RAIphy is a semi-supervised metagenomic fragment classification program. It utilizes the genome signatures to characterize the DNA sequences and taxonomic classification is based on an information theoretic measure referred as Relative Abundance Index (RAI).
A DNA sequence of unknown source is classified and taxonomically labeled based on the phylogenetic profiles of the previously sequenced genomes. The profiles are iteratively updated using the unknown DNA sequences and the classification results. After a few cycles, the metagenome is classified into operational taxonomic units.