\name{samplesPerFeature}
\alias{samplesPerFeature}
\title{Factor Analysis for Bicluster Acquisition: Supplies samples per feature}
\description{

  \code{samplesPerFeature}: C implementation of  \code{samplesPerFeature}.
}
\usage{

samplesPerFeature(X,samples=0,lowerB=0.0,upperB=1000.0)

}
\arguments{
  \item{X}{the file name of the sparse matrix in sparse format.}
  \item{samples}{vector of samples which should be read; default
    = 0 (all samples)} 
  \item{lowerB}{lower bound for filtering the inputs columns, the
    minimal column sum; default = 0.0.} 
  \item{upperB}{upper bound for filtering the inputs columns, the
    maximal column sum; default = 1000.0.} 
}
\details{

  Supplies the samples for which a feature is not zero.

  The data matrix is
  directly scanned by the C-code and must be in sparse matrix format.

  Sparse matrix format:
  *first line: numer of rows (the samples).
  *second line: number of columns (the features).
  *following lines: for each sample (rows) three lines with

  I) number of nonzero row elements

  II) indices of the nonzero row elements (ATTENTION: starts with 0!!)

  III) values of the nonzero row elements (ATTENTION: floats with
  decimal point like 1.0 !!)


  The code is implemented in C.

}
\value{
  \item{}{list with elements:
  \code{sL} (List with one element per feature: each element is a vector
  of samples where the feature is not zero.)
  \code{nsL} {Vector of feature length containing number of samples
    having a non-zero feature value.}
}
}
\seealso{
\code{\link{fabia}},
\code{\link{fabias}},
\code{\link{fabiap}},
\code{\link{spfabia}},
\code{\link{readSamplesSpfabia}},
\code{\link{samplesPerFeature}},
\code{\link{readSpfabiaResult}},
\code{\link{fabi}},
\code{\link{fabiasp}},
\code{\link{mfsc}},
\code{\link{nmfdiv}},
\code{\link{nmfeu}},
\code{\link{nmfsc}},
\code{\link{plot}},
\code{\link{extractPlot}},
\code{\link{extractBic}},
\code{\link{plotBicluster}},
\code{\link{Factorization}},
\code{\link{projFuncPos}},
\code{\link{projFunc}},
\code{\link{estimateMode}},
\code{\link{makeFabiaData}},
\code{\link{makeFabiaDataBlocks}},
\code{\link{makeFabiaDataPos}},
\code{\link{makeFabiaDataBlocksPos}},
\code{\link{matrixImagePlot}},
\code{\link{summary}},
\code{\link{show}},
\code{\link{showSelected}},
\code{\link{fabiaDemo}},
\code{\link{fabiaVersion}}
}
\author{Sepp Hochreiter}
\examples{

#---------------
# TEST
#---------------



}


\references{
  S. Hochreiter et al.,
  \sQuote{FABIA: Factor Analysis for Bicluster Acquisition},
  Bioinformatics 26(12):1520-1527, 2010.
  http://bioinformatics.oxfordjournals.org/cgi/content/abstract/btq227
  

}
\keyword{methods}
\keyword{multivariate}
\keyword{cluster}
\concept{biclustering}
\concept{factor analysis}
\concept{sparse coding}
\concept{Laplace distribution}
\concept{EM algorithm}
\concept{non-negative matrix factorization}
\concept{multivariate analysis}
\concept{latent variables}