## Copyright (C) 1996 Auburn University.  All Rights Reserved
##
## This file is part of Octave. 
##
## Octave is free software; you can redistribute it and/or modify it 
## under the terms of the GNU General Public License as published by the 
## Free Software Foundation; either version 2, or (at your option) any 
## later version. 
## 
## Octave is distributed in the hope that it will be useful, but WITHOUT 
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
## FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License 
## for more details.
## 
## You should have received a copy of the GNU General Public License 
## along with Octave; see the file COPYING.  If not, write to the Free 
## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. 
 
##  function [systype, nout, nin, ncstates, ndstates] = minfo(inmat)
##
## MINFO:  Determines the type of system matrix.  INMAT can be
##         a varying(*), system, constant, and empty matrix.
##
##    Returns:
##      systype can be one of:
##            varying, system, constant, and empty
##      nout is the number of outputs of the system
##      nin is the number of inputs of the system
##      ncstates is the number of continuous states of the system
##	 ndstates is the number of discrete states of the system

function [systype, nout, nin, ncstates, ndstates] = minfo (inmat)

  ## Written by R. Bruce Tenison July 29, 1994
  ## Modified by David Clem November 13, 1994
  ## Modified by A. S. Hodel July 1995

  warning("minfo: obsolete.  Use sys2ss, sys2tf, or sys2zp.");
    
  if (nargin ~= 1 )
    disp('MINFO: Wrong number of arguments')
    systype = nout = nin = ncstates = ndstates = [];
  endif
  
  [rr,cc] = size(inmat);
  
  ## Check for empty matrix first!
  if (isempty(inmat))
    systype = "empty";
    nout = nin = ncstates = ndstates = 0;
    return
  
  ## Check for Constant matrix

  elseif (rr == 1 || cc == 1)
    systype = "constant";
    nout = nin = ncstates = ndstates = 1;
    return
  
  ## Check for system type matrix
  elseif (inmat(rr,cc) == -Inf)
    systype = "system";
    ncstates = inmat(1,cc);
    ndstates = inmat(rr,1);
    nstates = ncstates + ndstates;
    nout = rr - nstates - 1;
    nin = cc - nstates - 1;
  
  ## Check for Varying type matrix
  elseif (inmat(rr,cc) == Inf)
    systype = "varying";
    npoints = inmat(rr,cc-1);
    nin = cc - 1;
    nout = rr / npoints;
    nstates = 0;

    ## Must be a standard matrix
  else
    systype = "constant";
    nin = cc;
    nout = rr;
    ncstates = 0;
    ndstates = 0;
  endif
endfunction
