Description of dataset

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dataset

PURPOSE

DATASET Constructs a dataset object (conform to DSDML)

SYNOPSIS

function DS = dataset(varargin)

DESCRIPTION

DATASET Constructs a dataset object (conform to DSDML)

 $ Syntax $
   - DS = dataset()
   - DS = dataset(attribs)
   - DS = dataset(attrname1, attrvalue1, ...)
   - DS = dataset(filename)
   - DS = dataset('from:fns', name, format, fns, labels);

 $ Arguments $
   - DS:           the dataset constructed
   - attribs:      the struct of the attributes
   - filename:     the DSDML file describing the data set.

 $ Description $
   - DS = dataset() constructs an empty data set with default attributes.
   
   - DS = dataset(attribs) constructs an empty data set with some 
     attributes specified in the struct attribs.

   - DS = dataset(attrname1, attrvalue1, ...) constructs an empty 
     dataset with some attributes specified in the attribute list.

   - DS = dataset(filename) constructs the dataset by loading it from
     a DSDML file.

   - DS = dataset('from:fns', name, format, fns, labels) constructs the 
     dataset by using construct_dataset_fns.m

 $ History $
   - Created by Dahua Lin on Jul 23rd, 2006

CROSS-REFERENCE INFORMATION

This function calls:

• construct_dataset_filenames CONSTRUCT_DATASET_FNS Constructs Dataset object from filenames
• readfile READFILE Reads the dataset from DSDML file

This function is called by:

• slimgsetprep SLIMGSETPREP organizes the images in a MATLAB friendly way

SUBFUNCTIONS

• function DS = dataset_setattribs(DS, n, attrnames, attrvalues)

SOURCE CODE

0001 function DS = dataset(varargin)
0002 %DATASET Constructs a dataset object (conform to DSDML)
0003 %
0004 % $ Syntax $
0005 %   - DS = dataset()
0006 %   - DS = dataset(attribs)
0007 %   - DS = dataset(attrname1, attrvalue1, ...)
0008 %   - DS = dataset(filename)
0009 %   - DS = dataset('from:fns', name, format, fns, labels);
0010 %
0011 % $ Arguments $
0012 %   - DS:           the dataset constructed
0013 %   - attribs:      the struct of the attributes
0014 %   - filename:     the DSDML file describing the data set.
0015 %
0016 % $ Description $
0017 %   - DS = dataset() constructs an empty data set with default attributes.
0018 %
0019 %   - DS = dataset(attribs) constructs an empty data set with some
0020 %     attributes specified in the struct attribs.
0021 %
0022 %   - DS = dataset(attrname1, attrvalue1, ...) constructs an empty
0023 %     dataset with some attributes specified in the attribute list.
0024 %
0025 %   - DS = dataset(filename) constructs the dataset by loading it from
0026 %     a DSDML file.
0027 %
0028 %   - DS = dataset('from:fns', name, format, fns, labels) constructs the
0029 %     dataset by using construct_dataset_fns.m
0030 %
0031 % $ History $
0032 %   - Created by Dahua Lin on Jul 23rd, 2006
0033 %
0034 
0035 
0036 %% Parse the input arguments
0037 
0038 cway = '';
0039 if ~isempty(varargin)
0040     if length(varargin) == 1
0041         if ischar(varargin{1})
0042             cway = 'file';
0043             filename = varargin{1};
0044         elseif isstruct(varargin{1})
0045             cway = 'attr.struct';
0046             attrs = varargin{1};
0047         else
0048             error('dsdml:invalidarg', ...
0049                 'Invalid input arguments for dataset construction');
0050         end
0051     else
0052         switch varargin{1}
0053             case 'from:fns'
0054                 cway = 'from:fns';
0055                 params = varargin(2:end);
0056             otherwise
0057                 cway = 'attr.list';
0058                 attrs = varargin;
0059         end        
0060     end
0061 end
0062                     
0063 
0064 %% Initialize the default empty dataset
0065 
0066 DS.version = '1.00';
0067 DS.name = [];
0068 DS.unittype = [];
0069 DS.format = [];
0070 DS.author = [];
0071 DS.description = [];
0072 DS.attribs = [];
0073 DS.units = [];
0074 
0075 DS = class(DS, 'dataset');
0076 
0077 %% Further construction
0078 
0079 switch cway
0080     case 'file'        
0081         DS = readfile(DS, filename);
0082         
0083     case 'attr.struct'
0084         attrnames = fieldnames(attrs);
0085         nattrs = length(attrnames);
0086         attrvalues = cell(nattrs, 1);
0087         for i = 1 : nattrs
0088             v = attrs.(attrnames{i});
0089             attrvalues{i} = v;
0090         end
0091         DS = dataset_setattribs(DS, nattrs, attrnames, attrvalues);
0092         
0093     case 'attr.list'
0094         len = length(attrs);
0095         if mod(len, 2) ~= 0
0096             error('dsdml:invalidarg', ...
0097                 'The length of the input argument list should be even when it specifies attribute list');
0098         end
0099         nattrs = len / 2;
0100         attrnames = attrs(1:2:end)';
0101         attrvalues = attrs(2:2:end)';
0102         DS = dataset_setattribs(DS, nattrs, attrnames, attrvalues);       
0103         
0104     case 'from:fns'
0105         DS = construct_dataset_filenames(DS, params{:});
0106 end
0107 
0108 
0109 %%  Sub functions
0110 
0111 function DS = dataset_setattribs(DS, n, attrnames, attrvalues)
0112 
0113 % check values
0114 for i = 1 : n
0115     if ~ischar(attrvalues{i})
0116         error('dsdml:invalidarg', ...
0117             'The %d attribute value is not a char string', i);
0118     end
0119 end
0120 
0121 % set values
0122 S = DS;
0123 
0124 for i = 1 : n
0125     aname = attrnames{i};
0126     aval = attrvalues{i};
0127     
0128     if isfield(S, aname)
0129         S.(aname) = aval;
0130     else
0131         S.attribs.(aname) = aval;
0132     end
0133     
0134 end
0135 
0136 DS = S;
0137 
0138

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