\[\frac{x + \frac{y \cdot z}{t}}{\left(a + 1\right) + \frac{y \cdot b}{t}} \]
(FPCore (x y z t a b)
 :precision binary64
 (/ (+ x (/ (* y z) t)) (+ (+ a 1.0) (/ (* y b) t))))
double code(double x, double y, double z, double t, double a, double b) {
	return (x + ((y * z) / t)) / ((a + 1.0) + ((y * b) / t));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (x + ((y * z) / t)) / ((a + 1.0d0) + ((y * b) / t))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return (x + ((y * z) / t)) / ((a + 1.0) + ((y * b) / t));
}
def code(x, y, z, t, a, b):
	return (x + ((y * z) / t)) / ((a + 1.0) + ((y * b) / t))
function code(x, y, z, t, a, b)
	return Float64(Float64(x + Float64(Float64(y * z) / t)) / Float64(Float64(a + 1.0) + Float64(Float64(y * b) / t)))
end
function tmp = code(x, y, z, t, a, b)
	tmp = (x + ((y * z) / t)) / ((a + 1.0) + ((y * b) / t));
end
code[x_, y_, z_, t_, a_, b_] := N[(N[(x + N[(N[(y * z), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision] / N[(N[(a + 1.0), $MachinePrecision] + N[(N[(y * b), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\frac{x + \frac{y \cdot z}{t}}{\left(a + 1\right) + \frac{y \cdot b}{t}}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2022204 
(FPCore (x y z t a b)
  :name "Diagrams.Solve.Tridiagonal:solveCyclicTriDiagonal from diagrams-solve-0.1, B"
  :precision binary64

  :herbie-target
  (if (< t -1.3659085366310088e-271) (* 1.0 (* (+ x (* (/ y t) z)) (/ 1.0 (+ (+ a 1.0) (* (/ y t) b))))) (if (< t 3.036967103737246e-130) (/ z b) (* 1.0 (* (+ x (* (/ y t) z)) (/ 1.0 (+ (+ a 1.0) (* (/ y t) b)))))))

  (/ (+ x (/ (* y z) t)) (+ (+ a 1.0) (/ (* y b) t))))

Backtrace

nan?: contract violation expected: real? given: 0.5000000000000001+0.8660254037844386iLC
simplify-node*/data/pavpan/nightlies/herbie/fix-inf-exact/src/core/reduce.rkt610
hash-ref!/usr/share/racket/collects/racket/private/more-scheme.rkt3772
hash-ref!/usr/share/racket/collects/racket/private/more-scheme.rkt3772
approximate/data/pavpan/nightlies/herbie/fix-inf-exact/src/core/taylor.rkt70
taylor-expr/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt780
taylor-alt/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt850
gen-series!/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt1010
patch-table-run/data/pavpan/nightlies/herbie/fix-inf-exact/src/patch.rkt3100
(unnamed)/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt48618
run-iter!/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt2420
mutate!/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt3480
run-improve!/data/pavpan/nightlies/herbie/fix-inf-exact/src/mainloop.rkt2960
(unnamed)/data/pavpan/nightlies/herbie/fix-inf-exact/src/sandbox.rkt556
(unnamed)/usr/share/racket/pkgs/profile-lib/main.rkt4010
profile-thunk/usr/share/racket/pkgs/profile-lib/main.rkt90
(unnamed)/usr/share/racket/collects/racket/engine.rkt4224