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comparison m-toolbox/classes/@ao/downsample.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 % DOWNSAMPLE AOs containing time-series data.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: DOWNSAMPLE AOs containing time-series data. All other AOs with
5 % no time-series data are skipped but appear in the output.
6 % Note that no anti-aliasing filter is applied to the
7 % original data!!!
8 % CALL: b = downsample(a, pl) - use plist to get parameters
9 % b = downsample(a1, a2, pl) - downsample both a1 and a2;
10 % b is then a 2x1 vector.
11 %
12 % <a href="matlab:utils.helper.displayMethodInfo('ao', 'downsample')">Parameters Description</a>
13 %
14 % EXAMPLES: 1) downsample x4; offset is set to default of 0
15 %
16 % >> p = plist('factor',4);
17 % >> b = downsample(a, p);
18 %
19 % 2) downsample x2 with 1 sample offset
20 %
21 % >> p = plist('factor',2,'offset',1);
22 % >> b = downsample(a,p);
23 %
24 %
25 % VERSION: $Id: downsample.m,v 1.34 2011/07/14 05:33:18 mauro Exp $
26 %
27 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
28
29 function varargout = downsample(varargin)
30
31 % Check if this is a call for parameters
32 if utils.helper.isinfocall(varargin{:})
33 varargout{1} = getInfo(varargin{3});
34 return
35 end
36
37 import utils.const.*
38 utils.helper.msg(msg.PROC3, 'running %s/%s', mfilename('class'), mfilename);
39
40 % Collect input variable names
41 in_names = cell(size(varargin));
42 for ii = 1:nargin,in_names{ii} = inputname(ii);end
43
44 % Collect all AOs
45 [as, ao_invars] = utils.helper.collect_objects(varargin(:), 'ao', in_names);
46 [pl, pl_invars] = utils.helper.collect_objects(varargin(:), 'plist', in_names);
47
48 % Decide on a deep copy or a modify
49 bs = copy(as, nargout);
50
51 % Combine plists
52 pl = parse(pl, getDefaultPlist);
53
54 % Get parameters from plist
55 offset = find(pl, 'offset');
56 factor = find(pl, 'factor');
57
58 % Checking downsampling value is valid
59 if isempty(factor)
60 error('### Please give a plist with a parameter ''Factor''.');
61 end
62
63 % Checking downsampling value is integer
64 if rem(factor, floor(factor)) ~= 0
65 warning('!!! Downsample factor should be an integer. Rounding. !!!');
66 factor = round(factor);
67 end
68
69 % Checking sample offset value
70 if isempty(offset)
71 warning('!!! No offset specified; using default of 0 samples !!!');
72 offset = 0;
73 end
74
75 if factor == 0
76 error('### The downsampling factor is zero. Please set a positive integer value.');
77 end
78
79 % Loop over input AOs
80 for jj = 1:numel(bs)
81 if isa(bs(jj).data, 'tsdata')
82 % get samples
83 ss = 1+offset;
84 samples = ss:factor:length(bs(jj).data.y);
85 % select samples
86 bs(jj).data.setXY(bs(jj).data.getX(samples), bs(jj).data.getY(samples));
87 % Set new sample rate
88 bs(jj).data.setFs(bs(jj).data.fs/factor);
89 % drop X vector again if we can
90 bs(jj).data.collapseX;
91 % set name
92 bs(jj).name = sprintf('downsample(%s)', ao_invars{jj});
93 % Add history
94 bs(jj).addHistory(getInfo('None'), pl, ao_invars(jj), bs(jj).hist);
95 % Clear the errors since they don't make sense anymore
96 clearErrors(bs(jj));
97 else
98 warning('!!! Downsample only works on tsdata objects. Skipping AO %s', ao_invars{jj});
99 end
100 end
101
102 % Set output
103 varargout = utils.helper.setoutputs(nargout, bs);
104 end
105
106 %--------------------------------------------------------------------------
107 % Get Info Object
108 %--------------------------------------------------------------------------
109 function ii = getInfo(varargin)
110 if nargin == 1 && strcmpi(varargin{1}, 'None')
111 sets = {};
112 pl = [];
113 else
114 sets = {'Default'};
115 pl = getDefaultPlist;
116 end
117 % Build info object
118 ii = minfo(mfilename, 'ao', 'ltpda', utils.const.categories.sigproc, '$Id: downsample.m,v 1.34 2011/07/14 05:33:18 mauro Exp $', sets, pl);
119 end
120
121 %--------------------------------------------------------------------------
122 % Get Default Plist
123 %--------------------------------------------------------------------------
124
125 function plout = getDefaultPlist()
126 persistent pl;
127 if ~exist('pl', 'var') || isempty(pl)
128 pl = buildplist();
129 end
130 plout = pl;
131 end
132
133 function pl = buildplist()
134
135 pl = plist();
136
137 % Factor
138 p = param({'factor', 'The decimation factor. Should be an integer.'}, {1, {1}, paramValue.OPTIONAL});
139 pl.append(p);
140
141 % Offset
142 p = param({'offset', 'The sample offset used in the decimation.'}, {1, {0}, paramValue.OPTIONAL});
143 pl.append(p);
144
145 end
146
147