Convert a Chebyshev series to a polynomial.
Convert an array representing the coefficients of a Chebyshev series, ordered from lowest degree to highest, to an array of the coefficients of the equivalent polynomial (relative to the “standard” basis) ordered from lowest to highest degree.
- c : array_like
1-D array containing the Chebyshev series coefficients, ordered from lowest order term to highest.
- pol : ndarray
1-D array containing the coefficients of the equivalent polynomial (relative to the “standard” basis) ordered from lowest order term to highest.
The easy way to do conversions between polynomial basis sets is to use the convert method of a class instance.
>>> from numpy import polynomial as P >>> c = P.Chebyshev(range(4)) >>> c Chebyshev([0., 1., 2., 3.], domain=[-1, 1], window=[-1, 1]) >>> p = c.convert(kind=P.Polynomial) >>> p Polynomial([-2., -8., 4., 12.], domain=[-1., 1.], window=[-1., 1.]) >>> P.chebyshev.cheb2poly(range(4)) array([-2., -8., 4., 12.])