--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@ssm/sMinReal.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,108 @@
+% SMINREAL gives a minimal realization of a ssm object by deleting unreached states
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: SMINREAL gives a minimal realization of a ssm object by
+%              deleting unreached states (! this is not always the minimal realization)
+%
+% CALL:        >> sys = sMinReal(sys);
+%
+%            sys - an array of ssm object
+%
+% <a href="matlab:utils.helper.displayMethodInfo('ssm', 'sMinReal')">Parameters Description</a>
+%
+% VERSION: $Id: sMinReal.m,v 1.14 2011/04/08 08:56:23 hewitson Exp $
+% 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function varargout = sMinReal(varargin)
+  
+  %% Check if this is a call for parameters
+  if utils.helper.isinfocall(varargin{:})
+    varargout{1} = getInfo(varargin{3});
+    return
+  end
+  
+  %% send starting message
+  import utils.const.*
+  utils.helper.msg(msg.PROC3, 'running %s/%s', mfilename('class'), mfilename);
+  
+  %% collecting input
+  in_names = cell(size(varargin));
+  for ii = 1:nargin,in_names{ii} = inputname(ii);end
+  
+  [sys, ssm_invars] = utils.helper.collect_objects(varargin(:), 'ssm', in_names);
+  
+  pl_user = plist;
+  
+  internal = strcmp(varargin{end}, 'internal');
+  
+  sys = copy(sys, nargout);
+  
+  %% begin function body
+  for i_sys=1:numel(sys)
+    if ~sys(i_sys).isnumerical
+      error('system should be numeric')
+    end
+    [A, B, C] = double(sys(i_sys), plist);
+    x_control = isreached(A,B);
+    x_sensing = isreached(A.',C.');
+    x = logical(min(x_control, x_sensing));
+    positions = ssm.blockMatRecut(x,sys(i_sys).sssizes, 1);
+    
+    options = plist('inputs','ALL','outputs','ALL', 'states', positions);
+    sys(i_sys).doSimplify(options);
+    if ~internal
+      % append history step
+      sys(i_sys).addHistory(getInfo('None'), pl_user, ssm_invars(i_sys), sys(i_sys).hist);
+    end
+  end
+  if nargout == numel(sys)
+    for ii = 1:numel(sys)
+      varargout{ii} = sys(ii);
+    end
+  else
+    varargout{1} = sys;
+  end
+  
+end
+
+function x  = isreached(A,B)
+  Alog = double(~(A==0));
+  Blog = double(~(B==0));
+  Nss = size(B,1);
+  Nin = size(B,2);
+  x = zeros(Nss, 1);
+  for i =0:Nss
+    Ai = Alog^i;
+    for j=1:Nin
+      xloc = Ai*Blog(:,j);
+      xloc = double(~(xloc==0));
+      x = max(x, xloc);
+    end
+  end
+end
+
+
+%--------------------------------------------------------------------------
+% Get Info Object
+%--------------------------------------------------------------------------
+function ii = getInfo(varargin)
+  
+  if nargin == 1 && strcmpi(varargin{1}, 'None')
+    sets = {};
+    pl   = [];
+  else
+    sets = {'Default'};
+    pl   = getDefaultPlist;
+  end
+  % Build info object
+  ii = minfo(mfilename, 'ssm', 'ltpda', utils.const.categories.op, '$Id: sMinReal.m,v 1.14 2011/04/08 08:56:23 hewitson Exp $', sets, pl);
+end
+
+%--------------------------------------------------------------------------
+% Get Default Plist
+%--------------------------------------------------------------------------
+function plo = getDefaultPlist()
+  plo = plist;
+end
+