\[\log \left(x + \sqrt{x \cdot x - 1}\right)\]
\log \left(x + \sqrt{x \cdot x - 1}\right)
double f(double x) {
        double r8111 = x;
        double r8112 = r8111 * r8111;
        double r8113 = 1.0;
        double r8114 = r8112 - r8113;
        double r8115 = sqrt(r8114);
        double r8116 = r8111 + r8115;
        double r8117 = log(r8116);
        return r8117;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 
(FPCore (x)
  :name "Hyperbolic arc-cosine"
  (log (+ x (sqrt (- (* x x) 1.0)))))

Backtrace

atab-pick-alt: contract violation expected: alt? given: '(#<alt (λ (x) (log (+ x (sqrt (- (* x x) 1.0)))))>) 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