说明：  三角平滑去噪算法，矩形平滑去噪算法，伪高斯平滑去噪算法的实现
(fastbsmooth(Y,w,type,ends) smooths vector Y with smooth of width w. Version 2.0, May 2008. The argument type determines the smooth type: If type 1, rectangular (sliding-average or boxcar) If type 2, triangular (2 passes of sliding-average) If type 3, pseudo-Gaussian (3 passes of sliding-average) The argument ends controls how the ends of the signal (the first w/2 points and the last w/2 points) are handled. If ends 0, the ends are zero. (In this mode the elapsed time is independent of the smooth width). The fastest. If ends 1, the ends are smoothed with progressively smaller smooths the closer to the end. (In this mode the elapsed time increases with increasing smooth widths). fastsmooth(Y,w,type) smooths with ends 0. fastsmooth(Y,w) smooths with type 1 and ends 0.)