\name{asFactorMatrix}
\alias{asFactorMatrix}
\title{Make factor matrix from character matrix}
\usage{
  asFactorMatrix(object, levels)
}
\arguments{
  \item{object}{matrix of characters}

  \item{levels}{character}
}
\value{
  factor with dimensions matching object
}
\description{
  Make factor matrix from character matrix for use with
  convertToBigMatrix. Makes an integer matrix with levels
  since as.big.matrix would make a factor matrix into a 1D
  object for some reason. Character matrices should be
  converted to factors with explicit levels as huge
  matrices are likely too big to unique.
}
\details{
  Caution: use asFactorMatrix on matrices already in an
  eSet.  The eSet constructor will apparently wipe out the
  levels.
}
\author{
  Peter M. Haverty \email{phaverty@gene.com}
}