Effect of thresholds Lr and Ls.

The memory usage means the summation of byte allocation to store intermediate data to calculate next decomposition results (e.g. auxiliary matrices G and H). We use Korea Air Quality dataset with rank 20, and change Lr and Ls to investigate the effect of refinement and split processes. Note that the lower the thresholds is set, the more frequently the re-decomposition processes are executed. Thus, one can benefit from this observation when there is a particular importance in one of accuracy, speed, or memory usage depending on target tasks.