\[\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}^{\left(\left(z - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(z - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(z - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(z - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(z - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(z - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(z - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(z - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(z - 1\right) + 8}\right)\]
\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}^{\left(\left(z - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(z - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(z - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(z - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(z - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(z - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(z - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(z - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(z - 1\right) + 8}\right)
double f(double z) {
        double r84624 = atan2(1.0, 0.0);
        double r84625 = 2.0;
        double r84626 = r84624 * r84625;
        double r84627 = sqrt(r84626);
        double r84628 = z;
        double r84629 = 1.0;
        double r84630 = r84628 - r84629;
        double r84631 = 7.0;
        double r84632 = r84630 + r84631;
        double r84633 = 0.5;
        double r84634 = r84632 + r84633;
        double r84635 = r84630 + r84633;
        double r84636 = pow(r84634, r84635);
        double r84637 = r84627 * r84636;
        double r84638 = -r84634;
        double r84639 = exp(r84638);
        double r84640 = r84637 * r84639;
        double r84641 = 0.9999999999998099;
        double r84642 = 676.5203681218851;
        double r84643 = r84630 + r84629;
        double r84644 = r84642 / r84643;
        double r84645 = r84641 + r84644;
        double r84646 = -1259.1392167224028;
        double r84647 = r84630 + r84625;
        double r84648 = r84646 / r84647;
        double r84649 = r84645 + r84648;
        double r84650 = 771.3234287776531;
        double r84651 = 3.0;
        double r84652 = r84630 + r84651;
        double r84653 = r84650 / r84652;
        double r84654 = r84649 + r84653;
        double r84655 = -176.6150291621406;
        double r84656 = 4.0;
        double r84657 = r84630 + r84656;
        double r84658 = r84655 / r84657;
        double r84659 = r84654 + r84658;
        double r84660 = 12.507343278686905;
        double r84661 = 5.0;
        double r84662 = r84630 + r84661;
        double r84663 = r84660 / r84662;
        double r84664 = r84659 + r84663;
        double r84665 = -0.13857109526572012;
        double r84666 = 6.0;
        double r84667 = r84630 + r84666;
        double r84668 = r84665 / r84667;
        double r84669 = r84664 + r84668;
        double r84670 = 9.984369578019572e-06;
        double r84671 = r84670 / r84632;
        double r84672 = r84669 + r84671;
        double r84673 = 1.5056327351493116e-07;
        double r84674 = 8.0;
        double r84675 = r84630 + r84674;
        double r84676 = r84673 / r84675;
        double r84677 = r84672 + r84676;
        double r84678 = r84640 * r84677;
        return r84678;
}

Reproduce

Please include this information when filing a bug report:

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