--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@ao/downsample.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,147 @@
+% DOWNSAMPLE AOs containing time-series data.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: DOWNSAMPLE AOs containing time-series data. All other AOs with
+%              no time-series data are skipped but appear in the output.
+%              Note that no anti-aliasing filter is applied to the
+%              original data!!!
+% CALL:        b = downsample(a, pl)      - use plist to get parameters
+%              b = downsample(a1, a2, pl) - downsample both a1 and a2;
+%                                           b is then a 2x1 vector.
+%
+% <a href="matlab:utils.helper.displayMethodInfo('ao', 'downsample')">Parameters Description</a>
+%
+% EXAMPLES:   1) downsample x4; offset is set to default of 0
+%
+%                >> p = plist('factor',4);
+%                >> b = downsample(a, p);
+%
+%             2) downsample x2 with 1 sample offset
+%
+%                >> p = plist('factor',2,'offset',1);
+%                >> b = downsample(a,p);
+%
+%
+% VERSION:     $Id: downsample.m,v 1.34 2011/07/14 05:33:18 mauro Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function varargout = downsample(varargin)
+
+  % Check if this is a call for parameters
+  if utils.helper.isinfocall(varargin{:})
+    varargout{1} = getInfo(varargin{3});
+    return
+  end
+
+  import utils.const.*
+  utils.helper.msg(msg.PROC3, 'running %s/%s', mfilename('class'), mfilename);
+  
+  % Collect input variable names
+  in_names = cell(size(varargin));
+  for ii = 1:nargin,in_names{ii} = inputname(ii);end
+
+  % Collect all AOs
+  [as, ao_invars] = utils.helper.collect_objects(varargin(:), 'ao', in_names);
+  [pl, pl_invars] = utils.helper.collect_objects(varargin(:), 'plist', in_names);
+
+  % Decide on a deep copy or a modify
+  bs = copy(as, nargout);
+
+  % Combine plists
+  pl = parse(pl, getDefaultPlist);
+
+  % Get parameters from plist
+  offset = find(pl, 'offset');
+  factor = find(pl, 'factor');
+
+  % Checking downsampling value is valid
+  if isempty(factor)
+    error('### Please give a plist with a parameter ''Factor''.');
+  end
+
+  % Checking downsampling value is integer
+  if rem(factor, floor(factor)) ~= 0
+    warning('!!! Downsample factor should be an integer. Rounding. !!!');
+    factor = round(factor);
+  end
+
+  % Checking sample offset value
+  if isempty(offset)
+    warning('!!! No offset specified; using default of 0 samples !!!');
+    offset = 0;
+  end
+
+  if factor == 0
+    error('### The downsampling factor is zero. Please set a positive integer value.');
+  end
+  
+  % Loop over input AOs
+  for jj = 1:numel(bs)
+    if isa(bs(jj).data, 'tsdata')
+      % get samples
+      ss = 1+offset;
+      samples = ss:factor:length(bs(jj).data.y);
+      % select samples
+      bs(jj).data.setXY(bs(jj).data.getX(samples), bs(jj).data.getY(samples));
+      % Set new sample rate
+      bs(jj).data.setFs(bs(jj).data.fs/factor);
+      % drop X vector again if we can
+      bs(jj).data.collapseX;
+      % set name
+      bs(jj).name = sprintf('downsample(%s)', ao_invars{jj});
+      % Add history
+      bs(jj).addHistory(getInfo('None'), pl, ao_invars(jj), bs(jj).hist);
+      % Clear the errors since they don't make sense anymore
+      clearErrors(bs(jj));
+    else
+      warning('!!! Downsample only works on tsdata objects. Skipping AO %s', ao_invars{jj});
+    end
+  end
+
+  % Set output
+  varargout = utils.helper.setoutputs(nargout, bs);
+end
+
+%--------------------------------------------------------------------------
+% Get Info Object
+%--------------------------------------------------------------------------
+function ii = getInfo(varargin)
+  if nargin == 1 && strcmpi(varargin{1}, 'None')
+    sets = {};
+    pl   = [];
+  else
+    sets = {'Default'};
+    pl   = getDefaultPlist;
+  end
+  % Build info object
+  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);
+end
+
+%--------------------------------------------------------------------------
+% Get Default Plist
+%--------------------------------------------------------------------------
+
+function plout = getDefaultPlist()
+  persistent pl;  
+  if ~exist('pl', 'var') || isempty(pl)
+    pl = buildplist();
+  end
+  plout = pl;  
+end
+
+function pl = buildplist()
+  
+  pl = plist();
+  
+  % Factor
+  p = param({'factor', 'The decimation factor. Should be an integer.'}, {1, {1}, paramValue.OPTIONAL});
+  pl.append(p);
+  
+  % Offset
+  p = param({'offset', 'The sample offset used in the decimation.'}, {1, {0}, paramValue.OPTIONAL});
+  pl.append(p);
+  
+end
+
+