to ja bede litosciwy, nie taki strasznie zly jak cala reszta i wkleje tobie pierwszy link jaki pokazal sie w google
http://www.cs.princeton.edu/introcs/97data/FFT.java.html
dodatkowo po zrozumienie odsylam do numerical recipes (co prawda w fortran/c/c++/pascal) do rozdzialu 12 Fast Fourier Transform.
BTW
guest79 napisał(a)
Qyon z google korzystac to ja umiem.
Nie potrafisz i to potwierdziles ...
........... i jescze, jakbys twierdzil, ze jest nie dzialajacy:
E:\Program Files\Java\jdk1.5.0_06\bin>javac Complex.java
E:\Program Files\Java\jdk1.5.0_06\bin>javac fft.java
E:\Program Files\Java\jdk1.5.0_06\bin>java FFT 4
x
-------------------
0.09982867282673746
-0.9578212028700461
0.2866509559839743
-0.15875122750287907
y = fft(x)
-------------------
-0.7300928015622135
-0.18682228315723687 + 0.7990699753671671i
1.503052059183637
-0.18682228315723676 - 0.7990699753671671i
z = ifft(y)
-------------------
0.09982867282673746
-0.9578212028700461 - 3.291113424925024E-18i
0.2866509559839743
-0.15875122750287907 + 3.291113424925024E-18i
c = cconvolve(x, x)
-------------------
0.3962451178526821 - 4.163336342344337E-17i
-0.2822484212303113 - 9.141013365362393E-18i
0.9998553779018843 + 4.163336342344337E-17i
-0.5808165756312935 + 9.141013365362393E-18i
d = convolve(x, x)
-------------------
0.00996576391834783 - 4.85722573273506E-17i
-0.19123603897565195 + 4.7471197596623016E-17i
0.9746534256682133 + 1.9503689630166832E-17i
-0.5808165756312935 + 3.232608229831011E-17i
0.3862793539343343 + 6.938893903907228E-18i
-0.09101238225465937 - 5.661221096198541E-17i
0.025201952233670888 + 2.2129673793276538E-17i
-2.3185068932947716E-17i