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−% MINUS implements subtraction operator for cdata objects.
+
−%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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−%
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−% DESCRIPTION: MINUS implements subtraction operator for two cdata objects.
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−%
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−% CALL:        a = d1-d2
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−%              a = minus(d1,d2);
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−%
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−% <a href="matlab:utils.helper.displayMethodInfo('cdata', 'minus')">Parameters Description</a>
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−%
+
−% VERSION:     $Id: minus.m,v 1.3 2011/04/08 08:56:34 hewitson Exp $
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−%
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−%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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−
+
−function varargout = minus(varargin)
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−  
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−  % get two data objects
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−  d1 = copy(varargin{1}, nargout);
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−  d2 = copy(varargin{2}, nargout);
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−  
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−  % check units
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−  d1.yunits.simplify();
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−  d2.yunits.simplify();
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−  
+
−  if ~isempty(d1.yunits.strs) && ~isempty(d2.yunits.strs) && d1.yunits ~= d2.yunits
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−    error('### When subtracting two data objects, the yunits must be the same');
+
−  end
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−  
+
−  % add the data
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−  dout = applyoperator(d1,d2,'minus');
+
−  
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−  % handle units: since both are the same, we take the first non-empty unit
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−  if isempty(d1.yunits.strs)
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−    dout.yunits = d2.yunits;
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−  else
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−    dout.yunits = d1.yunits;
+
−  end
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−  
+
−  % handle errors
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−  err = @(err1, err2) sqrt(err1 .^2 + err2.^2);
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−  if ~isempty(d1.dy) || ~isempty(d2.dy)    
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−    if isempty(d1.dy)
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−      d1.dy = zeros(size(d2.dy));
+
−    end
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−    if isempty(d2.dy)
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−      d2.dy = zeros(size(d1.dy));
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−    end    
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−    dout.dy = err(d1.dy, d2.dy);
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−  else
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−    dout.dy = [];
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−  end
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−
+
−  
+
−  % Single output
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−  varargout{1} = dout;
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−  
+
−end
+
−