Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_checkdata”.

  FT_CHECKDATA checks the input data of the main FieldTrip functions, e.g. whether the
  type of data strucure corresponds with the required data. If neccessary and possible,
  this function will adjust the data structure to the input requirements (e.g. change
  dimord, average over trials, convert inside from index into logical).
  If the input data does NOT correspond to the requirements, this function will give a
  warning message and if applicable point the user to external documentation (link to
  Use as
    [data] = ft_checkdata(data, ...)
  Optional input arguments should be specified as key-value pairs and can include
    feedback           = yes, no
    datatype           = raw, freq, timelock, comp, spike, source, mesh, dip, volume, segmentation, parcellation
    dimord             = any combination of time, freq, chan, refchan, rpt, subj, chancmb, rpttap, pos
    senstype           = ctf151, ctf275, ctf151_planar, ctf275_planar, neuromag122, neuromag306, bti148, bti248, bti248_planar, magnetometer, electrode
    inside             = logical, index
    ismeg              = yes, no
    iseeg              = yes, no
    isnirs             = yes, no
    hasunit            = yes, no
    hascoordsys        = yes, no
    hassampleinfo      = yes, no, ifmakessense (applies to raw and timelock data)
    hascumtapcnt       = yes, no (only applies to freq data)
    hasdim             = yes, no
    hasdof             = yes, no
    cmbrepresentation  = sparse, full (applies to covariance and cross-spectral density)
    fsample            = sampling frequency to use to go from SPIKE to RAW representation
    segmentationstyle  = indexed, probabilistic (only applies to segmentation)
    parcellationstyle  = indexed, probabilistic (only applies to parcellation)
    hasbrain           = yes, no (only applies to segmentation)
    trialinfostyle     = matrix, table or empty
  For some options you can specify multiple values, e.g.
    [data] = ft_checkdata(data, 'senstype', {'ctf151', 'ctf275'}), e.g. in megrealign
    [data] = ft_checkdata(data, 'datatype', {'timelock', 'freq'}), e.g. in sourceanalysis
  See also FT_DATATYPE_XXX for each of the respective data types.