\[\frac{1}{3} \cdot \cos^{-1} \left(\frac{3 \cdot \frac{x}{y \cdot 27}}{z \cdot 2} \cdot \sqrt{t}\right)\]

\frac{1}{3} \cdot \cos^{-1} \left(\frac{3 \cdot \frac{x}{y \cdot 27}}{z \cdot 2} \cdot \sqrt{t}\right)

double code(double x, double y, double z, double t) {
	return ((double) (((double) (1.0 / 3.0)) * ((double) acos(((double) (((double) (((double) (3.0 * ((double) (x / ((double) (y * 27.0)))))) / ((double) (z * 2.0)))) * ((double) sqrt(t))))))));
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020165 
(FPCore (x y z t)
  :name "Diagrams.Solve.Polynomial:cubForm  from diagrams-solve-0.1, D"
  :precision binary64

  :herbie-target
  (/ (acos (* (/ (/ x 27.0) (* y z)) (/ (sqrt t) (/ 2.0 3.0)))) 3.0)

  (* (/ 1.0 3.0) (acos (* (/ (* 3.0 (/ x (* y 27.0))) (* z 2.0)) (sqrt t)))))

Backtrace

ival-hi: contract violation expected: ival? given: #<procedure:interval>		L	C
for-loop	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	37	11
hyperrect-weight	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	36	0
total-weight	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	113	2
log-space-improvement	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	110	0
(unnamed)	/opt/racket-7.5/collects/racket/contract/private/arrow-higher-order.rkt	375	33
get-hyperrects	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	123	0
make-sampler	/data/pavpan/nightlies/herbie/ival-find-range/src/sampling.rkt	147	0
prepare-points-intervals	/data/pavpan/nightlies/herbie/ival-find-range/src/points.rkt	90	0
run-improve47	/data/pavpan/nightlies/herbie/ival-find-range/src/mainloop.rkt	365	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 2020165 
(FPCore (x y z t)
  :name "Diagrams.Solve.Polynomial:cubForm  from diagrams-solve-0.1, D"
  :precision binary64

  :herbie-target
  (/ (acos (* (/ (/ x 27.0) (* y z)) (/ (sqrt t) (/ 2.0 3.0)))) 3.0)

  (* (/ 1.0 3.0) (acos (* (/ (* 3.0 (/ x (* y 27.0))) (* z 2.0)) (sqrt t)))))