\[2 \cdot \left(\left(1 \cdot \frac{1}{9} + \frac{1}{9} \cdot \frac{1}{9}\right) + \frac{1}{9} \cdot 1\right)\]
2 \cdot \left(\left(1 \cdot \frac{1}{9} + \frac{1}{9} \cdot \frac{1}{9}\right) + \frac{1}{9} \cdot 1\right)
double f() {
        double r53793 = 2.0;
        double r53794 = 1.0;
        double r53795 = 9.0;
        double r53796 = r53794 / r53795;
        double r53797 = r53794 * r53796;
        double r53798 = r53796 * r53796;
        double r53799 = r53797 + r53798;
        double r53800 = r53796 * r53794;
        double r53801 = r53799 + r53800;
        double r53802 = r53793 * r53801;
        return r53802;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019198 
(FPCore ()
  :name "Rectangular parallelepiped of dimension a×b×c"

  :herbie-target
  (+ (+ (* (* (/ 1.0 9.0) 1.0) 2.0) (* 2.0 (* (/ 1.0 9.0) (/ 1.0 9.0)))) (* 2.0 (* 1.0 (/ 1.0 9.0))))

  (* 2.0 (+ (+ (* 1.0 (/ 1.0 9.0)) (* (/ 1.0 9.0) (/ 1.0 9.0))) (* (/ 1.0 9.0) 1.0))))

Backtrace

car: contract violation expected: pair? given: '()LC
loop/data/pavpan/nightlies/herbie/master/src/points.rkt1224
prepare-points/data/pavpan/nightlies/herbie/master/src/points.rkt1460
run-improve47/data/pavpan/nightlies/herbie/master/src/mainloop.rkt3420
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.2/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.2/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128