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

(FPCore (x) :precision binary64 (- (log1p (- x)) (log1p x)))

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

double code(double x) {
	return log1p(-x) - log1p(x);
}

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

public static double code(double x) {
	return Math.log1p(-x) - Math.log1p(x);
}

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

def code(x):
	return math.log1p(-x) - math.log1p(x)

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

function code(x)
	return Float64(log1p(Float64(-x)) - log1p(x))
end

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

code[x_] := N[(N[Log[1 + (-x)], $MachinePrecision] - N[Log[1 + x], $MachinePrecision]), $MachinePrecision]

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

\mathsf{log1p}\left(-x\right) - \mathsf{log1p}\left(x\right)