- Matrix Format: Each row represents a separate sequence.
- Cell Array Format: Each cell contains a sequence vector.
- https://www.mathworks.com/help/stats/hmmtrain.html
- https://www.mathworks.com/matlabcentral/answers/51238-hmmtrain-m-with-unknown-state-sequence-baum-welch?s_tid=answers_rc1-2_p2_MLT