\[0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\]
0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}
double f(double re, double im) {
        double r8021 = 0.5;
        double r8022 = 2.0;
        double r8023 = re;
        double r8024 = r8023 * r8023;
        double r8025 = im;
        double r8026 = r8025 * r8025;
        double r8027 = r8024 + r8026;
        double r8028 = sqrt(r8027);
        double r8029 = r8028 - r8023;
        double r8030 = r8022 * r8029;
        double r8031 = sqrt(r8030);
        double r8032 = r8021 * r8031;
        return r8032;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 
(FPCore (re im)
  :name "math.sqrt on complex, imaginary part, im greater than 0 branch"
  (* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))

Backtrace

atab-pick-alt: contract violation expected: alt? given: '(#<alt (λ (re im) (* 0.5 (sqrt (* 2.0 (- (sqrt (+ (* re re) (* im im))) re)))))>) 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