\[\sqrt{\left(\left(2 \cdot n\right) \cdot U\right) \cdot \left(\left(t - 2 \cdot \frac{\ell \cdot \ell}{Om}\right) - \left(n \cdot {\left(\frac{\ell}{Om}\right)}^{2}\right) \cdot \left(U - U*\right)\right)}\]

\sqrt{\left(\left(2 \cdot n\right) \cdot U\right) \cdot \left(\left(t - 2 \cdot \frac{\ell \cdot \ell}{Om}\right) - \left(n \cdot {\left(\frac{\ell}{Om}\right)}^{2}\right) \cdot \left(U - U*\right)\right)}

double f(double n, double U, double t, double l, double Om, double U_) {
        double r209288 = 2.0;
        double r209289 = n;
        double r209290 = r209288 * r209289;
        double r209291 = U;
        double r209292 = r209290 * r209291;
        double r209293 = t;
        double r209294 = l;
        double r209295 = r209294 * r209294;
        double r209296 = Om;
        double r209297 = r209295 / r209296;
        double r209298 = r209288 * r209297;
        double r209299 = r209293 - r209298;
        double r209300 = r209294 / r209296;
        double r209301 = pow(r209300, r209288);
        double r209302 = r209289 * r209301;
        double r209303 = U_;
        double r209304 = r209291 - r209303;
        double r209305 = r209302 * r209304;
        double r209306 = r209299 - r209305;
        double r209307 = r209292 * r209306;
        double r209308 = sqrt(r209307);
        return r209308;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019323 
(FPCore (n U t l Om U*)
  :name "Toniolo and Linder, Equation (13)"
  :precision binary64
  (sqrt (* (* (* 2 n) U) (- (- t (* 2 (/ (* l l) Om))) (* (* n (pow (/ l Om) 2)) (- U U*))))))

Backtrace

dict-ref: no value for key: 'branch209287 in: '((n . binary64) (U . binary64) (t . binary64) (l . binary64) (Om . binary64) (U* . binary64))		L	C
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt	106	4
make-sampler	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt	99	0
prepare-points-intervals	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt	121	0
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	233	9
sindices->spoints	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	194	0
f33	/opt/racket-7.2/collects/racket/match/compiler.rkt	507	40
get-final-combination	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	369	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28