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comparison m-toolbox/classes/@ssm/CPSD.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 % CPSD computes the output theoretical CPSD shape with given inputs.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: CPSD computes the output theoretical CPSD shape with given inputs.
5 % Unlike PSD, it returns the total contribution and takes
6 % input vectors/square matrices of objects
7 %
8 % CALL: [mat_out] = CPSD(sys, pl)
9 %
10 % INPUTS:
11 % - sys, (array of) ssm object
12 %
13 % OUTPUTS:
14 % _ mat_out contains specified returned aos
15 %
16 % <a href="matlab:utils.helper.displayMethodInfo('ssm', 'CPSD')">Parameters Description</a>
17 %
18 % VERSION: $Id: CPSD.m,v 1.11 2011/04/27 17:21:27 adrien Exp $
19 %
20 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
21
22 function varargout = CPSD(varargin)
23
24 %% starting initial checks
25
26 % use the caller is method flag
27 callerIsMethod = utils.helper.callerIsMethod;
28
29 % Check if this is a call for parameters
30 if utils.helper.isinfocall(varargin{:})
31 varargout{1} = getInfo(varargin{3});
32 return
33 end
34
35 utils.helper.msg(utils.const.msg.MNAME, ['running ', mfilename]);
36
37 % Collect input variable names
38 in_names = cell(size(varargin));
39 for ii = 1:nargin,in_names{ii} = inputname(ii);end
40
41 % Collect all SSMs and plists
42 [sys, ssm_invars, rest] = utils.helper.collect_objects(varargin(:), 'ssm', in_names);
43 [pl, invars2, rest] = utils.helper.collect_objects(rest(:), 'plist');
44 if ~isempty(rest)
45 pl = combine(pl, plist(rest{:}));
46 end
47 pl = combine(pl, getDefaultPlist());
48
49 %%% Internal call: Only one object + don't look for a plist
50 internal = strcmp(varargin{end}, 'internal');
51
52 %% begin function body
53
54 %% retrieve system infos
55
56 if numel(sys)~=1
57 error('noisespectrum needs exactly one ssm as an input')
58 end
59 if ~sys.isnumerical
60 error(['error because system ',sys.name,' is not numerical']);
61 end
62 if ~sys.isStable
63 error('input ssm is not stable!')
64 end
65 if sys.timestep==0
66 timestep = 1;
67 else
68 timestep = sys.timestep;
69 end
70 if ~internal
71 inhist = sys.hist;
72 end
73
74 %% modifying system's ordering
75 if find(pl, 'reorganize')
76 sys = reorganize(sys, pl, 'set', 'for cpsd', 'internal', 'internal');
77 end
78
79 %% collecting functions i/o data
80 aos_in = find(pl, 'aos');
81 PZ_in = find(pl, 'PZmodels');
82 cov_in = find(pl, 'covariance');
83 cpsd_in = find(pl, 'CPSD');
84 noise_in = blkdiag(cov_in, cpsd_in/(timestep*2));
85 [U1,S1,V1] = svd(noise_in.'); %#ok<NASGU>
86 noise_mat = U1*sqrt(S1);
87
88 %% getting system's i/o sizes
89 inputSizes = sys.inputsizes;
90 outputSizes = sys.outputsizes; %#ok<NASGU>
91
92 Naos_in = inputSizes(1);
93 NPZmodels = inputSizes(3);
94
95 %% retrieving frequency vector
96 if isempty(Naos_in)==0
97 f1 = find(pl,'f1');
98 f2 = find(pl,'f2');
99 NFreqs = find(pl,'nf');
100 if isempty(f1) || isempty(f2)|| isempty(NFreqs)
101 error('### Please specify frequency vector a start and stop frequency .');
102 else
103 freqs = 10.^linspace(log10(f1), log10(f2), NFreqs);
104 end
105 else
106 freqs = aos_in(1).x;
107 end
108
109 %% checking frequency vector
110 for i=2:numel(aos_in)
111 if ~isequal(freqs,aos_in(i).x)
112 error('there exist different frequency vectors');
113 end
114 end
115
116 %% reshape pzmodels and aos for input cross-spectra
117 if numel(PZ_in)==NPZmodels
118 PZfull = false;
119 PZdata = zeros(NPZmodels,NFreqs);
120 for i=1:NPZmodels
121 a = resp(PZ_in(i), freqs);
122 PZdata(i,:) = reshape(a.y,[1,NFreqs]) ;
123 end
124 elseif size(PZ_in,1)==NPZmodels && size(PZ_in,2)==NPZmodels
125 PZfull = true;
126 PZdata = zeros(Npzmodels,Npzmodels,NFreqs);
127 for i=1:NPZmodels
128 for j=1:Npzmodels
129 a = resp(PZ_in(i,j), freqs);
130 PZdata(i,j,:) = reshape(a.y,[1,NFreqs]) ;
131 end
132 end
133 else
134 error('Wrong size for field PZ_in')
135 end
136
137 if numel(aos_in)==Naos_in
138 AOfull = false;
139 AOdata = zeros(Naos_in,NFreqs);
140 for i=1:Naos_in
141 AOdata(i,:) = reshape(aos_in(i).y,[1,NFreqs]) ;
142 end
143 elseif size(aos_in,1)==Naos_in && size(aos_in,2)==Naos_in
144 AOfull = true;
145 AOdata = zeros(Naos_in,Naos_in,NFreqs);
146 for i=1:Naos_in
147 for j=1:Naos_in
148 AOdata(i,j,:) = reshape(aos_in(i,j).y,[1,NFreqs]) ;
149 end
150 end
151 else
152 error('Wrong size for field aos_in')
153 end
154
155 %% SSM Transfer function
156 [a, b, c, d, Ts, InputName, StateName, OutputName,...
157 inputvarunits, ssvarunits, outputvarunits] = double(sys); %#ok<ASGLU>
158 resps = ssm.doBode(a, b, c, d, 2*pi*freqs, Ts);
159 Noutputs = numel(OutputName);
160
161 %% power for each frequency with SVD computation
162 Result = zeros(Noutputs,Noutputs,NFreqs);
163
164 for i_freq=1:NFreqs
165 %% contribution from aos, testing positiveness
166 if AOfull
167 PowAO = squeeze(AOdata(:,:,i_freq));
168 [U1,S1,V1] = svd(PowAO.'); %#ok<NASGU>
169 if (sum(S1<0)>0)
170 error('AO covariance matrix is not positive')
171 end
172 AmpAO = U1*sqrt(S1);
173 else
174 if (sum(AOdata(:,i_freq)<0)>0)
175 error('non positive covariance')
176 end
177 AmpAO = diag(AOdata(:,i_freq).^0.5);
178 end
179 %% contribution from PZmodels, testing positiveness
180 if PZfull
181 PowPZ = squeeze(PZdata(:,:,i_freq));
182 [U1,S1,V1] = svd(PowPZ.'); %#ok<NASGU>
183 if (sum(S1<0)>0)
184 error('PZmodels covariance matrix is not positive')
185 end
186 AmpPZ = U1*sqrt(S1);
187 else
188 if (sum(PZdata(:,i_freq)<0)>0)
189 error('non positive covariance')
190 end
191 AmpPZ = diag(PZdata(:,i_freq).^0.5);
192 end
193 %% summing all three contributions sources, computing CPSD
194 Amp = blkdiag(AmpAO, noise_mat, AmpPZ);
195 RespLoc = squeeze(resps(:,:,i_freq));
196 noise = RespLoc * Amp * (RespLoc*Amp)';
197 Result(:,:,i_freq) = real(noise) * (2*timestep); % 2 correction added here
198 end
199
200 %% saving in aos
201 ao_out = ao.initObjectWithSize(Noutputs, Noutputs);
202
203 for io=1:Noutputs
204 for jo=1:Noutputs
205 ao_out(io,jo).setData(fsdata(freqs, squeeze(Result(jo,io,:))));
206 if io~=jo
207 ao_out(io,jo).setName( ['Cross PSD of ', OutputName{jo}, ' and ', OutputName{io}]);
208 else
209 ao_out(io,jo).setName( ['PSD of ' , OutputName{jo}]);
210 end
211 ao_out(io,jo).setXunits('Hz');
212 ao_out(io,jo).setYunits(outputvarunits(io)*outputvarunits(jo)/unit('Hz'));
213 if io~=jo
214 ao_out(io,jo).setDescription( ['Cross PSD of ', OutputName{jo}, ' and ', OutputName{io}]);
215 else
216 ao_out(io,jo).setDescription( ['PSD of ' , OutputName{jo}]);
217 end
218 end
219 end
220
221 %% construct output matrix object
222 out = matrix(ao_out);
223 if callerIsMethod
224 % do nothing
225 else
226 myinfo = getInfo('None');
227 out.addHistory(myinfo, pl , ssm_invars(1), inhist );
228 end
229
230 %% Set output depending on nargout
231 if nargout == 1;
232 varargout = {out};
233 elseif nargout == 0;
234 iplot(ao_out);
235 else
236 error('Wrong number of outputs')
237 end
238 end
239
240
241 %--------------------------------------------------------------------------
242 % Get Info Object
243 %--------------------------------------------------------------------------
244 function ii = getInfo(varargin)
245
246 if nargin == 1 && strcmpi(varargin{1}, 'None')
247 sets = {};
248 pl = [];
249 else
250 sets = {'Default'};
251 pl = getDefaultPlist;
252 end
253 % Build info object
254 ii = minfo(mfilename, 'ssm', 'ltpda', utils.const.categories.op, '$Id: CPSD.m,v 1.11 2011/04/27 17:21:27 adrien Exp $', sets, pl);
255
256 end
257
258 %--------------------------------------------------------------------------
259 % Get Default Plist
260 %--------------------------------------------------------------------------
261 function pl = getDefaultPlist()
262 pl = ssm.getInfo('reorganize', 'for CPSD').plists;
263 pl.remove('set');
264
265 p = param({'covariance', 'The covariance of this noise between input ports for the <i>time-discrete</i> noise model.'}, []);
266 pl.append(p);
267
268 p = param({'CPSD', 'The one sided cross-psd of the white noise between input ports.'}, []);
269 pl.append(p);
270
271 p = param({'aos', 'An array of input AOs, The power spectrum of this noise between input ports for the <i>time-continuous</i> noise model.'}, ao.initObjectWithSize(1,0));
272 pl.append(p);
273
274 p = param({'PZmodels', 'An array of input pzmodels for noise filtering'}, paramValue.DOUBLE_VALUE(zeros(0,1)));
275 pl.append(p);
276
277 p = param({'reorganize', 'When set to 0, this means the ssm does not need be modified to match the requested i/o. Faster but dangerous!'}, paramValue.TRUE_FALSE);
278 pl.append(p);
279
280 p = param({'f2', 'The maximum frequency. Default is Nyquist or 1Hz.'}, paramValue.EMPTY_DOUBLE);
281 pl.append(p);
282
283 p = param({'f1', 'The minimum frequency. Default is f2*1e-5.'}, paramValue.EMPTY_DOUBLE);
284 pl.append(p);
285
286 p = param({'nf', 'The number of frequency bins. Frequencies are scale logarithmically'}, paramValue.DOUBLE_VALUE(200));
287 pl.append(p);
288
289 end
290