hurst指数估计
　This function does dispersional analysis on a data series, then does a
　Matlab polyfit to a log-log plot to estimate the Hurst exponent of the
　series.

　This algorithm is far faster than a full-blown implementation of Hurst s
　algorithm.　I got the idea from a 2000 PhD dissertation by Hendrik J
　Blok, and I make no guarantees whatsoever about the rigor of this approach
　or the accuracy of results.　Use it at your own risk.
,hurst
　This function does dispersional analysis on a data series, then does a
　Matlab polyfit to a log-log plot to estimate the Hurst exponent of the
　series.

　This algorithm is far faster than a full-blown implementation of Hurst s
　algorithm.　I got the idea from a 2000 PhD dissertation by Hendrik J
　Blok, and I make no guarantees whatsoever about the rigor of this approach
　or the accuracy of results.　Use it at your own risk.