\HeaderA{i2xy}{Convert (x,y)-coordinates to single-number indices and back.}{i2xy}
\aliasA{xy2i}{i2xy}{xy2i}
\keyword{datasets}{i2xy}
\begin{Description}\relax
Convert (x,y)-coordinates on the chip (and in the CEL file) to the
single-number indices used in AffyBatch and CDF environment, and back.
\end{Description}
\begin{Usage}
\begin{verbatim}i2xy(i)
xy2i(x,y)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] numeric. x-coordinate (from 1 to 640)
\item[\code{y}] numeric. y-coordinate (from 1 to 640)
\item[\code{i}] numeric. single-number index (from 1 to 409600)
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
Type \code{i2xy} and \code{xy2i} at the \R{} prompt to 
view the function definitions.
\end{Details}
\begin{SeeAlso}\relax
\code{\LinkA{mgu74bcdf}{mgu74bcdf}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
  xy2i(5,5)
  i     = 1:(640*640)
  coord = i2xy(i)
  j     = xy2i(coord[, "x"], coord[, "y"])
  stopifnot(all(i==j))
  range(coord[, "x"])
  range(coord[, "y"])
\end{ExampleCode}
\end{Examples}

