fcMRI-VAE / CIFTI_read_save /getdimord_mod.m

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function dimord = getdimord_mod(data, field, varargin)

% GETDIMORD
%
% Use as
%   dimord = getdimord(data, field)
%
% See also GETDIMSIZ, GETDATFIELD

if ~isfield(data, field) && isfield(data, 'avg') && isfield(data.avg, field)
  field = ['avg.' field];
elseif ~isfield(data, field) && isfield(data, 'trial') && isfield(data.trial, field)
  field = ['trial.' field];
elseif ~isfield(data, field)
  error('field "%s" not present in data', field);
end

if strncmp(field, 'avg.', 4)
  prefix = '';
  field = field(5:end); % strip the avg
  data.(field) = data.avg.(field); % copy the avg into the main structure
  data = rmfield(data, 'avg');
elseif strncmp(field, 'trial.', 6)
  prefix = '(rpt)_';
  field = field(7:end); % strip the trial
  data.(field) = data.trial(1).(field); % copy the first trial into the main structure
  data = rmfield(data, 'trial');
else
  prefix = '';
end


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ATTEMPT 1: the specific dimord is simply present
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

if isfield(data, ['dimord'])
  dimord = data.(['dimord']);
  return
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% if not present, we need some additional information about the data strucure
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% nan means that the value is not known and might remain unknown
% inf means that the value is not known but should be known
ntime     = inf;
nfreq     = inf;
nchan     = inf;
nchancmb  = inf;
nsubj     = nan;
nrpt      = nan;
nrpttap   = nan;
npos      = inf;
nori      = nan; % this will be 3 in many cases
ntopochan = inf;
nspike    = inf; % this is only for the first spike channel
nlag      = nan;
ndim1     = nan;
ndim2     = nan;
ndim3     = nan;

% use an anonymous function
assign = @(var, val) assignin('caller', var, val);
% it is possible to pass additional ATTEMPTs such as nrpt, nrpttap, etc
for i=1:2:length(varargin)
  assign(varargin{i}, varargin{i+1});
end

% try to determine the size of each possible dimension in the data
if isfield(data, 'label')
  nchan = length(data.label);
end

if isfield(data, 'labelcmb')
  nchancmb = size(data.labelcmb, 1);
end

if isfield(data, 'time')
  if iscell(data.time) && ~isempty(data.time)
    tmp   = getdimsiz(data, 'time');
    ntime = tmp(3); % raw data may contain variable length trials
  else
    ntime = length(data.time);
  end
end

if isfield(data, 'freq')
  nfreq = length(data.freq);
end

if isfield(data, 'trial') && ft_datatype(data, 'raw')
  nrpt = length(data.trial);
end

if isfield(data, 'trialtime') && ft_datatype(data, 'spike')
  nrpt = size(data.trialtime,1);
end

if isfield(data, 'cumtapcnt')
  nrpt = size(data.cumtapcnt,1);
  if numel(data.cumtapcnt)==length(data.cumtapcnt)
    % it is a vector, hence it only represents repetitions
    nrpttap = sum(data.cumtapcnt);
  else
    % it is a matrix, hence it is repetitions by frequencies
    % this happens after  mtmconvol with keeptrials
    nrpttap = sum(data.cumtapcnt,2);
    if any(nrpttap~=nrpttap(1))
      warning('unexpected variation of the number of tapers over trials')
      nrpttap = nan;
    else
      nrpttap = nrpttap(1);
    end
  end
end

if isfield(data, 'pos')
  npos = size(data.pos,1);
elseif isfield(data, 'dim')
  npos = prod(data.dim);
end

if isfield(data, 'dim')
  ndim1 = data.dim(1);
  ndim2 = data.dim(2);
  ndim3 = data.dim(3);
end

if isfield(data, 'csdlabel')
  % this is used in PCC beamformers
  if length(data.csdlabel)==npos
    % each position has its own labels
    len = cellfun(@numel, data.csdlabel);
    len = len(len~=0);
    if all(len==len(1))
      % they all have the same length
      nori = len(1);
    end
  else
    % one list of labels for all positions
    nori = length(data.csdlabel);
  end
elseif isfinite(npos)
  % assume that there are three dipole orientations per source
  nori = 3;
end

if isfield(data, 'topolabel')
  % this is used in ICA and PCA decompositions
  ntopochan = length(data.topolabel);
end

if isfield(data, 'timestamp') && iscell(data.timestamp)
  nspike = length(data.timestamp{1}); % spike data: only for the first channel
end

if ft_datatype(data, 'mvar') && isfield(data, 'coeffs')
  nlag = size(data.coeffs,3);
end

% determine the size of the actual data
datsiz = getdimsiz(data, field);

tok = {'subj' 'rpt' 'rpttap' 'chan' 'chancmb' 'freq' 'time' 'pos' 'ori' 'topochan' 'lag' 'dim1' 'dim2' 'dim3'};
siz = [nsubj nrpt nrpttap nchan nchancmb nfreq ntime npos nori ntopochan nlag ndim1 ndim2 ndim3];

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ATTEMPT 2: a general dimord is present and might apply
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

if isfield(data, 'dimord')
  dimtok  = tokenize(data.dimord, '_');
  if length(dimtok)>length(datsiz) && check_trailingdimsunitlength(data, dimtok((length(datsiz)+1):end))
    % add the trailing singleton dimensions to datsiz, if needed
    datsiz  = [datsiz ones(1,max(0,length(dimtok)-length(datsiz)))];
  end
  if length(dimtok)==length(datsiz)
    success = false(size(dimtok));
    for i=1:length(dimtok)
      sel = strcmp(tok, dimtok{i});
      if any(sel) && datsiz(i)==siz(sel)
        success(i) = true;
      elseif strcmp(dimtok{i}, 'subj')
        % the number of subjects cannot be determined, and will be indicated as nan
        success(i) = true;
      elseif strcmp(dimtok{i}, 'rpt')
        % the number of trials is hard to determine, and might be indicated as nan
        success(i) = true;
      end
    end % for
    if all(success)
      dimord = data.dimord;
      return
    end
  end
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ATTEMPT 3: look at the size of some common fields that are known
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

switch field
  % the logic for this code is to first check whether the size of a field
  % has an exact match to a potential dimensionality, if not, check for a
  % partial match (ignoring nans)
  
  % note that the case for a cell dimension (typically pos) is handled at
  % the end of this section
  
  case {'pos'}
    if isequalwithoutnans(datsiz, [npos 3])
      dimord = 'pos_unknown';
    end
    
  case {'individual'}
    if isequalwithoutnans(datsiz, [nsubj nchan ntime])
      dimord = 'subj_chan_time';
    end
    
  case {'avg' 'var' 'dof'}
    if isequal(datsiz, [nrpt nchan ntime])
      dimord = 'rpt_chan_time';
    elseif isequal(datsiz, [nchan ntime])
      dimord = 'chan_time';
    elseif isequalwithoutnans(datsiz, [nrpt nchan ntime])
      dimord = 'rpt_chan_time';
    elseif isequalwithoutnans(datsiz, [nchan ntime])
      dimord = 'chan_time';
    end
    
  case {'powspctrm' 'fourierspctrm'}
    if isequal(datsiz, [nrpt nchan nfreq ntime])
      dimord = 'rpt_chan_freq_time';
    elseif isequal(datsiz, [nrpt nchan nfreq])
      dimord = 'rpt_chan_freq';
    elseif isequal(datsiz, [nchan nfreq ntime])
      dimord = 'chan_freq_time';
    elseif isequal(datsiz, [nchan nfreq])
      dimord = 'chan_freq';
    elseif isequalwithoutnans(datsiz, [nrpt nchan nfreq ntime])
      dimord = 'rpt_chan_freq_time';
    elseif isequalwithoutnans(datsiz, [nrpt nchan nfreq])
      dimord = 'rpt_chan_freq';
    elseif isequalwithoutnans(datsiz, [nchan nfreq ntime])
      dimord = 'chan_freq_time';
    elseif isequalwithoutnans(datsiz, [nchan nfreq])
      dimord = 'chan_freq';
    end
    
  case {'crsspctrm' 'cohspctrm'}
    if isequal(datsiz, [nrpt nchancmb nfreq ntime])
      dimord = 'rpt_chancmb_freq_time';
    elseif isequal(datsiz, [nrpt nchancmb nfreq])
      dimord = 'rpt_chancmb_freq';
    elseif isequal(datsiz, [nchancmb nfreq ntime])
      dimord = 'chancmb_freq_time';
    elseif isequal(datsiz, [nchancmb nfreq])
      dimord = 'chancmb_freq';
    elseif isequal(datsiz, [nrpt nchan nchan nfreq ntime])
      dimord = 'rpt_chan_chan_freq_time';
    elseif isequal(datsiz, [nrpt nchan nchan nfreq])
      dimord = 'rpt_chan_chan_freq';
    elseif isequal(datsiz, [nchan nchan nfreq ntime])
      dimord = 'chan_chan_freq_time';
    elseif isequal(datsiz, [nchan nchan nfreq])
      dimord = 'chan_chan_freq';
    elseif isequal(datsiz, [npos nori])
      dimord = 'pos_ori';
    elseif isequal(datsiz, [npos 1])
      dimord = 'pos';
    elseif isequalwithoutnans(datsiz, [nrpt nchancmb nfreq ntime])
      dimord = 'rpt_chancmb_freq_time';
    elseif isequalwithoutnans(datsiz, [nrpt nchancmb nfreq])
      dimord = 'rpt_chancmb_freq';
    elseif isequalwithoutnans(datsiz, [nchancmb nfreq ntime])
      dimord = 'chancmb_freq_time';
    elseif isequalwithoutnans(datsiz, [nchancmb nfreq])
      dimord = 'chancmb_freq';
    elseif isequalwithoutnans(datsiz, [nrpt nchan nchan nfreq ntime])
      dimord = 'rpt_chan_chan_freq_time';
    elseif isequalwithoutnans(datsiz, [nrpt nchan nchan nfreq])
      dimord = 'rpt_chan_chan_freq';
    elseif isequalwithoutnans(datsiz, [nchan nchan nfreq ntime])
      dimord = 'chan_chan_freq_time';
    elseif isequalwithoutnans(datsiz, [nchan nchan nfreq])
      dimord = 'chan_chan_freq';
    elseif isequalwithoutnans(datsiz, [npos nori])
      dimord = 'pos_ori';
    elseif isequalwithoutnans(datsiz, [npos 1])
      dimord = 'pos';
    end
    
  case {'cov' 'coh' 'csd' 'noisecov' 'noisecsd'}
    % these occur in timelock and in source structures
    if isequal(datsiz, [nrpt nchan nchan])
      dimord = 'rpt_chan_chan';
    elseif isequal(datsiz, [nchan nchan])
      dimord = 'chan_chan';
    elseif isequal(datsiz, [npos nori nori])
      dimord = 'pos_ori_ori';
    elseif isequal(datsiz, [npos nrpt nori nori])
      dimord = 'pos_rpt_ori_ori';
    elseif isequalwithoutnans(datsiz, [nrpt nchan nchan])
      dimord = 'rpt_chan_chan';
    elseif isequalwithoutnans(datsiz, [nchan nchan])
      dimord = 'chan_chan';
    elseif isequalwithoutnans(datsiz, [npos nori nori])
      dimord = 'pos_ori_ori';
    elseif isequalwithoutnans(datsiz, [npos nrpt nori nori])
      dimord = 'pos_rpt_ori_ori';
    end
    
  case {'pow'}
    if isequal(datsiz, [npos ntime])
      dimord = 'pos_time';
    elseif isequal(datsiz, [npos nfreq])
      dimord = 'pos_freq';
    elseif isequal(datsiz, [npos nrpt])
      dimord = 'pos_rpt';
    elseif isequal(datsiz, [nrpt npos ntime])
      dimord = 'rpt_pos_time';
    elseif isequal(datsiz, [nrpt npos nfreq])
      dimord = 'rpt_pos_freq';
    elseif isequal(datsiz, [npos 1]) % in case there are no repetitions
      dimord = 'pos';
    elseif isequalwithoutnans(datsiz, [npos ntime])
      dimord = 'pos_time';
    elseif isequalwithoutnans(datsiz, [npos nfreq])
      dimord = 'pos_freq';
    elseif isequalwithoutnans(datsiz, [npos nrpt])
      dimord = 'pos_rpt';
    elseif isequalwithoutnans(datsiz, [nrpt npos ntime])
      dimord = 'rpt_pos_time';
    elseif isequalwithoutnans(datsiz, [nrpt npos nfreq])
      dimord = 'rpt_pos_freq';
    end
    
  case {'mom'}
    if isequal(datsiz, [npos nori nrpt])
      dimord = 'pos_ori_rpt';
    elseif isequal(datsiz, [npos nori ntime])
      dimord = 'pos_ori_time';
    elseif isequal(datsiz, [npos nori nfreq])
      dimord = 'pos_ori_nfreq';
    elseif isequal(datsiz, [npos ntime])
      dimord = 'pos_time';
    elseif isequal(datsiz, [npos nfreq])
      dimord = 'pos_freq';
    elseif isequal(datsiz, [npos 3])
      dimord = 'pos_ori';
    elseif isequal(datsiz, [npos 1])
      dimord = 'pos';
    elseif isequal(datsiz, [npos nrpt])
      dimord = 'pos_rpt';
    elseif isequalwithoutnans(datsiz, [npos nori nrpt])
      dimord = 'pos_ori_rpt';
    elseif isequalwithoutnans(datsiz, [npos nori ntime])
      dimord = 'pos_ori_time';
    elseif isequalwithoutnans(datsiz, [npos nori nfreq])
      dimord = 'pos_ori_nfreq';
    elseif isequalwithoutnans(datsiz, [npos ntime])
      dimord = 'pos_time';
    elseif isequalwithoutnans(datsiz, [npos nfreq])
      dimord = 'pos_freq';
    elseif isequalwithoutnans(datsiz, [npos 3])
      dimord = 'pos_ori';
    elseif isequalwithoutnans(datsiz, [npos 1])
      dimord = 'pos';
    elseif isequalwithoutnans(datsiz, [npos nrpt])
      dimord = 'pos_rpt';
    end
    
  case {'filter'}
    if isequalwithoutnans(datsiz, [npos nori nchan]) || (isequal(datsiz([1 2]), [npos nori]) && isinf(nchan))
      dimord = 'pos_ori_chan';
    end
    
  case {'leadfield'}
    if isequalwithoutnans(datsiz, [npos nchan nori]) || (isequal(datsiz([1 3]), [npos nori]) && isinf(nchan))
      dimord = 'pos_chan_ori';
    end
    
  case {'ori' 'eta'}
    if isequal(datsiz, [npos nori]) || isequal(datsiz, [npos 3])
      dimord = 'pos_ori';
    end
    
  case {'csdlabel'}
    if isequal(datsiz, [npos nori]) || isequal(datsiz, [npos 3])
      dimord = 'pos_ori';
    end
    
  case {'trial'}
    if ~iscell(data.(field)) && isequalwithoutnans(datsiz, [nrpt nchan ntime])
      dimord = 'rpt_chan_time';
    elseif isequalwithoutnans(datsiz, [nrpt nchan ntime])
      dimord = '{rpt}_chan_time';
    elseif isequalwithoutnans(datsiz, [nchan nspike]) || isequalwithoutnans(datsiz, [nchan 1 nspike])
      dimord = '{chan}_spike';
    end
    
  case {'sampleinfo' 'trialinfo' 'trialtime'}
    if isequalwithoutnans(datsiz, [nrpt nan])
      dimord = 'rpt_other';
    end
    
  case {'cumtapcnt' 'cumsumcnt'}
    if isequalwithoutnans(datsiz, [nrpt nan])
      dimord = 'rpt_other';
    end
    
  case {'topo'}
    if isequalwithoutnans(datsiz, [ntopochan nchan])
      dimord = 'topochan_chan';
    end
    
  case {'unmixing'}
    if isequalwithoutnans(datsiz, [nchan ntopochan])
      dimord = 'chan_topochan';
    end
    
  case {'inside'}
    if isequalwithoutnans(datsiz, [npos])
      dimord = 'pos';
    end
    
  case {'timestamp' 'time'}
    if ft_datatype(data, 'spike') && iscell(data.(field)) && datsiz(1)==nchan
      dimord = '{chan}_spike';
    elseif ft_datatype(data, 'raw') && iscell(data.(field)) && datsiz(1)==nrpt
      dimord = '{rpt}_time';
    elseif isvector(data.(field)) && isequal(datsiz, [1 ntime ones(1,numel(datsiz)-2)])
      dimord = 'time';
    end
    
  case {'freq'}
    if isvector(data.(field)) && isequal(datsiz, [1 nfreq])
      dimord = 'freq';
    end
    
  otherwise
    if isfield(data, 'dim') && isequal(datsiz, data.dim)
      dimord = 'dim1_dim2_dim3';
    end
    
end % switch field

% deal with possible first pos which is a cell
if exist('dimord', 'var') && strcmp(dimord(1:3), 'pos') && iscell(data.(field))
  dimord = ['{pos}' dimord(4:end)];
end

if ~exist('dimord', 'var')
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % ATTEMPT 4: there is only one way that the dimensions can be interpreted
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  dimtok = cell(size(datsiz));
  
  for i=1:length(datsiz)
    sel = find(siz==datsiz(i));
    if length(sel)==1
      % there is exactly one corresponding dimension
      dimtok{i} = tok{sel};
    else
      % there are zero or multiple corresponding dimensions
      dimtok{i} = [];
    end
  end
  
  if all(~cellfun(@isempty, dimtok))
    if iscell(data.(field))
      dimtok{1} = ['{' dimtok{1} '}'];
    end
    dimord = sprintf('%s_', dimtok{:});
    dimord = dimord(1:end-1);
    return
  end
end % if dimord does not exist

if ~exist('dimord', 'var')
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % ATTEMPT 5: compare the size with the known size of each dimension
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  sel = ~isnan(siz) & ~isinf(siz);
  % nan means that the value is not known and might remain unknown
  % inf means that the value is not known and but should be known
  if length(unique(siz(sel)))==length(siz(sel))
    % this should only be done if there is no chance of confusing dimensions
    dimtok = cell(size(datsiz));
    dimtok(datsiz==npos)      = {'pos'};
    dimtok(datsiz==nori)      = {'ori'};
    dimtok(datsiz==nrpttap)   = {'rpttap'};
    dimtok(datsiz==nrpt)      = {'rpt'};
    dimtok(datsiz==nsubj)     = {'subj'};
    dimtok(datsiz==nchancmb)  = {'chancmb'};
    dimtok(datsiz==nchan)     = {'chan'};
    dimtok(datsiz==nfreq)     = {'freq'};
    dimtok(datsiz==ntime)     = {'time'};
    dimtok(datsiz==ndim1)     = {'dim1'};
    dimtok(datsiz==ndim2)     = {'dim2'};
    dimtok(datsiz==ndim3)     = {'dim3'};
    
    if isempty(dimtok{end}) && datsiz(end)==1
      % remove the unknown trailing singleton dimension
      dimtok = dimtok(1:end-1);
    elseif isequal(dimtok{1}, 'pos') && isempty(dimtok{2}) && datsiz(2)==1
      % remove the unknown leading singleton dimension
      dimtok(2) = [];
    end
    
    if all(~cellfun(@isempty, dimtok))
      if iscell(data.(field))
        dimtok{1} = ['{' dimtok{1} '}'];
      end
      dimord = sprintf('%s_', dimtok{:});
      dimord = dimord(1:end-1);
      return
    end
  end
end % if dimord does not exist

if ~exist('dimord', 'var')
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % ATTEMPT 6: check whether it is a 3-D volume
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  if isequal(datsiz, [ndim1 ndim2 ndim3])
    dimord = 'dim1_dim2_dim3';
  end
end % if dimord does not exist

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% FINAL RESORT: return "unknown" for all unknown dimensions
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if ~exist('dimord', 'var')
  % this should not happen
  % if it does, it might help in diagnosis to have a very informative warning message
  % since there have been problems with trials not being selected correctly due to the warning going unnoticed
  % it is better to throw an error than a warning
  warning('could not determine dimord of "%s" in the following data', field)
  disp(data);
  
  dimtok(cellfun(@isempty, dimtok)) = {'unknown'};
  if all(~cellfun(@isempty, dimtok))
    if iscell(data.(field))
      dimtok{1} = ['{' dimtok{1} '}'];
    end
    dimord = sprintf('%s_', dimtok{:});
    dimord = dimord(1:end-1);
  end
end

% add '(rpt)' in case of source.trial
dimord = [prefix dimord];


end % function

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SUBFUNCTION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function ok = isequalwithoutnans(a, b)

% this is *only* used to compare matrix sizes, so we can ignore any singleton last dimension
numdiff = numel(b)-numel(a);

if numdiff > 0
  % assume singleton dimensions missing in a
  a = [a(:); ones(numdiff, 1)];
  b = b(:);
elseif numdiff < 0
  % assume singleton dimensions missing in b
  b = [b(:); ones(abs(numdiff), 1)];
  a = a(:);
end

c = ~isnan(a(:)) & ~isnan(b(:));
ok = isequal(a(c), b(c));

end % function isequalwithoutnans

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SUBFUNCTION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function ok = check_trailingdimsunitlength(data, dimtok)

ok = false;
for k = 1:numel(dimtok)
  switch dimtok{k}
    case 'chan'
      ok = numel(data.label)==1;
    otherwise
      if isfield(data, dimtok{k}); % check whether field exists
        ok = numel(data.(dimtok{k}))==1;
      end;
  end
  if ok,
    break;
  end
end

end % function check_trailingdimsunitlength

	function dimord = getdimord_mod(data, field, varargin)

	% GETDIMORD
	%
	% Use as
	% dimord = getdimord(data, field)
	%
	% See also GETDIMSIZ, GETDATFIELD

	if ~isfield(data, field) && isfield(data, 'avg') && isfield(data.avg, field)
	field = ['avg.' field];
	elseif ~isfield(data, field) && isfield(data, 'trial') && isfield(data.trial, field)
	field = ['trial.' field];
	elseif ~isfield(data, field)
	error('field "%s" not present in data', field);
	end

	if strncmp(field, 'avg.', 4)
	prefix = '';
	field = field(5:end); % strip the avg
	data.(field) = data.avg.(field); % copy the avg into the main structure
	data = rmfield(data, 'avg');
	elseif strncmp(field, 'trial.', 6)
	prefix = '(rpt)_';
	field = field(7:end); % strip the trial
	data.(field) = data.trial(1).(field); % copy the first trial into the main structure
	data = rmfield(data, 'trial');
	else
	prefix = '';
	end


	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 1: the specific dimord is simply present
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	if isfield(data, ['dimord'])
	dimord = data.(['dimord']);
	return
	end

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% if not present, we need some additional information about the data strucure
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	% nan means that the value is not known and might remain unknown
	% inf means that the value is not known but should be known
	ntime = inf;
	nfreq = inf;
	nchan = inf;
	nchancmb = inf;
	nsubj = nan;
	nrpt = nan;
	nrpttap = nan;
	npos = inf;
	nori = nan; % this will be 3 in many cases
	ntopochan = inf;
	nspike = inf; % this is only for the first spike channel
	nlag = nan;
	ndim1 = nan;
	ndim2 = nan;
	ndim3 = nan;

	% use an anonymous function
	assign = @(var, val) assignin('caller', var, val);
	% it is possible to pass additional ATTEMPTs such as nrpt, nrpttap, etc
	for i=1:2:length(varargin)
	assign(varargin{i}, varargin{i+1});
	end

	% try to determine the size of each possible dimension in the data
	if isfield(data, 'label')
	nchan = length(data.label);
	end

	if isfield(data, 'labelcmb')
	nchancmb = size(data.labelcmb, 1);
	end

	if isfield(data, 'time')
	if iscell(data.time) && ~isempty(data.time)
	tmp = getdimsiz(data, 'time');
	ntime = tmp(3); % raw data may contain variable length trials
	else
	ntime = length(data.time);
	end
	end

	if isfield(data, 'freq')
	nfreq = length(data.freq);
	end

	if isfield(data, 'trial') && ft_datatype(data, 'raw')
	nrpt = length(data.trial);
	end

	if isfield(data, 'trialtime') && ft_datatype(data, 'spike')
	nrpt = size(data.trialtime,1);
	end

	if isfield(data, 'cumtapcnt')
	nrpt = size(data.cumtapcnt,1);
	if numel(data.cumtapcnt)==length(data.cumtapcnt)
	% it is a vector, hence it only represents repetitions
	nrpttap = sum(data.cumtapcnt);
	else
	% it is a matrix, hence it is repetitions by frequencies
	% this happens after mtmconvol with keeptrials
	nrpttap = sum(data.cumtapcnt,2);
	if any(nrpttap~=nrpttap(1))
	warning('unexpected variation of the number of tapers over trials')
	nrpttap = nan;
	else
	nrpttap = nrpttap(1);
	end
	end
	end

	if isfield(data, 'pos')
	npos = size(data.pos,1);
	elseif isfield(data, 'dim')
	npos = prod(data.dim);
	end

	if isfield(data, 'dim')
	ndim1 = data.dim(1);
	ndim2 = data.dim(2);
	ndim3 = data.dim(3);
	end

	if isfield(data, 'csdlabel')
	% this is used in PCC beamformers
	if length(data.csdlabel)==npos
	% each position has its own labels
	len = cellfun(@numel, data.csdlabel);
	len = len(len~=0);
	if all(len==len(1))
	% they all have the same length
	nori = len(1);
	end
	else
	% one list of labels for all positions
	nori = length(data.csdlabel);
	end
	elseif isfinite(npos)
	% assume that there are three dipole orientations per source
	nori = 3;
	end

	if isfield(data, 'topolabel')
	% this is used in ICA and PCA decompositions
	ntopochan = length(data.topolabel);
	end

	if isfield(data, 'timestamp') && iscell(data.timestamp)
	nspike = length(data.timestamp{1}); % spike data: only for the first channel
	end

	if ft_datatype(data, 'mvar') && isfield(data, 'coeffs')
	nlag = size(data.coeffs,3);
	end

	% determine the size of the actual data
	datsiz = getdimsiz(data, field);

	tok = {'subj' 'rpt' 'rpttap' 'chan' 'chancmb' 'freq' 'time' 'pos' 'ori' 'topochan' 'lag' 'dim1' 'dim2' 'dim3'};
	siz = [nsubj nrpt nrpttap nchan nchancmb nfreq ntime npos nori ntopochan nlag ndim1 ndim2 ndim3];

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 2: a general dimord is present and might apply
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	if isfield(data, 'dimord')
	dimtok = tokenize(data.dimord, '_');
	if length(dimtok)>length(datsiz) && check_trailingdimsunitlength(data, dimtok((length(datsiz)+1):end))
	% add the trailing singleton dimensions to datsiz, if needed
	datsiz = [datsiz ones(1,max(0,length(dimtok)-length(datsiz)))];
	end
	if length(dimtok)==length(datsiz)
	success = false(size(dimtok));
	for i=1:length(dimtok)
	sel = strcmp(tok, dimtok{i});
	if any(sel) && datsiz(i)==siz(sel)
	success(i) = true;
	elseif strcmp(dimtok{i}, 'subj')
	% the number of subjects cannot be determined, and will be indicated as nan
	success(i) = true;
	elseif strcmp(dimtok{i}, 'rpt')
	% the number of trials is hard to determine, and might be indicated as nan
	success(i) = true;
	end
	end % for
	if all(success)
	dimord = data.dimord;
	return
	end
	end
	end

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 3: look at the size of some common fields that are known
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	switch field
	% the logic for this code is to first check whether the size of a field
	% has an exact match to a potential dimensionality, if not, check for a
	% partial match (ignoring nans)

	% note that the case for a cell dimension (typically pos) is handled at
	% the end of this section

	case {'pos'}
	if isequalwithoutnans(datsiz, [npos 3])
	dimord = 'pos_unknown';
	end

	case {'individual'}
	if isequalwithoutnans(datsiz, [nsubj nchan ntime])
	dimord = 'subj_chan_time';
	end

	case {'avg' 'var' 'dof'}
	if isequal(datsiz, [nrpt nchan ntime])
	dimord = 'rpt_chan_time';
	elseif isequal(datsiz, [nchan ntime])
	dimord = 'chan_time';
	elseif isequalwithoutnans(datsiz, [nrpt nchan ntime])
	dimord = 'rpt_chan_time';
	elseif isequalwithoutnans(datsiz, [nchan ntime])
	dimord = 'chan_time';
	end

	case {'powspctrm' 'fourierspctrm'}
	if isequal(datsiz, [nrpt nchan nfreq ntime])
	dimord = 'rpt_chan_freq_time';
	elseif isequal(datsiz, [nrpt nchan nfreq])
	dimord = 'rpt_chan_freq';
	elseif isequal(datsiz, [nchan nfreq ntime])
	dimord = 'chan_freq_time';
	elseif isequal(datsiz, [nchan nfreq])
	dimord = 'chan_freq';
	elseif isequalwithoutnans(datsiz, [nrpt nchan nfreq ntime])
	dimord = 'rpt_chan_freq_time';
	elseif isequalwithoutnans(datsiz, [nrpt nchan nfreq])
	dimord = 'rpt_chan_freq';
	elseif isequalwithoutnans(datsiz, [nchan nfreq ntime])
	dimord = 'chan_freq_time';
	elseif isequalwithoutnans(datsiz, [nchan nfreq])
	dimord = 'chan_freq';
	end

	case {'crsspctrm' 'cohspctrm'}
	if isequal(datsiz, [nrpt nchancmb nfreq ntime])
	dimord = 'rpt_chancmb_freq_time';
	elseif isequal(datsiz, [nrpt nchancmb nfreq])
	dimord = 'rpt_chancmb_freq';
	elseif isequal(datsiz, [nchancmb nfreq ntime])
	dimord = 'chancmb_freq_time';
	elseif isequal(datsiz, [nchancmb nfreq])
	dimord = 'chancmb_freq';
	elseif isequal(datsiz, [nrpt nchan nchan nfreq ntime])
	dimord = 'rpt_chan_chan_freq_time';
	elseif isequal(datsiz, [nrpt nchan nchan nfreq])
	dimord = 'rpt_chan_chan_freq';
	elseif isequal(datsiz, [nchan nchan nfreq ntime])
	dimord = 'chan_chan_freq_time';
	elseif isequal(datsiz, [nchan nchan nfreq])
	dimord = 'chan_chan_freq';
	elseif isequal(datsiz, [npos nori])
	dimord = 'pos_ori';
	elseif isequal(datsiz, [npos 1])
	dimord = 'pos';
	elseif isequalwithoutnans(datsiz, [nrpt nchancmb nfreq ntime])
	dimord = 'rpt_chancmb_freq_time';
	elseif isequalwithoutnans(datsiz, [nrpt nchancmb nfreq])
	dimord = 'rpt_chancmb_freq';
	elseif isequalwithoutnans(datsiz, [nchancmb nfreq ntime])
	dimord = 'chancmb_freq_time';
	elseif isequalwithoutnans(datsiz, [nchancmb nfreq])
	dimord = 'chancmb_freq';
	elseif isequalwithoutnans(datsiz, [nrpt nchan nchan nfreq ntime])
	dimord = 'rpt_chan_chan_freq_time';
	elseif isequalwithoutnans(datsiz, [nrpt nchan nchan nfreq])
	dimord = 'rpt_chan_chan_freq';
	elseif isequalwithoutnans(datsiz, [nchan nchan nfreq ntime])
	dimord = 'chan_chan_freq_time';
	elseif isequalwithoutnans(datsiz, [nchan nchan nfreq])
	dimord = 'chan_chan_freq';
	elseif isequalwithoutnans(datsiz, [npos nori])
	dimord = 'pos_ori';
	elseif isequalwithoutnans(datsiz, [npos 1])
	dimord = 'pos';
	end

	case {'cov' 'coh' 'csd' 'noisecov' 'noisecsd'}
	% these occur in timelock and in source structures
	if isequal(datsiz, [nrpt nchan nchan])
	dimord = 'rpt_chan_chan';
	elseif isequal(datsiz, [nchan nchan])
	dimord = 'chan_chan';
	elseif isequal(datsiz, [npos nori nori])
	dimord = 'pos_ori_ori';
	elseif isequal(datsiz, [npos nrpt nori nori])
	dimord = 'pos_rpt_ori_ori';
	elseif isequalwithoutnans(datsiz, [nrpt nchan nchan])
	dimord = 'rpt_chan_chan';
	elseif isequalwithoutnans(datsiz, [nchan nchan])
	dimord = 'chan_chan';
	elseif isequalwithoutnans(datsiz, [npos nori nori])
	dimord = 'pos_ori_ori';
	elseif isequalwithoutnans(datsiz, [npos nrpt nori nori])
	dimord = 'pos_rpt_ori_ori';
	end

	case {'pow'}
	if isequal(datsiz, [npos ntime])
	dimord = 'pos_time';
	elseif isequal(datsiz, [npos nfreq])
	dimord = 'pos_freq';
	elseif isequal(datsiz, [npos nrpt])
	dimord = 'pos_rpt';
	elseif isequal(datsiz, [nrpt npos ntime])
	dimord = 'rpt_pos_time';
	elseif isequal(datsiz, [nrpt npos nfreq])
	dimord = 'rpt_pos_freq';
	elseif isequal(datsiz, [npos 1]) % in case there are no repetitions
	dimord = 'pos';
	elseif isequalwithoutnans(datsiz, [npos ntime])
	dimord = 'pos_time';
	elseif isequalwithoutnans(datsiz, [npos nfreq])
	dimord = 'pos_freq';
	elseif isequalwithoutnans(datsiz, [npos nrpt])
	dimord = 'pos_rpt';
	elseif isequalwithoutnans(datsiz, [nrpt npos ntime])
	dimord = 'rpt_pos_time';
	elseif isequalwithoutnans(datsiz, [nrpt npos nfreq])
	dimord = 'rpt_pos_freq';
	end

	case {'mom'}
	if isequal(datsiz, [npos nori nrpt])
	dimord = 'pos_ori_rpt';
	elseif isequal(datsiz, [npos nori ntime])
	dimord = 'pos_ori_time';
	elseif isequal(datsiz, [npos nori nfreq])
	dimord = 'pos_ori_nfreq';
	elseif isequal(datsiz, [npos ntime])
	dimord = 'pos_time';
	elseif isequal(datsiz, [npos nfreq])
	dimord = 'pos_freq';
	elseif isequal(datsiz, [npos 3])
	dimord = 'pos_ori';
	elseif isequal(datsiz, [npos 1])
	dimord = 'pos';
	elseif isequal(datsiz, [npos nrpt])
	dimord = 'pos_rpt';
	elseif isequalwithoutnans(datsiz, [npos nori nrpt])
	dimord = 'pos_ori_rpt';
	elseif isequalwithoutnans(datsiz, [npos nori ntime])
	dimord = 'pos_ori_time';
	elseif isequalwithoutnans(datsiz, [npos nori nfreq])
	dimord = 'pos_ori_nfreq';
	elseif isequalwithoutnans(datsiz, [npos ntime])
	dimord = 'pos_time';
	elseif isequalwithoutnans(datsiz, [npos nfreq])
	dimord = 'pos_freq';
	elseif isequalwithoutnans(datsiz, [npos 3])
	dimord = 'pos_ori';
	elseif isequalwithoutnans(datsiz, [npos 1])
	dimord = 'pos';
	elseif isequalwithoutnans(datsiz, [npos nrpt])
	dimord = 'pos_rpt';
	end

	case {'filter'}
	if isequalwithoutnans(datsiz, [npos nori nchan]) \|\| (isequal(datsiz([1 2]), [npos nori]) && isinf(nchan))
	dimord = 'pos_ori_chan';
	end

	case {'leadfield'}
	if isequalwithoutnans(datsiz, [npos nchan nori]) \|\| (isequal(datsiz([1 3]), [npos nori]) && isinf(nchan))
	dimord = 'pos_chan_ori';
	end

	case {'ori' 'eta'}
	if isequal(datsiz, [npos nori]) \|\| isequal(datsiz, [npos 3])
	dimord = 'pos_ori';
	end

	case {'csdlabel'}
	if isequal(datsiz, [npos nori]) \|\| isequal(datsiz, [npos 3])
	dimord = 'pos_ori';
	end

	case {'trial'}
	if ~iscell(data.(field)) && isequalwithoutnans(datsiz, [nrpt nchan ntime])
	dimord = 'rpt_chan_time';
	elseif isequalwithoutnans(datsiz, [nrpt nchan ntime])
	dimord = '{rpt}_chan_time';
	elseif isequalwithoutnans(datsiz, [nchan nspike]) \|\| isequalwithoutnans(datsiz, [nchan 1 nspike])
	dimord = '{chan}_spike';
	end

	case {'sampleinfo' 'trialinfo' 'trialtime'}
	if isequalwithoutnans(datsiz, [nrpt nan])
	dimord = 'rpt_other';
	end

	case {'cumtapcnt' 'cumsumcnt'}
	if isequalwithoutnans(datsiz, [nrpt nan])
	dimord = 'rpt_other';
	end

	case {'topo'}
	if isequalwithoutnans(datsiz, [ntopochan nchan])
	dimord = 'topochan_chan';
	end

	case {'unmixing'}
	if isequalwithoutnans(datsiz, [nchan ntopochan])
	dimord = 'chan_topochan';
	end

	case {'inside'}
	if isequalwithoutnans(datsiz, [npos])
	dimord = 'pos';
	end

	case {'timestamp' 'time'}
	if ft_datatype(data, 'spike') && iscell(data.(field)) && datsiz(1)==nchan
	dimord = '{chan}_spike';
	elseif ft_datatype(data, 'raw') && iscell(data.(field)) && datsiz(1)==nrpt
	dimord = '{rpt}_time';
	elseif isvector(data.(field)) && isequal(datsiz, [1 ntime ones(1,numel(datsiz)-2)])
	dimord = 'time';
	end

	case {'freq'}
	if isvector(data.(field)) && isequal(datsiz, [1 nfreq])
	dimord = 'freq';
	end

	otherwise
	if isfield(data, 'dim') && isequal(datsiz, data.dim)
	dimord = 'dim1_dim2_dim3';
	end

	end % switch field

	% deal with possible first pos which is a cell
	if exist('dimord', 'var') && strcmp(dimord(1:3), 'pos') && iscell(data.(field))
	dimord = ['{pos}' dimord(4:end)];
	end

	if ~exist('dimord', 'var')
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 4: there is only one way that the dimensions can be interpreted
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	dimtok = cell(size(datsiz));

	for i=1:length(datsiz)
	sel = find(siz==datsiz(i));
	if length(sel)==1
	% there is exactly one corresponding dimension
	dimtok{i} = tok{sel};
	else
	% there are zero or multiple corresponding dimensions
	dimtok{i} = [];
	end
	end

	if all(~cellfun(@isempty, dimtok))
	if iscell(data.(field))
	dimtok{1} = ['{' dimtok{1} '}'];
	end
	dimord = sprintf('%s_', dimtok{:});
	dimord = dimord(1:end-1);
	return
	end
	end % if dimord does not exist

	if ~exist('dimord', 'var')
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 5: compare the size with the known size of each dimension
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	sel = ~isnan(siz) & ~isinf(siz);
	% nan means that the value is not known and might remain unknown
	% inf means that the value is not known and but should be known
	if length(unique(siz(sel)))==length(siz(sel))
	% this should only be done if there is no chance of confusing dimensions
	dimtok = cell(size(datsiz));
	dimtok(datsiz==npos) = {'pos'};
	dimtok(datsiz==nori) = {'ori'};
	dimtok(datsiz==nrpttap) = {'rpttap'};
	dimtok(datsiz==nrpt) = {'rpt'};
	dimtok(datsiz==nsubj) = {'subj'};
	dimtok(datsiz==nchancmb) = {'chancmb'};
	dimtok(datsiz==nchan) = {'chan'};
	dimtok(datsiz==nfreq) = {'freq'};
	dimtok(datsiz==ntime) = {'time'};
	dimtok(datsiz==ndim1) = {'dim1'};
	dimtok(datsiz==ndim2) = {'dim2'};
	dimtok(datsiz==ndim3) = {'dim3'};

	if isempty(dimtok{end}) && datsiz(end)==1
	% remove the unknown trailing singleton dimension
	dimtok = dimtok(1:end-1);
	elseif isequal(dimtok{1}, 'pos') && isempty(dimtok{2}) && datsiz(2)==1
	% remove the unknown leading singleton dimension
	dimtok(2) = [];
	end

	if all(~cellfun(@isempty, dimtok))
	if iscell(data.(field))
	dimtok{1} = ['{' dimtok{1} '}'];
	end
	dimord = sprintf('%s_', dimtok{:});
	dimord = dimord(1:end-1);
	return
	end
	end
	end % if dimord does not exist

	if ~exist('dimord', 'var')
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% ATTEMPT 6: check whether it is a 3-D volume
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	if isequal(datsiz, [ndim1 ndim2 ndim3])
	dimord = 'dim1_dim2_dim3';
	end
	end % if dimord does not exist

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% FINAL RESORT: return "unknown" for all unknown dimensions
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	if ~exist('dimord', 'var')
	% this should not happen
	% if it does, it might help in diagnosis to have a very informative warning message
	% since there have been problems with trials not being selected correctly due to the warning going unnoticed
	% it is better to throw an error than a warning
	warning('could not determine dimord of "%s" in the following data', field)
	disp(data);

	dimtok(cellfun(@isempty, dimtok)) = {'unknown'};
	if all(~cellfun(@isempty, dimtok))
	if iscell(data.(field))
	dimtok{1} = ['{' dimtok{1} '}'];
	end
	dimord = sprintf('%s_', dimtok{:});
	dimord = dimord(1:end-1);
	end
	end

	% add '(rpt)' in case of source.trial
	dimord = [prefix dimord];


	end % function

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% SUBFUNCTION
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	function ok = isequalwithoutnans(a, b)

	% this is only used to compare matrix sizes, so we can ignore any singleton last dimension
	numdiff = numel(b)-numel(a);

	if numdiff > 0
	% assume singleton dimensions missing in a
	a = [a(:); ones(numdiff, 1)];
	b = b(:);
	elseif numdiff < 0
	% assume singleton dimensions missing in b
	b = [b(:); ones(abs(numdiff), 1)];
	a = a(:);
	end

	c = ~isnan(a(:)) & ~isnan(b(:));
	ok = isequal(a(c), b(c));

	end % function isequalwithoutnans

	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	% SUBFUNCTION
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	function ok = check_trailingdimsunitlength(data, dimtok)

	ok = false;
	for k = 1:numel(dimtok)
	switch dimtok{k}
	case 'chan'
	ok = numel(data.label)==1;
	otherwise
	if isfield(data, dimtok{k}); % check whether field exists
	ok = numel(data.(dimtok{k}))==1;
	end;
	end
	if ok,
	break;
	end
	end

	end % function check_trailingdimsunitlength