VQ

说明：  LBG算法设计矢量量化码书的函数，需要给出训练序列x,矢量维数K和码书长度CN，返回根据训练序列给出的最小误差码书。(LBG algorithm for vector quantization codebook design function , you need to give training sequence x, vector dimension K and codebook length CN, return according to the minimum error given training sequence codebook . )