This is a simple Python ctypes-based wrapper around this speedy suffix array construction implementation in C. It also includes an implementation of Kasai's method for constructing the longest common prefix array from a suffix array in linear time.

Building:

cd sais/sais-lite
make dll

Basic Usage:

import sais

seq = sais.Sequence('banana$')

print seq.suffix_array[:len(myseq)]   # -> [6, 5, 3, 1, 0, 4, 2]
print seq.lcp_array[:len(myseq)]      # -> [-1, 0, 1, 3, 0, 0, 2]

def longest_repeated_substring(seq):
    idx, lcp = max(seq.lcp_array[:len(myseq)], key=lambda (_, v): v)
    suffix_start = seq.suffix_array[idx]
    suffix_end = suffix_start + lcp
    return seq.seq[suffix_start:suffix_end]

print longest_repeated_substring(seq)     # -> 'ana'

References:

• Suffix arrays
• Longest common prefix