) (and (<= 0.0 s) (<= s 1.0651631)))
  (* (- s) (log (- (/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) 1.0))))

Backtrace

nan?: contract violation expected: real? given: 0.5000000000000001+0.8660254037844386i		L	C
simplify-node*	/data/pavpan/nightlies/herbie/fix-inf-exact/src/core/reduce.rkt	61	0
hash-ref!	/usr/share/racket/collects/racket/private/more-scheme.rkt	377	2
hash-ref!	/usr/share/racket/collects/racket/private/more-scheme.rkt	377	2
loop	.../private/map.rkt	40	19
f22	.../match/compiler.rkt	548	40
hash-ref!	/usr/share/racket/collects/racket/private/more-scheme.rkt	377	2
approximate	/data/pavpan/nightlies/herbie/fix-inf-exact/src/core/taylor.rkt	7	0
taylor-expr	/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt	78	0
taylor-alt	/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt	85	0
gen-series!	/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt	101	0
patch-table-run	/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt	310	0
(unnamed)	/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt	486	18
run-iter!	/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt	242	0
mutate!	/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt	348	0
run-improve!	/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt	296	0
(unnamed)	/data/pavpan/nightlies/herbie/fix-inf-exact/src/sandbox.rkt	55	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