\[x \cdot x - \left(y \cdot 4\right) \cdot \left(z \cdot z - t\right)\]
x \cdot x - \left(y \cdot 4\right) \cdot \left(z \cdot z - t\right)
double f(double x, double y, double z, double t) {
        double r9540 = x;
        double r9541 = r9540 * r9540;
        double r9542 = y;
        double r9543 = 4.0;
        double r9544 = r9542 * r9543;
        double r9545 = z;
        double r9546 = r9545 * r9545;
        double r9547 = t;
        double r9548 = r9546 - r9547;
        double r9549 = r9544 * r9548;
        double r9550 = r9541 - r9549;
        return r9550;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x y z t)
  :name "Graphics.Rasterific.Shading:$sradialGradientWithFocusShader from Rasterific-0.6.1, B"

  :herbie-target
  (- (* x x) (* 4.0 (* y (- (* z z) t))))

  (- (* x x) (* (* y 4.0) (- (* z z) t))))

Backtrace

get-representation: Unknown representation #fLC
loop/data/pavpan/nightlies/herbie/interface2/src/points.rkt1224
prepare-points/data/pavpan/nightlies/herbie/interface2/src/points.rkt1460
setup-prog!34/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt670
run-improve43/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt3390
(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