function A = seq2flat(X)

% A.data is a NN x D matrix
% A.labels is a 1 x NN matrix
% A.origlabels 
% A.comments

A.origlabels = X.origlabels;
A.comments = X.comments;
A.data = [];
A.labels = [];
if isfield(X,'valid');
  A.valid = [];
end
for k=1:length(X.data)
  A.data = vertcat(A.data,X.data{k});
  A.labels = horzcat(A.labels,X.labels{k});
  if isfield(X,'valid');
    A.valid = horzcat(A.valid,X.valid{k});
  end
end