0,default, just using the complete transcript sequences;
1, optional, using the subsequences specified by the index (e.g. >id start_pos end_pos);
2, optional, spliting the transcript into fragments, please provides the window size (-w, defualt 174) and the step size (-s, defualt 50);

Ignore this option if the selected model is not 2.

Ignore this option if the selected model is not 2.