CTDT: CTD Transition (CTDT)
In ftrCOOL: Feature Extraction from Biological Sequences

Description Usage Arguments Value References Examples

This function computes the transition part of CTD. Thirteen properties are defined in this function. Each property categorizes the amino acids of a sequence into three groups. For each property, the grouped amino acid transition (i.e., transitions 1-2, 1-3, and 2-3) is calculated. For more information, please check the references.

1	CTDT(seqs, normalized = FALSE, label = c())

`seqs`	is a FASTA file with amino acid sequences. Each sequence starts with a '>' character. Also, seqs could be a string vector. Each element of the vector is a peptide/protein sequence.
`normalized`	is a logical parameter. When it is FALSE, the return value of the function does not change. Otherwise, the return value is normalized using the length of the sequence.
`label`	is an optional parameter. It is a vector whose length is equivalent to the number of sequences. It shows the class of each entry (i.e., sequence).

This function returns a feature matrix. The number of rows is equal to the number of sequences and the number of columns is 3*7, where three is the number of transition types (i.e., 1-2, 1-3, and 2-3) and thirteen is the number of properties.

Dubchak, Inna, et al. "Prediction of protein folding class using global description of amino acid sequence." Proceedings of the National Academy of Sciences 92.19 (1995): 8700-8704.