Re: fft from numerical recipes

Arantxa wrote:
It seems you have found the answer to your problem. And I would like to
know it. I have visited the page you recommend, but I have seen nothing
new. My case is a little bit different, because I am using the three
dimensional version, but I think your explanation would be useful for me.
Another question, how do you introduce the data of the negative
coordinates? Maybe my questions are stupid, but , please, help Arantxa

You wrap them around. So if your data is:

{{-3, 3}, {-2, 2}, {-1, 1}, {0, 0}, {1, 1}, {2, 2}, {3, 3}}

then you rotate it until t=0 is the first element:

{{0, 0}, {1, 1}, {2, 2}, {3, 3}, {-3, 3}, {-2, 2}, {-1, 1}}

and then apply the FFT to the second elements:

{0, 1, 2, 3, 3, 2, 1}

--
Dr Jon D Harrop, Flying Frog Consultancy
The F#.NET Journal
http://www.ffconsultancy.com/products/fsharp_journal/?usenet
.