\[\left(\left(\sqrt{\pi \cdot 2.0} \cdot {\left(\left(\left(z - 1.0\right) + 7.0\right) + 0.5\right)}^{\left(\left(z - 1.0\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1.0\right) + 7.0\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099 + \frac{676.5203681218851}{\left(z - 1.0\right) + 1.0}\right) + \frac{-1259.1392167224028}{\left(z - 1.0\right) + 2.0}\right) + \frac{771.3234287776531}{\left(z - 1.0\right) + 3.0}\right) + \frac{-176.6150291621406}{\left(z - 1.0\right) + 4.0}\right) + \frac{12.507343278686905}{\left(z - 1.0\right) + 5.0}\right) + \frac{-0.13857109526572012}{\left(z - 1.0\right) + 6.0}\right) + \frac{9.984369578019572 \cdot 10^{-06}}{\left(z - 1.0\right) + 7.0}\right) + \frac{1.5056327351493116 \cdot 10^{-07}}{\left(z - 1.0\right) + 8.0}\right)\]
\left(\left(\sqrt{\pi \cdot 2.0} \cdot {\left(\left(\left(z - 1.0\right) + 7.0\right) + 0.5\right)}^{\left(\left(z - 1.0\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1.0\right) + 7.0\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099 + \frac{676.5203681218851}{\left(z - 1.0\right) + 1.0}\right) + \frac{-1259.1392167224028}{\left(z - 1.0\right) + 2.0}\right) + \frac{771.3234287776531}{\left(z - 1.0\right) + 3.0}\right) + \frac{-176.6150291621406}{\left(z - 1.0\right) + 4.0}\right) + \frac{12.507343278686905}{\left(z - 1.0\right) + 5.0}\right) + \frac{-0.13857109526572012}{\left(z - 1.0\right) + 6.0}\right) + \frac{9.984369578019572 \cdot 10^{-06}}{\left(z - 1.0\right) + 7.0}\right) + \frac{1.5056327351493116 \cdot 10^{-07}}{\left(z - 1.0\right) + 8.0}\right)
double f(double z) {
        double r3383846 = atan2(1.0, 0.0);
        double r3383847 = 2.0;
        double r3383848 = r3383846 * r3383847;
        double r3383849 = sqrt(r3383848);
        double r3383850 = z;
        double r3383851 = 1.0;
        double r3383852 = r3383850 - r3383851;
        double r3383853 = 7.0;
        double r3383854 = r3383852 + r3383853;
        double r3383855 = 0.5;
        double r3383856 = r3383854 + r3383855;
        double r3383857 = r3383852 + r3383855;
        double r3383858 = pow(r3383856, r3383857);
        double r3383859 = r3383849 * r3383858;
        double r3383860 = -r3383856;
        double r3383861 = exp(r3383860);
        double r3383862 = r3383859 * r3383861;
        double r3383863 = 0.9999999999998099;
        double r3383864 = 676.5203681218851;
        double r3383865 = r3383852 + r3383851;
        double r3383866 = r3383864 / r3383865;
        double r3383867 = r3383863 + r3383866;
        double r3383868 = -1259.1392167224028;
        double r3383869 = r3383852 + r3383847;
        double r3383870 = r3383868 / r3383869;
        double r3383871 = r3383867 + r3383870;
        double r3383872 = 771.3234287776531;
        double r3383873 = 3.0;
        double r3383874 = r3383852 + r3383873;
        double r3383875 = r3383872 / r3383874;
        double r3383876 = r3383871 + r3383875;
        double r3383877 = -176.6150291621406;
        double r3383878 = 4.0;
        double r3383879 = r3383852 + r3383878;
        double r3383880 = r3383877 / r3383879;
        double r3383881 = r3383876 + r3383880;
        double r3383882 = 12.507343278686905;
        double r3383883 = 5.0;
        double r3383884 = r3383852 + r3383883;
        double r3383885 = r3383882 / r3383884;
        double r3383886 = r3383881 + r3383885;
        double r3383887 = -0.13857109526572012;
        double r3383888 = 6.0;
        double r3383889 = r3383852 + r3383888;
        double r3383890 = r3383887 / r3383889;
        double r3383891 = r3383886 + r3383890;
        double r3383892 = 9.984369578019572e-06;
        double r3383893 = r3383892 / r3383854;
        double r3383894 = r3383891 + r3383893;
        double r3383895 = 1.5056327351493116e-07;
        double r3383896 = 8.0;
        double r3383897 = r3383852 + r3383896;
        double r3383898 = r3383895 / r3383897;
        double r3383899 = r3383894 + r3383898;
        double r3383900 = r3383862 * r3383899;
        return r3383900;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019165 +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

->bf: contract violation expected: value? given: 'PI in: the 1st argument of (-> value? bigvalue?) contract from: (function ->bf) blaming: /data/pavpan/nightlies/herbie/optional-posits/src/float.rkt (assuming the contract is correct) at: /data/pavpan/nightlies/herbie/optional-posits/src/float.rkt:163.18LC
raise-blame-error16/opt/racket-7.0/collects/racket/contract/private/blame.rkt3470
(unnamed)/opt/racket-7.0/collects/racket/contract/private/arrow-higher-order.rkt35733
(unnamed)/data/pavpan/nightlies/herbie/optional-posits/src/core/localize.rkt2213
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
loop/opt/racket-7.0/collects/racket/private/map.rkt4019
parse-loop15/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
f9/opt/racket-7.0/collects/racket/match/compiler.rkt50740
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
loop/opt/racket-7.0/collects/racket/private/map.rkt4019
parse-loop15/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
loop/opt/racket-7.0/collects/racket/private/map.rkt4019
parse-loop15/opt/racket-7.0/collects/racket/match/compiler.rkt41815
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
loop/opt/racket-7.0/collects/racket/private/map.rkt4019
parse-loop15/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/optional-posits/src/core/localize.rkt520
localize!/data/pavpan/nightlies/herbie/optional-posits/src/mainloop.rkt1160
run-iter!/data/pavpan/nightlies/herbie/optional-posits/src/mainloop.rkt3170
for-loop/data/pavpan/nightlies/herbie/optional-posits/src/mainloop.rkt3514
run-improve40/data/pavpan/nightlies/herbie/optional-posits/src/mainloop.rkt3360
(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