\[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]

\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}

double f(double v, double t) {
        double r128204 = 1.0;
        double r128205 = 5.0;
        double r128206 = v;
        double r128207 = r128206 * r128206;
        double r128208 = r128205 * r128207;
        double r128209 = r128204 - r128208;
        double r128210 = atan2(1.0, 0.0);
        double r128211 = t;
        double r128212 = r128210 * r128211;
        double r128213 = 2.0;
        double r128214 = 3.0;
        double r128215 = r128214 * r128207;
        double r128216 = r128204 - r128215;
        double r128217 = r128213 * r128216;
        double r128218 = sqrt(r128217);
        double r128219 = r128212 * r128218;
        double r128220 = r128204 - r128207;
        double r128221 = r128219 * r128220;
        double r128222 = r128209 / r128221;
        return r128222;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019196 
(FPCore (v t)
  :name "Falkner and Boettcher, Equation (20:1,3)"
  (/ (- 1.0 (* 5.0 (* v v))) (* (* (* PI t) (sqrt (* 2.0 (- 1.0 (* 3.0 (* v v)))))) (- 1.0 (* v v)))))

Backtrace

get-representation: Unknown representation #f		L	C
(unnamed)	/data/pavpan/nightlies/herbie/master/src/core/localize.rkt	23	13
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
map	/opt/racket-7.0/collects/racket/private/map.rkt	35	13
parse-loop30	/opt/racket-7.0/collects/racket/match/compiler.rkt	418	15
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
map	/opt/racket-7.0/collects/racket/private/map.rkt	35	13
parse-loop30	/opt/racket-7.0/collects/racket/match/compiler.rkt	418	15
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
map	/opt/racket-7.0/collects/racket/private/map.rkt	35	13
parse-loop30	/opt/racket-7.0/collects/racket/match/compiler.rkt	418	15
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
localize-error	/data/pavpan/nightlies/herbie/master/src/core/localize.rkt	61	0
localize!	/data/pavpan/nightlies/herbie/master/src/mainloop.rkt	123	0
run-iter!	/data/pavpan/nightlies/herbie/master/src/mainloop.rkt	323	0
for-loop	/data/pavpan/nightlies/herbie/master/src/mainloop.rkt	359	4
run-improve47	/data/pavpan/nightlies/herbie/master/src/mainloop.rkt	342	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