Figure 3.
Global and local basis functions. Global basis functions (e.g., Laguerre basis functions) expand the entire system memory [0, M], while local basis functions (e.g., B-spline basis functions) cover a local region of the system memory. Left panel: Laguerre basis functions (zeroth to 12th order). Right panel: B-spline basis functions (zeroth to 12th order). Top panel: basis functions in 2D color plots (yellow: positive values; blue: negative values; black: zero values). Bottom panel: basis functions in line plots.