--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@smodel/convol_integral.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,128 @@
+% CONVOL_INTEGRAL implements the convolution integral for smodel objects.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: CONVOL_INTEGRAL implements the convolution integral to evaluate
+% the time-domain response of smodel objects whose impulse response is h(t),
+% to input signals in_signal(t):
+%   o(t) = int(h(t1) * in_signal(t-t1), t1=0..t)        (1)
+%
+% CALL:        out = convol_integral(mdl, sig)
+%
+% INPUTS:      mdl    smodel with the time-domain impulse response of
+%                     the system
+%              sig    smodel with the time-domain applied signal
+%
+% OUTPUTS:     out    smodel with the time-domain response of the system
+%
+% NOTE:        Eq (1) assumes that in_signal(t<0) = 0
+%
+% <a href="matlab:utils.helper.displayMethodInfo('smodel', 'convol_integral')">Parameters Description</a>
+%
+% VERSION:     $Id: convol_integral.m,v 1.8 2011/04/08 08:56:29 hewitson Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function varargout = convol_integral(varargin)
+  
+  % Check if this is a call for parameters
+  if utils.helper.isinfocall(varargin{:})
+    varargout{1} = getInfo(varargin{3});
+    return
+  end
+  
+  % Check if the method was called by another method
+  callerIsMethod = utils.helper.callerIsMethod;
+  
+  % Collect input variable names
+  in_names = cell(size(varargin));
+  for ii = 1:nargin,in_names{ii} = inputname(ii);end
+  
+  % Collect all input smodels and plists
+  [mdls, smodel_invars, rest] = utils.helper.collect_objects(varargin(:), 'smodel', in_names);
+  pl        = utils.helper.collect_objects(rest(:), 'plist');
+   
+  % Merge with default plist
+  usepl = parse(pl, getDefaultPlist());
+    
+  % Check for the number of inputs
+  if numel(mdls) ~= 2
+    error('### Please provide an smodel with the system impulse response and an smodel with the signal')
+  else 
+    mdl = copy(mdls(1), false);
+    sig = copy(mdls(2), false);
+  end
+  
+  % Replace .* like expressions with * to allow symbolic evaluation
+  h = utils.prog.convertComString(mdl.expr.s, 'ToSymbolic');
+  in_signal = utils.prog.convertComString(sig.expr.s, 'ToSymbolic');
+
+  % Go symbolic now
+  syms t t1
+  % Input Signal
+  in_signal_t1 = sym(regexprep(in_signal,'\<t\>','t1'));
+  
+  % System impulse response
+  h_t_t1 = sym(regexprep(h,'\<t\>','(t-t1)'));
+  
+  % Calculate the system response via convolution (linear system)
+  out_s = simplify(int([h_t_t1 * in_signal_t1], t1, 0, t));
+  
+  % Go back to string after calcuation
+  out.expr.s = utils.prog.mup2mat(out_s);
+  
+  % Replace * like expressions with .* to allow numeric evaluation
+  out.expr.s = utils.prog.convertComString(out.expr.s , 'FromSymbolic');
+  
+  % Set variables, units
+  out.setXvar(sig.xvar);
+  out.setXunits(sig.xunits);
+  out.setYunits(mdl.yunits * sig.yunits);
+  
+  % Add history step
+  out.addHistory(getInfo('None'), usepl, [smodel_invars(:)], [mdls(:).hist]);
+  
+  % Set output
+  
+  % Single output
+  varargout{1} = out;
+end
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%                               Local Functions                               %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%--------------------------------------------------------------------------
+% Get Info Object
+%--------------------------------------------------------------------------
+function ii = getInfo(varargin)
+  
+  if nargin == 1 && strcmpi(varargin{1}, 'None')
+    sets = {};
+    pls  = [];
+  else
+    sets = {'Default'};
+    pls  = getDefaultPlist;
+  end
+  % Build info object
+  ii = minfo(mfilename, 'smodel', 'ltpda', utils.const.categories.op, '$Id: convol_integral.m,v 1.8 2011/04/08 08:56:29 hewitson Exp $', sets, pls);
+  ii.setArgsmin(2);
+end
+
+%--------------------------------------------------------------------------
+% Get Default Plist
+%--------------------------------------------------------------------------
+function plout = getDefaultPlist()
+  persistent pl;  
+  if ~exist('pl', 'var') || isempty(pl)
+    pl = buildplist();
+  end
+  plout = pl;  
+end
+
+function pl = buildplist()
+  pl = plist.EMPTY_PLIST;
+end
+
+
+
+