Octave 3.8, jcobi/1

Specification

?
\[\alpha > -1 \land \beta > -1\]
\[\begin{array}{l} \\ \frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2} \end{array} \]
(FPCore (alpha beta)
 :precision binary64
 (/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2.0)) 1.0) 2.0))
double code(double alpha, double beta) {
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
}
real(8) function code(alpha, beta)
    real(8), intent (in) :: alpha
    real(8), intent (in) :: beta
    code = (((beta - alpha) / ((alpha + beta) + 2.0d0)) + 1.0d0) / 2.0d0
end function
public static double code(double alpha, double beta) {
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
}
def code(alpha, beta):
	return (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0
function code(alpha, beta)
	return Float64(Float64(Float64(Float64(beta - alpha) / Float64(Float64(alpha + beta) + 2.0)) + 1.0) / 2.0)
end
function tmp = code(alpha, beta)
	tmp = (((beta - alpha) / ((alpha + beta) + 2.0)) + 1.0) / 2.0;
end
code[alpha_, beta_] := N[(N[(N[(N[(beta - alpha), $MachinePrecision] / N[(N[(alpha + beta), $MachinePrecision] + 2.0), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / 2.0), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}
\end{array}

Reproduce

?
herbie shell --seed 2024039 
(FPCore (alpha beta)
  :name "Octave 3.8, jcobi/1"
  :precision binary64
  :pre (and (> alpha -1.0) (> beta -1.0))
  (/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2.0)) 1.0) 2.0))

Please file a bug report with this information.

Backtrace

member: not a proper list in: 1LC
gather-multiplicative-terms/home/nightlies/herbie/sound-rules/src/core/reduce.rkt1250
simplify-node*/home/nightlies/herbie/sound-rules/src/core/reduce.rkt840
hash-ref!/usr/local/racket/collects/racket/private/more-scheme.rkt3772
hash-ref!/usr/local/racket/collects/racket/private/more-scheme.rkt3772
loop.../private/map.rkt4019
f19.../match/compiler.rkt55940
hash-ref!/usr/local/racket/collects/racket/private/more-scheme.rkt3772
approximate/home/nightlies/herbie/sound-rules/src/core/taylor.rkt70
taylor-expr/home/nightlies/herbie/sound-rules/src/patch.rkt890
taylor-alt/home/nightlies/herbie/sound-rules/src/patch.rkt960
gen-series!/home/nightlies/herbie/sound-rules/src/patch.rkt1090
patch-table-run/home/nightlies/herbie/sound-rules/src/patch.rkt2570
(unnamed)/usr/local/racket/collects/racket/contract/private/arrow-val-first.rkt48618
run-iter!/home/nightlies/herbie/sound-rules/src/mainloop.rkt2880
mutate!/home/nightlies/herbie/sound-rules/src/mainloop.rkt3400
run-improve!/home/nightlies/herbie/sound-rules/src/mainloop.rkt3260
get-alternatives/report/home/nightlies/herbie/sound-rules/src/sandbox.rkt1690
(unnamed)/home/nightlies/herbie/sound-rules/src/sandbox.rkt2626
(unnamed)/usr/local/racket/share/pkgs/profile-lib/main.rkt4010
profile-thunk/usr/local/racket/share/pkgs/profile-lib/main.rkt90
(unnamed)/usr/local/racket/collects/racket/engine.rkt4224