任何人都可以告诉我切比雪夫在numpy-
之间的区别numpy.polynomial.Chebyshev.basis(deg)
和Chebyshev的scipy解释 -
scipy.special.chebyt(deg)
这将是非常有帮助的。 提前谢谢!
答案 0 :(得分:4)
scipy.special
多项式函数使用np.poly1d
,which is outdated and error prone - 特别是,它将x0
的索引存储在poly.coeffs[-1]
numpy.polynomial.Chebyshev
不仅以更合理的顺序存储系数,而且根据其基础保存系数,从而提高精度。您可以使用cast
方法进行转换:
>>> from numpy.polynomial import Chebyshev, Polynomial
# note loss of precision
>>> sc_che = scipy.special.chebyt(4); sc_che
poly1d([ 8.000000e+00, 0.000000e+00, -8.000000e+00, 8.881784e-16, 1.000000e+00])
# using the numpy functions - note that the result is just in terms of basis 4
>>> np_che = Chebyshev.basis(4); np_che
Chebyshev([ 0., 0., 0., 0., 1.], [-1., 1.], [-1., 1.])
# converting to a standard polynomial - note that these store the
# coefficient of x^i in .coeffs[i] - so are reversed when compared to above
>>> Polynomial.cast(np_che)
Polynomial([ 1., 0., -8., 0., 8.], [-1., 1.], [-1., 1.])