\name{norm}
\alias{norm}
\title{
    Norm of a Matrix
}
\usage{norm(x, type, \dots) }
\description{
    Computes a matrix norm of \code{x} using Lapack.  The norm can be
    the one norm, the infinity norm, the Frobenius norm, or the maximum
    modulus among elements of a matrix, as determined by the value of
    \code{type}.
}
\arguments{
  \item{x}{
    a real or complex matrix.
  }
  \item{type}{
    A character indicating the type of norm desired.
    \code{"O"} or \code{"o"} or \code{"1"} specifies the one norm,
    (maximum absolute column sum);
    \code{"I"} or \code{"i"} specifies the infinity norm (maximum
    absolute row sum);
    \code{"F"} or \code{"f"} specifies the Frobenius norm (the
    Euclidean norm of \code{x} treated as if it were a vector);
    and \code{"M"} or \code{"m"} specifies the maximum modulus of
    all the elements in \code{x}. The default is \code{"O"}.
    
    Only the first character of \code{type[1]} is used.
  }
  \item{\dots}{further arguments passed to or from other methods.}
}
\value{
    A numeric value of class \code{"norm"}, representing the quantity
    chosen according to \code{type}.
}
\details{
    Based on the Lapack functions \code{dlange}, \code{dlansy}, \code{dlantr},
    \code{zlange},  \code{zlansy}, and \code{zlantr}.
}
\references{
    Anderson, E., et al. (1994).
    \emph{LAPACK User's Guide,}
    2nd edition, SIAM, Philadelphia.
}
\examples{
x <- Hilbert(9)
norm(x, "1")
norm(x, "I")
norm(x, "F")
norm(x, "M")
}
\keyword{algebra}