\[\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}^{\left(\left(z - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(z - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(z - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(z - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(z - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(z - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(z - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(z - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(z - 1\right) + 8}\right)\]

\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 r8673 = atan2(1.0, 0.0);
        double r8674 = 2.0;
        double r8675 = r8673 * r8674;
        double r8676 = sqrt(r8675);
        double r8677 = z;
        double r8678 = 1.0;
        double r8679 = r8677 - r8678;
        double r8680 = 7.0;
        double r8681 = r8679 + r8680;
        double r8682 = 0.5;
        double r8683 = r8681 + r8682;
        double r8684 = r8679 + r8682;
        double r8685 = pow(r8683, r8684);
        double r8686 = r8676 * r8685;
        double r8687 = -r8683;
        double r8688 = exp(r8687);
        double r8689 = r8686 * r8688;
        double r8690 = 0.9999999999998099;
        double r8691 = 676.5203681218851;
        double r8692 = r8679 + r8678;
        double r8693 = r8691 / r8692;
        double r8694 = r8690 + r8693;
        double r8695 = -1259.1392167224028;
        double r8696 = r8679 + r8674;
        double r8697 = r8695 / r8696;
        double r8698 = r8694 + r8697;
        double r8699 = 771.3234287776531;
        double r8700 = 3.0;
        double r8701 = r8679 + r8700;
        double r8702 = r8699 / r8701;
        double r8703 = r8698 + r8702;
        double r8704 = -176.6150291621406;
        double r8705 = 4.0;
        double r8706 = r8679 + r8705;
        double r8707 = r8704 / r8706;
        double r8708 = r8703 + r8707;
        double r8709 = 12.507343278686905;
        double r8710 = 5.0;
        double r8711 = r8679 + r8710;
        double r8712 = r8709 / r8711;
        double r8713 = r8708 + r8712;
        double r8714 = -0.13857109526572012;
        double r8715 = 6.0;
        double r8716 = r8679 + r8715;
        double r8717 = r8714 / r8716;
        double r8718 = r8713 + r8717;
        double r8719 = 9.984369578019572e-06;
        double r8720 = r8719 / r8681;
        double r8721 = r8718 + r8720;
        double r8722 = 1.5056327351493116e-07;
        double r8723 = 8.0;
        double r8724 = r8679 + r8723;
        double r8725 = r8722 / r8724;
        double r8726 = r8721 + r8725;
        double r8727 = r8689 * r8726;
        return r8727;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(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 #f		L	C
loop	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	122	4
prepare-points	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	146	0
setup-prog!34	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	67	0
run-improve43	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	339	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28