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reference:ft_datatype_comp [2018/08/23 14:43] (current)
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 +=====  FT_DATATYPE_COMP =====
 +
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_datatype_comp"​.
 +
 +<​html><​pre>​
 +  <a href=/​reference/​ft_datatype_comp><​font color=green>​FT_DATATYPE_COMP</​font></​a>​ describes the FieldTrip MATLAB structure for comp data
 + 
 +  The comp data structure represents time-series channel-level data that has
 +  been decomposed or unmixed from the channel level into its components or
 +  "blind sources",​ for example using ICA (independent component analysis) or
 +  PCA. This data structure is usually generated with the <a href=/​reference/​ft_componentanalysis><​font color=green>​FT_COMPONENTANALYSIS</​font></​a>​
 +  function.
 + 
 +  An example of a decomposed raw data structure with 100 components that resulted from
 +  a 151-channel MEG recording is shown here:
 + 
 +            topo: [151x100 double] ​ the compoment topographies
 +        unmixing: [100x151 double] ​ the compoment unmixing matrix
 +       ​topolabel:​ {151x1 cell}      the channel labels (e.g. '​MRC13'​)
 +           ​label:​ {100x1 cell}      the component labels (e.g. '​runica001'​)
 +            time: {1x10 cell}       the time axis [1*Ntime double] per trial
 +           ​trial:​ {1x10 cell}       the numeric data [151*Ntime double] per trial
 +            grad: [1x1 struct] ​     information about the sensor array (for EEG it is called elec)
 +             cfg: [1x1 struct] ​     the configuration used by the function that generated this data structure
 + 
 +  The only difference to the raw data structure is that the comp structure contains
 +  the additional fields unmixing, topo and topolabel. Besides representing the time
 +  series information as a raw data structure (see <a href=/​reference/​ft_datatype_raw><​font color=green>​FT_DATATYPE_RAW</​font></​a>​),​ it is also
 +  possible for time series information to be represented as timelock or freq
 +  structures (see <a href=/​reference/​ft_datatype_timelock><​font color=green>​FT_DATATYPE_TIMELOCK</​font></​a>​ or <a href=/​reference/​ft_datatype_freq><​font color=green>​FT_DATATYPE_FREQ</​font></​a>​).
 + 
 +  Required fields:
 +    - unmixing, topo, topolabel
 + 
 +  Optional fields:
 +    - cfg, all fields from <a href=/​reference/​ft_datatype_raw><​font color=green>​FT_DATATYPE_RAW</​font></​a>,​ <a href=/​reference/​ft_datatype_timelock><​font color=green>​FT_DATATYPE_TIMELOCK</​font></​a>​ or <a href=/​reference/​ft_datatype_freq><​font color=green>​FT_DATATYPE_FREQ</​font></​a>​
 + 
 +  Historical fields:
 +    - offset, fsample
 + 
 +  Revision history:
 +  (2014) The combination of comp with raw, timelock or freq has been defined explicitly.
 + 
 +  (2011) The unmixing matrix has been added to the component data structure.
 + 
 +  (2003) The initial version was defined
 + 
 +  See also <a href=/​reference/​ft_datatype><​font color=green>​FT_DATATYPE</​font></​a>,​ <a href=/​reference/​ft_datatype_comp><​font color=green>​FT_DATATYPE_COMP</​font></​a>,​ <a href=/​reference/​ft_datatype_dip><​font color=green>​FT_DATATYPE_DIP</​font></​a>,​ <a href=/​reference/​ft_datatype_freq><​font color=green>​FT_DATATYPE_FREQ</​font></​a>,​
 +  <a href=/​reference/​ft_datatype_mvar><​font color=green>​FT_DATATYPE_MVAR</​font></​a>,​ <a href=/​reference/​ft_datatype_raw><​font color=green>​FT_DATATYPE_RAW</​font></​a>,​ <a href=/​reference/​ft_datatype_source><​font color=green>​FT_DATATYPE_SOURCE</​font></​a>,​ <a href=/​reference/​ft_datatype_spike><​font color=green>​FT_DATATYPE_SPIKE</​font></​a>,​
 +  <a href=/​reference/​ft_datatype_timelock><​font color=green>​FT_DATATYPE_TIMELOCK</​font></​a>,​ <a href=/​reference/​ft_datatype_volume><​font color=green>​FT_DATATYPE_VOLUME</​font></​a>​
 +</​pre></​html>​