Specification

\[\left|x\right| \leq 1\]

\[\begin{array}{l} \\ \frac{\log \left(1 - x\right)}{\log \left(1 + x\right)} \end{array} \]

(FPCore (x) :precision binary64 (/ (log (- 1.0 x)) (log (+ 1.0 x))))

double code(double x) {
	return log((1.0 - x)) / log((1.0 + x));
}

real(8) function code(x)
    real(8), intent (in) :: x
    code = log((1.0d0 - x)) / log((1.0d0 + x))
end function

public static double code(double x) {
	return Math.log((1.0 - x)) / Math.log((1.0 + x));
}

def code(x):
	return math.log((1.0 - x)) / math.log((1.0 + x))

function code(x)
	return Float64(log(Float64(1.0 - x)) / log(Float64(1.0 + x)))
end

function tmp = code(x)
	tmp = log((1.0 - x)) / log((1.0 + x));
end

code[x_] := N[(N[Log[N[(1.0 - x), $MachinePrecision]], $MachinePrecision] / N[Log[N[(1.0 + x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]

\begin{array}{l}

\\
\frac{\log \left(1 - x\right)}{\log \left(1 + x\right)}
\end{array}

Reproduce

herbie shell --seed 2024005 
(FPCore (x)
  :name "qlog (example 3.10)"
  :precision binary64
  :pre (<= (fabs x) 1.0)

  :herbie-target
  (/ (log1p (- x)) (log1p x))

  (/ (log (- 1.0 x)) (log (+ 1.0 x))))

Please file a bug report with this information.

Backtrace

repr->cost: arity mismatch; the expected number of arguments does not match the given number expected: 2 given: 1		L	C
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
make-alt-table	/home/nightlies/herbie/platforms/src/core/alt-table.rkt	40	0
(unnamed)	/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt	486	18
initialize-alt-table!	/home/nightlies/herbie/platforms/src/mainloop.rkt	316	0
mutate!	/home/nightlies/herbie/platforms/src/mainloop.rkt	352	0
run-improve!	/home/nightlies/herbie/platforms/src/mainloop.rkt	338	0
get-alternatives/report	/home/nightlies/herbie/platforms/src/sandbox.rkt	169	0
(unnamed)	/home/nightlies/herbie/platforms/src/sandbox.rkt	262	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24