On Sun, Jul 24, 2011 at 5:10 PM, Robert Elsner <[email protected]> wrote:
> Boiled it down a bit more to only include code that actually takes time.
> First time around I found the other variant more instructive because it
> shows the discrepancy between the DCT and the loop but might be
> confusing. Thus here the bare minimum that correctly calculates the
> coefficients of the first derivative from the coefficients of the
> Chebyshev polynomials.
>
>
Have you tried using an (inverse) discrete sine transform to get the
derivative? dT_n/dx = n*U_{n-1}, where U_n is the Chebyshev polynomial of
the second kind, sin((n+1)\theta)/sin(theta) where cos(\theta) = x. I don't
believe the discrete sine transform is part of scipy, but you can just use
the inverse fft instead.
<snip>
Chuck
_______________________________________________
NumPy-Discussion mailing list
[email protected]
http://mail.scipy.org/mailman/listinfo/numpy-discussion
