--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@ssm/ssm2pzmodel.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,176 @@
+% SSM2PZMODEL converts a time-continuous statespace model object to a pzmodel
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: SSM2PZMODEL converts a time-continuous statespace model
+%              object to a pzmodel
+%
+% CALL:
+%              >> pzms = ssm2pzmodel(ssm, pl);
+%
+% INPUT :
+%
+%           ssm     - a ssm object
+%           pl      - a plist with parameters 'inputs', 'states' and
+%                     'outputs' to indicate which inputs, states and output
+%                     variables are taken in account. This requires proper
+%                     variable naming. If a variable called appears more
+%                     that once it will be used once only.
+%
+% OUTPUT:
+%
+%            pzms - an array of pzmodels objects if the timestep is zero
+%
+% <a href="matlab:utils.helper.displayMethodInfo('ssm', 'ssm2pzmodel')">Parameters Description</a>
+%
+% VERSION: $Id: ssm2pzmodel.m,v 1.21 2011/04/08 08:56:23 hewitson Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function varargout = ssm2pzmodel(varargin)
+  
+  % Check if this is a call for parameters
+  if utils.helper.isinfocall(varargin{:})
+    varargout{1} = getInfo(varargin{3});
+    return
+  end
+  
+  %% starting initial checks
+  utils.helper.msg(utils.const.msg.MNAME, ['running ', mfilename]);
+  
+  % Collect input variable names
+  in_names = cell(size(varargin));
+  for ii = 1:nargin,in_names{ii} = inputname(ii);end
+  
+  % Collect all SSMs and plists
+  [sys, ssm_invars, rest] = utils.helper.collect_objects(varargin(:), 'ssm', in_names);
+  [pl, invars2, rest]  = utils.helper.collect_objects(rest(:), 'plist');
+  if ~isempty(rest)
+    pl = combine(pl, plist(rest{:}));
+  end
+  pl = combine(pl, getDefaultPlist);
+  
+  if numel(sys) ~= 1
+    error('### Input (only) one SSM object.');
+  end
+  
+  %% begin function body
+  
+  %% convert to double
+  % Convert to double arrays
+  [A,B,C,D,Ts,inputvarnames,ssvarnames,outputvarnames, inputunit, ssunit, outputunit] =...
+    double(sys, pl);
+  
+  Ninputs_out  = numel(inputvarnames);
+  Noutputs_out = numel(outputvarnames);
+  
+  if Ts > 0
+    error('ssm should be time continuous, use ssm2miir instead')
+  end
+  %% convert to pzm
+  pzm_out = pzmodel.initObjectWithSize(Noutputs_out, Ninputs_out);
+  for ii=1:Ninputs_out
+    for oo=1:Noutputs_out
+      [b,a] = ss2tf(A,B(:,ii),C(oo,:),D(oo, ii));
+      % computing poles and zeros
+      pa = roots(a);
+      if isempty(pa)
+        p = pz.initObjectWithSize(1,0);
+        gainP = 1;
+      else
+        [p, gainP] = roots2poly(pa);
+      end
+      zb = roots(b);
+      if isempty(zb)
+        z = pz.initObjectWithSize(1,0);
+        gainZ = 1;
+      else
+        [z, gainZ] = roots2poly(zb);
+      end
+      % computing gain coefficient
+      apos = a(a~=0);
+      bpos = b(b~=0);
+      if ~isempty(bpos) && ~isempty(apos)
+        Gain = bpos(1)/apos(1);
+      elseif ~isempty(apos)
+        Gain = 1/apos(1);
+      elseif ~isempty(bpos) % NB theoretically impossible to reach : SSM can't have more zeros than poles
+        Gain = bpos(1);
+      else
+        Gain = 0;
+      end
+      Gain = Gain / gainP * gainZ;
+      % constructing output pzm
+      name = [sys.name,'_',num2str(ii),':',num2str(oo)];
+      pzm_out(oo,ii) = pzmodel(plist(...
+        'gain', Gain, 'poles', p, 'zeros', z, 'name', name, ...
+        'inunits', inputunit(ii),  'ounits' ,outputunit(oo) ));
+      pzm_out(oo,ii).addHistory(ssm.getInfo(mfilename), pl , ssm_invars, sys.hist);
+    end
+  end
+  if nargout == numel(pzm_out)
+    for ii = 1:numel(pzm_out)
+      varargout{ii} = pzm_out(ii);
+    end
+  else
+    varargout{1} = pzm_out;
+  end
+end
+
+
+function varargout = roots2poly(roots)
+  poly = pz.initObjectWithSize(1,0);
+  i=1;
+  gain = 1;
+  while i < length(roots)+1
+    if isreal(roots(i))
+      poly = [poly pz(-roots(i)/2/pi)]; %#ok<AGROW>
+      gain = gain * abs(roots(i));
+      i = i+1;
+    else
+      f = norm(roots(i)/2/pi);%*sign(real(roots(i)));
+      Q = norm(roots(i))/abs(2*real(roots(i)));
+      poly = [poly pz(f,Q)]; %#ok<AGROW>
+      gain = gain * abs(roots(i))^2;
+      i = i+2; %#ok<FXSET>
+    end
+  end
+  varargout = {poly, gain};
+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.converter, '$Id: ssm2pzmodel.m,v 1.21 2011/04/08 08:56:23 hewitson Exp $', sets, pl);
+end
+
+%--------------------------------------------------------------------------
+% Get Default Plist
+%--------------------------------------------------------------------------
+function pl = getDefaultPlist()
+  pl = plist();
+  
+  p = param({'inputs', ['Specify the inputs. Give one of:<ul>'...
+    '<li>A cell-array of input port names.</li>'...
+    '<li>A cell-array of logical arrays specifying which input ports to use for each input block.</li>'...
+    '<li>A cell-array of double values specifying which input ports to use for each input block.<li>'...
+    '<li>The string ''ALL'' to use all inputs.']}, paramValue.STRING_VALUE('ALL'));
+  pl.append(p);
+  
+  p = param({'states', 'Specify the states. Specify the states as for the ''inputs'' parameter.'}, paramValue.STRING_VALUE('ALL'));
+  pl.append(p);
+  
+  p = param({'outputs', 'Specify the outputs. Specify the outputs as for the ''inputs'' parameter.'}, paramValue.STRING_VALUE('ALL'));
+  pl.append(p);
+end
+