\[\frac{\sqrt{2} \cdot t}{\sqrt{\frac{x + 1}{x - 1} \cdot \left(\ell \cdot \ell + 2 \cdot \left(t \cdot t\right)\right) - \ell \cdot \ell}}\]

\frac{\sqrt{2} \cdot t}{\sqrt{\frac{x + 1}{x - 1} \cdot \left(\ell \cdot \ell + 2 \cdot \left(t \cdot t\right)\right) - \ell \cdot \ell}}

double f(double x, double l, double t) {
        double r7982 = 2.0;
        double r7983 = sqrt(r7982);
        double r7984 = t;
        double r7985 = r7983 * r7984;
        double r7986 = x;
        double r7987 = 1.0;
        double r7988 = r7986 + r7987;
        double r7989 = r7986 - r7987;
        double r7990 = r7988 / r7989;
        double r7991 = l;
        double r7992 = r7991 * r7991;
        double r7993 = r7984 * r7984;
        double r7994 = r7982 * r7993;
        double r7995 = r7992 + r7994;
        double r7996 = r7990 * r7995;
        double r7997 = r7996 - r7992;
        double r7998 = sqrt(r7997);
        double r7999 = r7985 / r7998;
        return r7999;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x l t)
  :name "Toniolo and Linder, Equation (7)"
  (/ (* (sqrt 2.0) t) (sqrt (- (* (/ (+ x 1.0) (- x 1.0)) (+ (* l l) (* 2.0 (* t t)))) (* l l)))))

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