https://docs.scipy.org/doc/scipy/reference/interpolate.html#module-scipy.interpolate
https://stackoverflow.com/questions/31464345/fitting-a-closed-curve-to-a-set-of-points
包含样条函数和类，一维和多维（单变量和多变量）插值类，拉格朗日和泰勒多项式插值器，以及FITPACK 和DFITPACK函数的封装。
Univariate interpolation
scipy.interpolate.interp1d
class scipy.interpolate.interp1d（x，y，kind ='linear'，axis = -1，copy = True，bounds_error = None，fill_value = nan，assume_sorted = False ）
scipy.interpolate.BarycentricInterpolator
class scipy.interpolate.BarycentricInterpolator（xi，yi = None，axis = 0 ）
样条：
scipy.interpolate.splprep
scipy.interpolate.splprep(x, w=None, u=None, ub=None, ue=None, k=3, task=0, s=None, t=None, full_output=0, nest=None, per=0, quiet=1)
Find the B-spline representation of an N-dimensional curve.
Given a list of N rank-1 arrays, x, which represent a curve in N-dimensional space parametrized by u, find a smooth approximating spline curve g(u). Uses the FORTRAN routine parcur from FITPACK.