\[\left|\frac{1}{\sqrt{\pi}} \cdot \left(\left(\left(2 \cdot \left|x\right| + \frac{2}{3} \cdot \left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{5} \cdot \left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{21} \cdot \left(\left(\left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right)\right|\]
\left|\frac{1}{\sqrt{\pi}} \cdot \left(\left(\left(2 \cdot \left|x\right| + \frac{2}{3} \cdot \left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{5} \cdot \left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{21} \cdot \left(\left(\left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right)\right|
double f(double x) {
        double r115766 = 1.0;
        double r115767 = atan2(1.0, 0.0);
        double r115768 = sqrt(r115767);
        double r115769 = r115766 / r115768;
        double r115770 = 2.0;
        double r115771 = x;
        double r115772 = fabs(r115771);
        double r115773 = r115770 * r115772;
        double r115774 = 3.0;
        double r115775 = r115770 / r115774;
        double r115776 = r115772 * r115772;
        double r115777 = r115776 * r115772;
        double r115778 = r115775 * r115777;
        double r115779 = r115773 + r115778;
        double r115780 = 5.0;
        double r115781 = r115766 / r115780;
        double r115782 = r115777 * r115772;
        double r115783 = r115782 * r115772;
        double r115784 = r115781 * r115783;
        double r115785 = r115779 + r115784;
        double r115786 = 21.0;
        double r115787 = r115766 / r115786;
        double r115788 = r115783 * r115772;
        double r115789 = r115788 * r115772;
        double r115790 = r115787 * r115789;
        double r115791 = r115785 + r115790;
        double r115792 = r115769 * r115791;
        double r115793 = fabs(r115792);
        return r115793;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019195 +o rules:numerics
(FPCore (x)
  :name "Jmat.Real.erfi, branch x less than or equal to 0.5"
  (fabs (* (/ 1.0 (sqrt PI)) (+ (+ (+ (* 2.0 (fabs x)) (* (/ 2.0 3.0) (* (* (fabs x) (fabs x)) (fabs x)))) (* (/ 1.0 5.0) (* (* (* (* (fabs x) (fabs x)) (fabs x)) (fabs x)) (fabs x)))) (* (/ 1.0 21.0) (* (* (* (* (* (* (fabs x) (fabs x)) (fabs x)) (fabs x)) (fabs x)) (fabs x)) (fabs x)))))))

Backtrace

get-representation: Unknown representation #fLC
(unnamed)/data/pavpan/nightlies/herbie/various-cleanup/src/core/localize.rkt2313
hash-ref!/opt/racket-7.0/collects/racket/private/more-scheme.rkt3762
map/opt/racket-7.0/collects/racket/private/map.rkt3513
parse-loop30/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
parse-loop30/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
parse-loop30/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
parse-loop30/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/various-cleanup/src/core/localize.rkt610
localize!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt1230
run-iter!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3230
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3594
run-improve47/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3420
(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