\[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|\]
\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|
double f(double x, double y, double z) {
        double r8054 = x;
        double r8055 = 4.0;
        double r8056 = r8054 + r8055;
        double r8057 = y;
        double r8058 = r8056 / r8057;
        double r8059 = r8054 / r8057;
        double r8060 = z;
        double r8061 = r8059 * r8060;
        double r8062 = r8058 - r8061;
        double r8063 = fabs(r8062);
        return r8063;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 
(FPCore (x y z)
  :name "fabs fraction 1"
  (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))

Backtrace

atab-pick-alt: contract violation expected: alt? given: '(#<alt (λ (x y z) (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))>) in: the range of the #:picking-func argument of (-> alt-table? #:only-fresh boolean? #:picking-func (-> (listof alt?) alt?) (values alt? alt-table?)) contract from: /data/pavpan/nightlies/herbie/no-costs-2/src/core/alt-table.rkt blaming: /data/pavpan/nightlies/herbie/no-costs-2/src/mainloop.rkt (assuming the contract is correct) at: /data/pavpan/nightlies/herbie/no-costs-2/src/core/alt-table.rkt:13.3LC
raise-blame-error16/opt/racket-7.0/collects/racket/contract/private/blame.rkt3470
(unnamed)/data/pavpan/nightlies/herbie/no-costs-2/src/core/alt-table.rkt590
(unnamed)/opt/racket-7.0/collects/racket/contract/private/arrow-val-first.rkt38818
choose-best-alt!/data/pavpan/nightlies/herbie/no-costs-2/src/mainloop.rkt1100
run-iter!/data/pavpan/nightlies/herbie/no-costs-2/src/mainloop.rkt3190
for-loop/data/pavpan/nightlies/herbie/no-costs-2/src/mainloop.rkt3534
run-improve43/data/pavpan/nightlies/herbie/no-costs-2/src/mainloop.rkt3380
(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