\title{Methods for eSet derivatives}

  \code{chromosome} return the chromosome number for SNP and NP probes.
  \code{cnIndex, ...} return the row indices of copy number probes.

  \code{position} return the physical position of the SNP or the
  physical position for the first index of the NP probe.
  \code{snpIndex, ...} return the row indices of polymorphic loci.



  cnIndex(object, ...)
  snpIndex(object, ...)


  \item{object}{Any object extending eSet (ABset, CopyNumberSet,
    CrlmmSetList, SnpSet}

  \item{\dots}{Usually the character string indicating annotation package.}



  Vector of indices.