“…However, spectral clustering is known to suffer from a high computational cost associated with the n × n matrix W , especially when n is large. Consequently, there has been considerable effort to develop fast, approximate algorithms that can handle large data sets (Fowlkes et al, 2004;Yan et al, 2009;Sakai and Imiya, 2009;Wang et al, 2009;Chen and Cai, 2011;Wang et al, 2011;Tasdemir, 2012;Choromanska et al, 2013;Cai and Chen, 2015;Moazzen and Tasdemir, 2016;Chen, 2018). Interestingly, a considerable fraction of them use a landmark set to help reduce the computational complexity of spectral clustering.…”