In the formula, A is the supplied m by n weighted matrix of term frequencies in a collection of text where m is the number of unique terms, and n is the number of documents. T is a computed m by r matrix of term vectors where r is the rank of A—a measure of its unique dimensions ≤ min("m,n"). S is a computed r by r diagonal matrix of decreasing singular values, and D is a computed n by r matrix of document vectors.