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comparison m-toolbox/classes/@ssm/resp.m @ 0:f0afece42f48

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Import.
author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
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-1:000000000000 0:f0afece42f48
1 % RESP gives the timewise impulse response of a statespace model.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: RESP gives the timewise impulse response of a statespace
5 % model.
6 %
7 % CALL: mat_out = resp(sys, plist_inputs)
8 %
9 % INPUTS:
10 % - sys, (array of) ssm object
11 %
12 % plist with parameters 'inputs', 'states' and 'outputs' to indicate which
13 % inputs, states and outputs variables are taken in account. This requires
14 % proper variable naming. If a variable called appears more that once it
15 % will be used once only.
16 %
17 % OUTPUTS:
18 % - mat_out contains the timewise response (one for each input)
19 %
20 % <a href="matlab:utils.helper.displayMethodInfo('ssm', 'resp')">Parameters Description</a>
21 %
22 % VERSION: $Id: resp.m,v 1.27 2011/04/17 21:28:06 adrien Exp $
23 %
24 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
25
26 function varargout = resp(varargin)
27 %% starting initial checks
28
29 % use the caller is method flag
30 callerIsMethod = utils.helper.callerIsMethod;
31
32 % Check if this is a call for parameters
33 if utils.helper.isinfocall(varargin{:})
34 varargout{1} = getInfo(varargin{3});
35 return
36 end
37
38 utils.helper.msg(utils.const.msg.MNAME, ['running ', mfilename]);
39
40 % checking number of inputs work data
41 in_names = cell(size(varargin));
42 for oo = 1:nargin,in_names{oo} = inputname(oo);end
43
44 [sys, ssm_invars, rest] = utils.helper.collect_objects(varargin(:), 'ssm', in_names);
45 [pl, ssm_invars2, rest] = utils.helper.collect_objects(rest(:), 'plist', in_names);
46 if ~isempty(rest)
47 pl = combine(pl, plist(rest{:}));
48 end
49 pl = combine(pl, getDefaultPlist());
50
51
52 %% begin function body
53 if numel(sys)>1
54 error('ssm/resp only works with a single statespace model.')
55 end
56
57 if ~sys.isnumerical
58 error('The input system should be numeric.')
59 end
60
61 %% modifying input ssm
62 if sys.timestep == 0
63 sys = copy(sys, true);
64 sys.modifyTimeStep('newtimestep', 0.1);
65 warning('Warning : time-continuous ssm was discretized with a time-step of 0.1s per default') %#ok<WNTAG>
66 end
67
68 %% getting duration of the response
69 tmax = find(pl, 'tmax');
70 if sys.isStable && (tmax == -1)
71 pl_s = settlingTime(sys, pl);
72 timeMax = min(find(pl_s, 'SETTLING_TIME'), 1e5);
73 timeMax = nextPow2( 12* timeMax);
74 else
75 timeMax = nextPow2( tmax./sys.timestep);
76 end
77
78 %% deriving and initializing matrices
79 if find(pl, 'reorganize')
80 sys = copy(sys, true);
81 sys = reorganize(sys, pl, 'set', 'for resp', 'internal', 'internal');
82 end
83
84 A = sys.amats{1,1};
85 B = sys.bmats{1,1};
86 C = sys.cmats{2,1};
87 Cstates = sys.cmats{1,1};
88 D = sys.dmats{2,1};
89 Ts = sys.timestep;
90
91 Ninputs = size(B,2);
92 Noutputs = size(C,1);
93 Nss = size(A,1);
94 NssOut = size(Cstates,1);
95
96 %% collecting data before saving in loop
97 aos = ao.initObjectWithSize(Noutputs+NssOut, Ninputs);
98 inhist = sys.hist;
99
100 inputType = find(pl, 'response');
101
102 for ii=1:Ninputs
103
104 %% depending on user option, compute response for one input only
105 if strcmpi( inputType, 'IMPULSE')
106 stateVect = zeros(Nss,2^timeMax);
107 stateVect(:,1) = B(:,ii)/sys.timestep;
108 a = A;
109 for k=1:timeMax
110 p = k-1;
111 stateVect(:,1:2^k) = [stateVect(:,1:2^p) a*stateVect(:,1:2^p)];
112 a = a*a;
113 end
114 outputVect = C*stateVect;
115 outputVect(:,1) = outputVect(:,1) + D(:,ii);
116 stateVect = Cstates*stateVect;
117 respName = 'Impulse';
118
119 elseif strcmpi( inputType, 'STEP')
120 stateVect = zeros(Nss,2^timeMax);
121 stateVect(:,1) = B(:,ii);
122 stateBasis = B(:,ii);
123 outputVect = zeros(Noutputs,2^timeMax);
124 outputVect(:,1) = D(:,ii);
125 a_powP = A;
126 for k=1:timeMax
127 p = k-1;
128 outputVect(:,1:2^k) = [ outputVect(:,1:2^p) outputVect(:,1:2^p) ];
129 lastStates = stateVect(:,1:2^p);
130 stateVect(:,(2^p+1):2^k) = a_powP*lastStates + diag(stateBasis)*ones(Nss, 2^p) ;
131 % update iterative matrices
132 stateBasis = a_powP*stateBasis + stateBasis;
133 a_powP = a_powP*a_powP;
134 end
135 outputVect = C*stateVect + outputVect;
136 outputVect = [ zeros(Noutputs,1) outputVect]; %#ok<AGROW>
137 stateVect = Cstates*stateVect;
138 respName = 'Step';
139
140 else
141 error(['Option ''response'' does not accept the value' inputType]);
142 end
143
144 %% storing response in aos for one input only
145
146 for oo=1:NssOut;
147 aos(oo,ii).setData(tsdata( stateVect(oo,:), 1/Ts));
148 aos(oo,ii).setName([sys.inputs(1).ports(ii).name '->' sys.outputs(1).ports(oo).name]);
149 aos(oo,ii).setXunits('s');
150 aos(oo,ii).setYunits(sys.outputs(1).ports(oo).units);
151 aos(oo,ii).setDescription([respName ' response from input ' , sys.inputs(1).ports(ii).name , 'to output ', sys.outputs(1).ports(oo).name]);
152 aos(oo,ii).setT0(sys.timestep);
153 end
154 for oo=1:Noutputs;
155 aos(NssOut+oo,ii).setData(tsdata( outputVect(oo,:), 1/Ts));
156 aos(NssOut+oo,ii).setName([sys.inputs(1).ports(ii).name '->' sys.outputs(2).ports(oo).name]);
157 aos(NssOut+oo,ii).setXunits('s');
158 aos(NssOut+oo,ii).setYunits(sys.outputs(2).ports(oo).units);
159 aos(NssOut+oo,ii).setDescription([respName ' response from input ' , sys.inputs(1).ports(ii).name , 'to output ', sys.outputs(2).ports(oo).name]);
160 aos(NssOut+oo,ii).setT0(sys.timestep);
161 end
162 end
163
164 %% construct output matrix object
165 out = matrix(aos);
166 if callerIsMethod
167 % do nothing
168 else
169 myinfo = getInfo('None');
170 out.addHistory(myinfo, pl , ssm_invars(1), inhist );
171 end
172
173 %% Set output depending on nargout
174 if nargout == 1;
175 varargout = {out};
176 elseif nargout == 2;
177 varargout = {out plist_out};
178 elseif nargout == 0;
179 iplot(aos);
180 else
181 error('Wrong number of outputs')
182 end
183 end
184
185 %--------------------------------------------------------------------------
186 % Get Info Object
187 %--------------------------------------------------------------------------
188 function oo = getInfo(varargin)
189
190 if nargin == 1 && strcmpi(varargin{1}, 'None')
191 sets = {};
192 pl = [];
193 else
194 sets = {'Default'};
195 pl = getDefaultPlist;
196 end
197 % Build info object
198 oo = minfo(mfilename, 'ssm', 'ltpda', utils.const.categories.sigproc, '$Id: resp.m,v 1.27 2011/04/17 21:28:06 adrien Exp $', sets, pl);
199 end
200
201 %--------------------------------------------------------------------------
202 % Get Default Plist
203 %--------------------------------------------------------------------------
204
205 function pl = getDefaultPlist()
206 pl = ssm.getInfo('reorganize', 'for resp').plists;
207 pl.remove('set');
208
209 p = param({'response', 'Specify the type of response wanted'},{1, {'impulse', 'step'}, paramValue.SINGLE} );
210 pl.append(p);
211
212 p = param({'tmax', 'Specify the duration of response wanted [s] (automatically set if not specified by user, and system is stable)'},-1 );
213 pl.append(p);
214
215 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);
216 pl.append(p);
217
218
219 end