# Questions tagged [fast-fourier-transform]

Use this tag for questions related to the fast Fourier transform, an algorithm that samples a signal over a period of time (or space) and divides it into its frequency components.

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### iFFT a Known Transformed Function to Get the Unknown Complex-valued Initial Function

Background: In my case, I need to get the solution of a series of 2D equations. The analytical expression of this solution ($f$) is not available but the transformed one is. Therefore, I need to ...
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### Given Green's function, can I find the corresponding operator?

Green's function is the solution to the equation $L G(x;x') = \delta(x-x')$, where $L$ is a linear differential operator. Usually, we want to find the Green's function of a given $L$. Instead, if we ...
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### Frequency ranges of the even and odd term of DFT while developing a FFT algorithm

I'm reading this book: "Theory and application of digital signal processing" by Lawrence R. Rabiner and Bernard Gold. During the development of the classical matrix refactorization used to ...
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### Obtaining weights numerically via a Fourier Transform

I have a particularly nasty function, f(x), and I want to numerically find the values $g_k$ where they are defined as the following. $f(x) = \sum^{\infty}_{k=-\infty}g_k \text{exp}(ikx)$ I want to ...
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