“…For example, in the field of pattern recognition, the mean shift algorithm (Fukunaga & Hostetler, 1975) is one of the most popular methods for density-based clustering, which is nothing but the multiple mode estimation method (Cheng, 1995). Regression toward the mode (Lee, 1989;Kemp & Silva, 2012) has been attracting the interest of many statisticians and is an active area of research (Yao & Li, 2014;Ota, Kato, & Hara, 2019;Sando, Akaho, Murata, & Hino, 2019). Chacón (2020) provided a recent comprehensive review on the use of mode, and our work provides a novel example of the use of the mode for PCA.…”