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comparison m-toolbox/classes/@ao/cohere.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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children bc767aaa99a8
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-1:000000000000 0:f0afece42f48
1 % COHERE estimates the coherence between time-series objects
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: COHERE estimates the coherence between the
5 % time-series objects in the input analysis objects.
6 % The estimate is done by taking
7 % the ratio of the CPSD between the two inputs, Sxy, divided by
8 % the product of the PSDs of the inputs, Sxx and Syy,
9 % and is either magnitude-squared: (abs(Sxy))^2 / (Sxx * Syy)
10 % or complex value: Sxy / sqrt(Sxx * Syy)
11 % Here x is the first input, y is the second input
12 %
13 % CALL: b = cohere(a1,a2,pl)
14 %
15 % INPUTS: a1 - input analysis object
16 % a2 - input analysis object
17 % pl - input parameter list
18 %
19 % OUTPUTS: b - output analysis object
20 %
21 % <a href="matlab:utils.helper.displayMethodInfo('ao', 'cohere')">Parameters Description</a>
22 %
23 % VERSION: $Id: cohere.m,v 1.43 2011/04/08 08:56:16 hewitson Exp $
24 %
25 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
26
27 function varargout = cohere(varargin)
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 import utils.const.*
36 utils.helper.msg(msg.PROC3, 'running %s/%s', mfilename('class'), mfilename);
37
38 if nargout == 0
39 error('### cohere cannot be used as a modifier. Please give an output variable.');
40 end
41
42 % Collect input variable names
43 in_names = cell(size(varargin));
44 for ii = 1:nargin,in_names{ii} = inputname(ii);end
45
46 % Collect all AOs
47 [as, ao_invars] = utils.helper.collect_objects(varargin(:), 'ao', in_names);
48
49 % Apply defaults to plist
50 pl = applyDefaults(getDefaultPlist, varargin{:});
51
52 % Throw an error if input is not two AOs
53 if numel(as) ~= 2
54 error('### cohere only accepts two inputs AOs.');
55 end
56
57 % Compute coherence with xspec
58 scale_type = find(pl, 'Type');
59 switch lower(scale_type)
60 case 'c'
61 bs = xspec(as, pl, 'cohere', getInfo, ao_invars);
62 case 'ms'
63 bs = xspec(as, pl, 'mscohere', getInfo, ao_invars);
64 otherwise
65 error(['### Unknown coherence type: [' scale_type ']']);
66 end
67
68 % Set output
69 varargout{1} = bs;
70
71 end
72
73 %--------------------------------------------------------------------------
74 % Get Info Object
75 %--------------------------------------------------------------------------
76 function ii = getInfo(varargin)
77 if nargin == 1 && strcmpi(varargin{1}, 'None')
78 sets = {};
79 pl = [];
80 else
81 sets = {'Default'};
82 pl = getDefaultPlist();
83 end
84 % Build info object
85 ii = minfo(mfilename, 'ao', 'ltpda', utils.const.categories.sigproc, '$Id: cohere.m,v 1.43 2011/04/08 08:56:16 hewitson Exp $', sets, pl);
86 ii.setModifier(false);
87 ii.setArgsmin(2);
88 end
89
90 %--------------------------------------------------------------------------
91 % Get Default Plist
92 %--------------------------------------------------------------------------
93
94 function plout = getDefaultPlist()
95 persistent pl;
96 if ~exist('pl', 'var') || isempty(pl)
97 pl = buildplist();
98 end
99 plout = pl;
100 end
101
102 function pl = buildplist()
103
104 % General plist for Welch-based, linearly spaced spectral estimators
105 pl = plist.WELCH_PLIST;
106
107 % Type
108 p = param({'Type',['type of output scaling. Choose from:<ul>', ...
109 '<li>MS - Magnitude-Squared Coherence:<br><tt>(abs(Sxy))^2 / (Sxx * Syy)</tt></li>', ...
110 '<li>C - Complex Coherence:<br><tt>Sxy / sqrt(Sxx * Syy)</tt></li></ul>']}, {1, {'C', 'MS'}, paramValue.SINGLE});
111 pl.append(p);
112
113 end
114