\[\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}^{\left(\left(z - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(z - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.9999999999998099298181841732002794742584 + \frac{676.5203681218850988443591631948947906494}{\left(z - 1\right) + 1}\right) + \frac{-1259.139216722402807135949842631816864014}{\left(z - 1\right) + 2}\right) + \frac{771.3234287776531346025876700878143310547}{\left(z - 1\right) + 3}\right) + \frac{-176.6150291621405870046146446838974952698}{\left(z - 1\right) + 4}\right) + \frac{12.50734327868690520801919774385169148445}{\left(z - 1\right) + 5}\right) + \frac{-0.1385710952657201178173096423051902092993}{\left(z - 1\right) + 6}\right) + \frac{9.984369578019571583242346146658263705831 \cdot 10^{-6}}{\left(z - 1\right) + 7}\right) + \frac{1.505632735149311617592788074479481785772 \cdot 10^{-7}}{\left(z - 1\right) + 8}\right)\]
\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 r8487 = atan2(1.0, 0.0);
        double r8488 = 2.0;
        double r8489 = r8487 * r8488;
        double r8490 = sqrt(r8489);
        double r8491 = z;
        double r8492 = 1.0;
        double r8493 = r8491 - r8492;
        double r8494 = 7.0;
        double r8495 = r8493 + r8494;
        double r8496 = 0.5;
        double r8497 = r8495 + r8496;
        double r8498 = r8493 + r8496;
        double r8499 = pow(r8497, r8498);
        double r8500 = r8490 * r8499;
        double r8501 = -r8497;
        double r8502 = exp(r8501);
        double r8503 = r8500 * r8502;
        double r8504 = 0.9999999999998099;
        double r8505 = 676.5203681218851;
        double r8506 = r8493 + r8492;
        double r8507 = r8505 / r8506;
        double r8508 = r8504 + r8507;
        double r8509 = -1259.1392167224028;
        double r8510 = r8493 + r8488;
        double r8511 = r8509 / r8510;
        double r8512 = r8508 + r8511;
        double r8513 = 771.3234287776531;
        double r8514 = 3.0;
        double r8515 = r8493 + r8514;
        double r8516 = r8513 / r8515;
        double r8517 = r8512 + r8516;
        double r8518 = -176.6150291621406;
        double r8519 = 4.0;
        double r8520 = r8493 + r8519;
        double r8521 = r8518 / r8520;
        double r8522 = r8517 + r8521;
        double r8523 = 12.507343278686905;
        double r8524 = 5.0;
        double r8525 = r8493 + r8524;
        double r8526 = r8523 / r8525;
        double r8527 = r8522 + r8526;
        double r8528 = -0.13857109526572012;
        double r8529 = 6.0;
        double r8530 = r8493 + r8529;
        double r8531 = r8528 / r8530;
        double r8532 = r8527 + r8531;
        double r8533 = 9.984369578019572e-06;
        double r8534 = r8533 / r8495;
        double r8535 = r8532 + r8534;
        double r8536 = 1.5056327351493116e-07;
        double r8537 = 8.0;
        double r8538 = r8493 + r8537;
        double r8539 = r8536 / r8538;
        double r8540 = r8535 + r8539;
        double r8541 = r8503 * r8540;
        return r8541;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019305 
(FPCore (z)
  :name "Jmat.Real.gamma, branch z greater than 0.5"
  :precision binary64
  (* (* (* (sqrt (* PI 2)) (pow (+ (+ (- z 1) 7) 0.5) (+ (- z 1) 0.5))) (exp (- (+ (+ (- z 1) 7) 0.5)))) (+ (+ (+ (+ (+ (+ (+ (+ 0.99999999999980993 (/ 676.520368121885099 (+ (- z 1) 1))) (/ -1259.13921672240281 (+ (- z 1) 2))) (/ 771.32342877765313 (+ (- z 1) 3))) (/ -176.615029162140587 (+ (- z 1) 4))) (/ 12.5073432786869052 (+ (- z 1) 5))) (/ -0.138571095265720118 (+ (- z 1) 6))) (/ 9.98436957801957158e-6 (+ (- z 1) 7))) (/ 1.50563273514931162e-7 (+ (- z 1) 8)))))

Backtrace

exact?: contract violation expected: number? given: 'h1LC
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
for-loop/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt706
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
for-loop/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt706
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
for-loop/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt706
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
for-loop/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt706
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
for-loop/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt706
egg-parsed->expr/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt650
(unnamed)/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/simplify.rkt498
egraph-add-exprs/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt1220
egraph-run/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt550
(unnamed)/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/simplify.rkt380
simplify!/data/pavpan/nightlies/herbie/eggmath-testversion/src/mainloop.rkt2230
run-improve47/data/pavpan/nightlies/herbie/eggmath-testversion/src/mainloop.rkt3450
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.2/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.2/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128