\[\frac{\pi}{\sin \left(\pi \cdot z\right)} \cdot \left(\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}^{\left(\left(\left(1 - z\right) - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)\]
\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(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)
double f(double z) {
        double r51699 = atan2(1.0, 0.0);
        double r51700 = z;
        double r51701 = r51699 * r51700;
        double r51702 = sin(r51701);
        double r51703 = r51699 / r51702;
        double r51704 = 2.0;
        double r51705 = r51699 * r51704;
        double r51706 = sqrt(r51705);
        double r51707 = 1.0;
        double r51708 = r51707 - r51700;
        double r51709 = r51708 - r51707;
        double r51710 = 7.0;
        double r51711 = r51709 + r51710;
        double r51712 = 0.5;
        double r51713 = r51711 + r51712;
        double r51714 = r51709 + r51712;
        double r51715 = pow(r51713, r51714);
        double r51716 = r51706 * r51715;
        double r51717 = -r51713;
        double r51718 = exp(r51717);
        double r51719 = r51716 * r51718;
        double r51720 = 0.9999999999998099;
        double r51721 = 676.5203681218851;
        double r51722 = r51709 + r51707;
        double r51723 = r51721 / r51722;
        double r51724 = r51720 + r51723;
        double r51725 = -1259.1392167224028;
        double r51726 = r51709 + r51704;
        double r51727 = r51725 / r51726;
        double r51728 = r51724 + r51727;
        double r51729 = 771.3234287776531;
        double r51730 = 3.0;
        double r51731 = r51709 + r51730;
        double r51732 = r51729 / r51731;
        double r51733 = r51728 + r51732;
        double r51734 = -176.6150291621406;
        double r51735 = 4.0;
        double r51736 = r51709 + r51735;
        double r51737 = r51734 / r51736;
        double r51738 = r51733 + r51737;
        double r51739 = 12.507343278686905;
        double r51740 = 5.0;
        double r51741 = r51709 + r51740;
        double r51742 = r51739 / r51741;
        double r51743 = r51738 + r51742;
        double r51744 = -0.13857109526572012;
        double r51745 = 6.0;
        double r51746 = r51709 + r51745;
        double r51747 = r51744 / r51746;
        double r51748 = r51743 + r51747;
        double r51749 = 9.984369578019572e-06;
        double r51750 = r51749 / r51711;
        double r51751 = r51748 + r51750;
        double r51752 = 1.5056327351493116e-07;
        double r51753 = 8.0;
        double r51754 = r51709 + r51753;
        double r51755 = r51752 / r51754;
        double r51756 = r51751 + r51755;
        double r51757 = r51719 * r51756;
        double r51758 = r51703 * r51757;
        return r51758;
}

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

get-representation: Unknown representation #fLC
(unnamed)/data/pavpan/nightlies/herbie/js-tweaks/src/core/localize.rkt2313
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
map/opt/racket-7.0/collects/racket/private/map.rkt3513
parse-loop30/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
map/opt/racket-7.0/collects/racket/private/map.rkt3513
parse-loop30/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
map/opt/racket-7.0/collects/racket/private/map.rkt3513
parse-loop30/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
map/opt/racket-7.0/collects/racket/private/map.rkt3513
parse-loop30/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
localize-error/data/pavpan/nightlies/herbie/js-tweaks/src/core/localize.rkt610
localize!/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt1230
run-iter!/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt3230
for-loop/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt3594
run-improve47/data/pavpan/nightlies/herbie/js-tweaks/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