\HeaderA{trigammaInverse}{Inverse Trigamma Function}{trigammaInverse}
\keyword{math}{trigammaInverse}
\begin{Description}\relax
The inverse of the trigamma function.
\end{Description}
\begin{Usage}
\begin{verbatim}
trigammaInverse(x)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] numeric vector or array
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
The function uses Newton's method with a clever starting value to ensure monotonic convergence.
\end{Details}
\begin{Value}
Numeric vector or array \code{y} satisfying \code{trigamma(y)==x}.
\end{Value}
\begin{Note}\relax
This function does not accept a data.frame as argument although the internal function \code{trigamma} does.
\end{Note}
\begin{Author}\relax
Gordon Smyth
\end{Author}
\begin{SeeAlso}\relax
\code{\LinkA{trigamma}{trigamma}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
y <- trigammaInverse(5)
trigamma(y)
\end{ExampleCode}
\end{Examples}