Re: [eigen] uniform spaced cpx sinusoid via rootfinding, was Re: FFT module thoughts

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Mark, thank you for explaining your ideas. I think it might be a great way to avoid exp() computing (prone to cancellation errors).
Need to study this further, thank you for the Matlab script!

On Fri, Apr 6, 2012 at 12:55 AM, Mark Borgerding <mark@xxxxxxxxxxxxxx> wrote:
To create a root-finder, I'd probably start by trying to use  There might be a more suitable algorithm for finding complex roots of unity.

One could use this root-finder to create an entire cycle via the algorithm in the attached octave/matlab script.
The idea is similar to

The only reason I can think of not to do this for the general case is fear of worst-case numerical performance (e.g. n is a large prime).  One thought: This  might be mitigated by comparing the complex sinusoid with its time-reversed and conjugated self.

On 04/05/2012 11:02 AM, Pavel Holoborodko wrote:
Hi Mark.
I would really appreciate if you would provide some links on how to re-write make_twiddles using root finding approach.

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