\[\frac{1.0}{\sqrt{k}} \cdot {\left(\left(2.0 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1.0 - k}{2.0}\right)}\]
\frac{1.0}{\sqrt{k}} \cdot {\left(\left(2.0 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1.0 - k}{2.0}\right)}
double f(double k, double n) {
        double r2370388 = 1.0;
        double r2370389 = k;
        double r2370390 = sqrt(r2370389);
        double r2370391 = r2370388 / r2370390;
        double r2370392 = 2.0;
        double r2370393 = atan2(1.0, 0.0);
        double r2370394 = r2370392 * r2370393;
        double r2370395 = n;
        double r2370396 = r2370394 * r2370395;
        double r2370397 = r2370388 - r2370389;
        double r2370398 = r2370397 / r2370392;
        double r2370399 = pow(r2370396, r2370398);
        double r2370400 = r2370391 * r2370399;
        return r2370400;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019165 
(FPCore (k n)
  :name "Migdal et al, Equation (51)"
  (* (/ 1.0 (sqrt k)) (pow (* (* 2.0 PI) n) (/ (- 1.0 k) 2.0))))

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
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