richardson

代码说明：

  A generalized Richardson extrapolation routine that can perform multiple extrapolation steps, can accommodate arbitrary leading error terms, can handle any uniform refinement scheme (e.g. h/2, h/3, h/5, etc), and can report a full extrapolation table including comparing against a known good solution. Able to handle vector inputs. Compatible both with MATLAB and Octave. Includes Octave-style unit tests.