Exception for quadm (p42, negative)

Math

\[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020128 
(FPCore (a b c)
  :name "quadm (p42, negative)"
  :precision binary64

  :herbie-target
  (if (< b 0.0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))

  (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))

Backtrace

random-bits: contract violation expected: Positive-Integer given: 0		L	C
random-ranges	/data/pavpan/nightlies/herbie/separate-biginterval/src/common.rkt	139	0
sample-multi-bounded	/data/pavpan/nightlies/herbie/separate-biginterval/src/points.rkt	14	0
(unnamed)	/data/pavpan/nightlies/herbie/separate-biginterval/src/points.rkt	127	6
prepare-points-intervals	/data/pavpan/nightlies/herbie/separate-biginterval/src/points.rkt	134	0
pred	/data/pavpan/nightlies/herbie/separate-biginterval/src/core/regimes.rkt	200	4
for-loop	/data/pavpan/nightlies/herbie/separate-biginterval/src/core/regimes.rkt	230	9
sindices->spoints	/data/pavpan/nightlies/herbie/separate-biginterval/src/core/regimes.rkt	190	0
f37	unknown
get-final-combination	/data/pavpan/nightlies/herbie/separate-biginterval/src/mainloop.rkt	390	0
.../more-scheme.rkt:261:28	unknown
run	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.5/collects/racket/private/more-scheme.rkt	261	28

Reproduce

herbie shell --seed 2020128 
(FPCore (a b c)
  :name "quadm (p42, negative)"
  :precision binary64

  :herbie-target
  (if (< b 0.0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))

  (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))