翻译：y = filter(b,a,x,zi) uses initial conditions zi for the filter delays. The length of zi must equal max(length(a),length(b))-1. example y = filter(b,a,x,zi,dim) acts along dimension dim. For example, if x is a matrix, then filter(b,a,x,zi,2) returns the filtered data for each row.

y = filter(b,a,x,zi) 使用初始条件zi作为滤波器延迟。zi的长度必须等于max(length(a),length(b))-1。例如，y = filter(b,a,x,zi,dim) 沿着维度dim进行操作。例如，如果x是一个矩阵，则filter(b,a,x,zi,2)返回每行的滤波数据。