The Inverse Hyperbolic Tangent Function: atanh

Syntax
y = atanh(x)

Description
The inverse hyperbolic tangent function is defined by x == tanh(y) .

x, y
See the possible types for a unary standard math function.

If this preprocessor symbol is true (1), and x is an AD type, this is an atomic operation .
If this preprocessor symbol is false (0), CppAD uses the representation $$\R{atanh} (x) = \frac{1}{2} \log \left( \frac{1 + x}{1 - x} \right)$$ to compute this function.