\[\left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y\]

\left(\left(x - \frac{16}{116}\right) \cdot 3\right) \cdot y

double f(double x, double y) {
        double r8209 = x;
        double r8210 = 16.0;
        double r8211 = 116.0;
        double r8212 = r8210 / r8211;
        double r8213 = r8209 - r8212;
        double r8214 = 3.0;
        double r8215 = r8213 * r8214;
        double r8216 = y;
        double r8217 = r8215 * r8216;
        return r8217;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 
(FPCore (x y)
  :name "Data.Colour.CIE:cieLAB from colour-2.3.3, A"

  :herbie-target
  (* y (- (* x 3.0) 0.41379310344827586))

  (* (* (- x (/ 16.0 116.0)) 3.0) y))

Backtrace

get-representation: Unknown representation #f		L	C
loop	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	122	4
prepare-points	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	146	0
setup-prog!34	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	67	0
run-improve43	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	339	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