Comparing Gk arrays with fixed and variable length reads. Experiments on the sliced Khoisan dataset (150 bp-reads) with Gk arrays (fixed-length reads and variable-length reads). (a) Maximal space consumption of each index for several read numbers and values of k (the error bars represent the variation in space usage, depending on k). (b) Index construction time (the lighter gray corresponds to the smaller k). (c) Query computation time for 13,000,000 reads depending on different k values.