Sparse data set processing

A computer implemented method is provided for processing sparse data. A sparse data set is received. A modified sparse data set is calculated by replacing all nonzero values in the sparse data set with a common positive integer. The modified sparse data set is transposed to create a transposed data set. A covariance matrix is calculated by multiplying the transposed data set by the modified sparse data set. A tree of a predefined depth is generated by assigning columns of the sparse data set to right and left nodes based on co-occurrence with a first anchor column and a second anchor column. The first anchor column and the second anchor column are determined based on the covariance matrix.