\[\frac{\pi}{\sin \left(\pi \cdot z\right)} \cdot \left(\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}^{\left(\left(\left(1 - z\right) - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.99999999999980993 + \frac{676.520368121885099}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.13921672240281}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.32342877765313}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.615029162140587}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.5073432786869052}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.138571095265720118}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.98436957801957158 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.50563273514931162 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)\]
\frac{\pi}{\sin \left(\pi \cdot z\right)} \cdot \left(\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}^{\left(\left(\left(1 - z\right) - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.99999999999980993 + \frac{676.520368121885099}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.13921672240281}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.32342877765313}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.615029162140587}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.5073432786869052}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.138571095265720118}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.98436957801957158 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.50563273514931162 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)
double f(double z) {
        double r8313 = atan2(1.0, 0.0);
        double r8314 = z;
        double r8315 = r8313 * r8314;
        double r8316 = sin(r8315);
        double r8317 = r8313 / r8316;
        double r8318 = 2.0;
        double r8319 = r8313 * r8318;
        double r8320 = sqrt(r8319);
        double r8321 = 1.0;
        double r8322 = r8321 - r8314;
        double r8323 = r8322 - r8321;
        double r8324 = 7.0;
        double r8325 = r8323 + r8324;
        double r8326 = 0.5;
        double r8327 = r8325 + r8326;
        double r8328 = r8323 + r8326;
        double r8329 = pow(r8327, r8328);
        double r8330 = r8320 * r8329;
        double r8331 = -r8327;
        double r8332 = exp(r8331);
        double r8333 = r8330 * r8332;
        double r8334 = 0.9999999999998099;
        double r8335 = 676.5203681218851;
        double r8336 = r8323 + r8321;
        double r8337 = r8335 / r8336;
        double r8338 = r8334 + r8337;
        double r8339 = -1259.1392167224028;
        double r8340 = r8323 + r8318;
        double r8341 = r8339 / r8340;
        double r8342 = r8338 + r8341;
        double r8343 = 771.3234287776531;
        double r8344 = 3.0;
        double r8345 = r8323 + r8344;
        double r8346 = r8343 / r8345;
        double r8347 = r8342 + r8346;
        double r8348 = -176.6150291621406;
        double r8349 = 4.0;
        double r8350 = r8323 + r8349;
        double r8351 = r8348 / r8350;
        double r8352 = r8347 + r8351;
        double r8353 = 12.507343278686905;
        double r8354 = 5.0;
        double r8355 = r8323 + r8354;
        double r8356 = r8353 / r8355;
        double r8357 = r8352 + r8356;
        double r8358 = -0.13857109526572012;
        double r8359 = 6.0;
        double r8360 = r8323 + r8359;
        double r8361 = r8358 / r8360;
        double r8362 = r8357 + r8361;
        double r8363 = 9.984369578019572e-06;
        double r8364 = r8363 / r8325;
        double r8365 = r8362 + r8364;
        double r8366 = 1.5056327351493116e-07;
        double r8367 = 8.0;
        double r8368 = r8323 + r8367;
        double r8369 = r8366 / r8368;
        double r8370 = r8365 + r8369;
        double r8371 = r8333 * r8370;
        double r8372 = r8317 * r8371;
        return r8372;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019194 
(FPCore (z)
  :name "Jmat.Real.gamma, branch z less than 0.5"
  (* (/ PI (sin (* PI z))) (* (* (* (sqrt (* PI 2.0)) (pow (+ (+ (- (- 1.0 z) 1.0) 7.0) 0.5) (+ (- (- 1.0 z) 1.0) 0.5))) (exp (- (+ (+ (- (- 1.0 z) 1.0) 7.0) 0.5)))) (+ (+ (+ (+ (+ (+ (+ (+ 0.9999999999998099 (/ 676.5203681218851 (+ (- (- 1.0 z) 1.0) 1.0))) (/ -1259.1392167224028 (+ (- (- 1.0 z) 1.0) 2.0))) (/ 771.3234287776531 (+ (- (- 1.0 z) 1.0) 3.0))) (/ -176.6150291621406 (+ (- (- 1.0 z) 1.0) 4.0))) (/ 12.507343278686905 (+ (- (- 1.0 z) 1.0) 5.0))) (/ -0.13857109526572012 (+ (- (- 1.0 z) 1.0) 6.0))) (/ 9.984369578019572e-06 (+ (- (- 1.0 z) 1.0) 7.0))) (/ 1.5056327351493116e-07 (+ (- (- 1.0 z) 1.0) 8.0))))))

Backtrace

result arity mismatch; expected number of values not received expected: 2 received: 1 in: local-binding form values...: 0LC
loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/extraction.rkt252
(unnamed)/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt260
simplify!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt2200
run-improve47/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3420
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.0/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.0/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128