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+# Copyright (C) 1996,1998 A. Scottedward Hodel
+#
+# 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+function [n,nz,m,p,yd] = sysdimensions(sys)
+# [n,nz,m,p[,yd]] = sysdimensions(sys)
+# return the number of states, inputs, and outputs in the system sys.
+# inputs: sys: system data structure
+# outputs:
+#  n: number of continuous states
+#  nz: number of discrete states
+#  m: number of system inputs
+#  p: number of system outputs
+#  yd: is the discrete output vector: yd(ii) = 1 if output ii is sampled,
+#   				    yd(ii) = 0 if output ii is continous
+#
+# see also: sysgetsignals, sysgettsam
+
+if(nargout > 5 | nargin != 1)
+  usage("[n,nz,m,p[,yd]] = sysdimensions(sys)");
+elseif(!is_struct(sys))
+  usage("[n,nz,m,p] = sysdimensions(sys)");
+endif
+
+n = sys.n;
+nz = sys.nz;
+m = rows(sys.inname);
+p = rows(sys.outname);
+yd = sys.yd;
+
+endfunction