Engineering a Lightweight External Memory Suffix Array Construction Algorithm

We describe an external memory su x array construction algorithm based on constructing su x arrays for blocks of text and merging them into the full su x array. The basic idea goes back over 20 years and there has been a couple of later improvements, but we describe several further improvements that make the algorithm much faster. In particular, we reduce the I/O volume of the algorithm by a factor O(log n). Our experiments show that the algorithm is the fastest su x array construction algorithm when the size of the text is within a factor of about five from the size of the RAM in either direction, which is a common situation in practice.