21.01.2015 Views

Notes on Recursive FFT (Fast Fourier Transform) algorithm Fall ...

Notes on Recursive FFT (Fast Fourier Transform) algorithm Fall ...

Notes on Recursive FFT (Fast Fourier Transform) algorithm Fall ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

(10) The pseudocode for <strong>FFT</strong> (recursive versi<strong>on</strong>) from Cormen, Leissers<strong>on</strong>, et al, is:<br />

<strong>FFT</strong> (a) { // 1D array a = (a 0 , a 1 , … , a n-1 )<br />

1 n = length (a) // n is a power of 2<br />

2. if (n == 1)<br />

3. return a<br />

4. ω n = e 2πi/n 1<br />

// ω n<br />

5. ω = 1<br />

6. a [0] = (a 0 , a 2 , a 4 , … a n-2 )<br />

7. a [1] = (a 1 , a 3 , a 5 , … a n-1 )<br />

8. y [0] = <strong>FFT</strong>(a [0] )<br />

9. y [1] = <strong>FFT</strong>(a [1] )<br />

10. for (k=0; k

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!