public RData DM_RDTR(int irow, int icol, String partName)
          throws IOException {
    return DM_RDTR(irow, icol, partName, 1);
  }
public RData DM_RDTR(int irow, int icol, String partName)
          throws IOException {
    return DM_RDTR(irow, icol, partName, 1);
  }
public RData DM_RDTR ( int irow , int icol , String partName ) throws IOException { return DM_RDTR ( irow , icol , partName , 1 ) ; }
Read the data

@param irow     row to read
@param icol     column to read
@param partName part name
@return the header and data array  or null;
@throws IOException problem reading file
Read the data