Well, yes, but it would be a waste of time for both of us:

1. Assign zero to j.

2. Divide n by 2 and assign the result to n2.

And so on. I don't think that's what you were looking for. Could you perhaps produce a more practical question?

Piotr Orzech
Greenhorn

Joined: Sep 13, 2011
Posts: 3

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I've read about fft and i found few steps how to do this. I don't know how to assign them to this code.

1.Prepare input data for summation — put them into convenient order;
2.For every summation level:
2.1For every exponent factor of the half-period:
2.2Calculate factor;
2.1.1For every sum of this factor:
2.1.2Calculate product of the factor and the second term of the sum;
2.1.3Calculate sum;
2.1.4Calculate difference.

What's FFT and DIT? You should always explain abbreviations.

Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 41051

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. . . and welcome to the Ranch

Piotr Orzech
Greenhorn

Joined: Sep 13, 2011
Posts: 3

posted

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FFT - Fast Fourier Transfomate
DIT - Decimation In Time

There is some bit reverse (i dont know how it exacly works) and calculation called butterflies. I am begginer in programming and I need a little patiece :P

Piotr Orzech wrote:I am begginer in programming...

Do you understand the mathematics behind FFT and DIT? That is the hard part here. You need to get good grasp of this first and then to analyze code you didn't even write. Trying to understand the algorithm from a foreign code (possibly optimized using clever mathematical tricks, or - worse - even buggy) when you're a beginner in programming would certainly be a frustrating task.