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comparison m-toolbox/classes/@smodel/convol_integral.m @ 0:f0afece42f48

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author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
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1 % CONVOL_INTEGRAL implements the convolution integral for smodel objects.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: CONVOL_INTEGRAL implements the convolution integral to evaluate
5 % the time-domain response of smodel objects whose impulse response is h(t),
6 % to input signals in_signal(t):
7 % o(t) = int(h(t1) * in_signal(t-t1), t1=0..t) (1)
8 %
9 % CALL: out = convol_integral(mdl, sig)
10 %
11 % INPUTS: mdl smodel with the time-domain impulse response of
12 % the system
13 % sig smodel with the time-domain applied signal
14 %
15 % OUTPUTS: out smodel with the time-domain response of the system
16 %
17 % NOTE: Eq (1) assumes that in_signal(t<0) = 0
18 %
19 % <a href="matlab:utils.helper.displayMethodInfo('smodel', 'convol_integral')">Parameters Description</a>
20 %
21 % VERSION: $Id: convol_integral.m,v 1.8 2011/04/08 08:56:29 hewitson Exp $
22 %
23 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
24
25 function varargout = convol_integral(varargin)
26
27 % Check if this is a call for parameters
28 if utils.helper.isinfocall(varargin{:})
29 varargout{1} = getInfo(varargin{3});
30 return
31 end
32
33 % Check if the method was called by another method
34 callerIsMethod = utils.helper.callerIsMethod;
35
36 % Collect input variable names
37 in_names = cell(size(varargin));
38 for ii = 1:nargin,in_names{ii} = inputname(ii);end
39
40 % Collect all input smodels and plists
41 [mdls, smodel_invars, rest] = utils.helper.collect_objects(varargin(:), 'smodel', in_names);
42 pl = utils.helper.collect_objects(rest(:), 'plist');
43
44 % Merge with default plist
45 usepl = parse(pl, getDefaultPlist());
46
47 % Check for the number of inputs
48 if numel(mdls) ~= 2
49 error('### Please provide an smodel with the system impulse response and an smodel with the signal')
50 else
51 mdl = copy(mdls(1), false);
52 sig = copy(mdls(2), false);
53 end
54
55 % Replace .* like expressions with * to allow symbolic evaluation
56 h = utils.prog.convertComString(mdl.expr.s, 'ToSymbolic');
57 in_signal = utils.prog.convertComString(sig.expr.s, 'ToSymbolic');
58
59 % Go symbolic now
60 syms t t1
61 % Input Signal
62 in_signal_t1 = sym(regexprep(in_signal,'\<t\>','t1'));
63
64 % System impulse response
65 h_t_t1 = sym(regexprep(h,'\<t\>','(t-t1)'));
66
67 % Calculate the system response via convolution (linear system)
68 out_s = simplify(int([h_t_t1 * in_signal_t1], t1, 0, t));
69
70 % Go back to string after calcuation
71 out.expr.s = utils.prog.mup2mat(out_s);
72
73 % Replace * like expressions with .* to allow numeric evaluation
74 out.expr.s = utils.prog.convertComString(out.expr.s , 'FromSymbolic');
75
76 % Set variables, units
77 out.setXvar(sig.xvar);
78 out.setXunits(sig.xunits);
79 out.setYunits(mdl.yunits * sig.yunits);
80
81 % Add history step
82 out.addHistory(getInfo('None'), usepl, [smodel_invars(:)], [mdls(:).hist]);
83
84 % Set output
85
86 % Single output
87 varargout{1} = out;
88 end
89
90 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
91 % Local Functions %
92 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
93
94 %--------------------------------------------------------------------------
95 % Get Info Object
96 %--------------------------------------------------------------------------
97 function ii = getInfo(varargin)
98
99 if nargin == 1 && strcmpi(varargin{1}, 'None')
100 sets = {};
101 pls = [];
102 else
103 sets = {'Default'};
104 pls = getDefaultPlist;
105 end
106 % Build info object
107 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);
108 ii.setArgsmin(2);
109 end
110
111 %--------------------------------------------------------------------------
112 % Get Default Plist
113 %--------------------------------------------------------------------------
114 function plout = getDefaultPlist()
115 persistent pl;
116 if ~exist('pl', 'var') || isempty(pl)
117 pl = buildplist();
118 end
119 plout = pl;
120 end
121
122 function pl = buildplist()
123 pl = plist.EMPTY_PLIST;
124 end
125
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