Kiss FFT Activity
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Activity for Kiss FFT
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Claudio posted a comment on discussion Open Discussion
I found the solution, here is the explanation : kiss_fft.h ( it only has definitions) kiss_fft.c ( it is the real library with functions, we were missing this file ) it worked fine when compiling : gcc -o example example.c kiss_fft.c -lm Now it works great. Regards, Claudio
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Hello, I wrote a simple code to test kiss_fft : prue_getangulozcPQTHD.c : include "kiss_fft.h" .... kiss_fft_cpx cin[Ntama]; kiss_fft_cpx cout[Ntama]; kiss_fft_cfg kiss_fft_state; kiss_fft_state = kiss_fft_alloc(Ntama,0,0,0); for (i=0;i<Ntama;++i) { cin[i].r = 1; cin[i].i = 0; } kiss_fft(kiss_fft_state,cin,cout); free(kiss_fft_state); .... but I got this error when compiling: prue_getangulozcPQTHD.c:(.text+0x51f): undefined reference to kiss_fft_alloc' prue_getangulozcPQTHD.c:(.text+0x816): undefined...
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Konstantinos Kazatzis posted a comment on discussion Open Discussion
Hello, what is the representation of frequencies in the fftr output? I want to do some operations (average, max, etc.) for a certain frequency range, but i don't know the corresponding frequencies in the fftr output. Is there any document that can help me?
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Peter modified a comment on discussion Open Discussion
Hello. I've fixed a quick test to reveal the issue: #define FIXED_POINT 32 #include "kiss_fft.h" const kiss_fft_cpx in[] = { {0, 0}, {1, 0}, {2, 0}, {3, 0}, {4, 0}, {5, 0}, {6, 0}, {7, 0} }; kiss_fft_cpx out[8]; int main() { int i; kiss_fft_cfg mycfg = kiss_fft_alloc(8, 0, NULL, NULL); kiss_fft(mycfg, in, out); for(i = 0; i < 8; i++) { printf("%d %d\n", out[i].r, out[i].i); } } And upon execution it returns: 28 0 -2147483644 10 -2147483644 4 -2147483644 2 -2147483644 0 -2147483644 -2147483646 -2147483644...
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Hello. I've fixed a quick test to reveal the issue: #define FIXED_POINT 32 #include "kiss_fft.h" const kiss_fft_cpx in[] = { {0, 0}, {1, 0}, {2, 0}, {3, 0}, {4, 0}, {5, 0}, {6, 0}, {7, 0} }; kiss_fft_cpx out[4]; int main() { int i; kiss_fft_cfg mycfg = kiss_fft_alloc(8, 0, NULL, NULL); kiss_fft(mycfg, in, out); for(i = 0; i < 8; i++) { printf("%d %d\n", out[i].r, out[i].i); } } And upon execution it returns: 28 0 -2147483644 10 -2147483644 4 -2147483644 2 -2147483644 0 -2147483644 -2147483646 -2147483644...
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zhaojinrong posted a comment on discussion Help
I see,that's right
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for example, if input is complex value sequence, the complex value sequence length is 4 * 2 * 3 * 5, that is the sequence have 120 complex number, I use "kiss_fft" to compute the DFT, then the output will scale down to 1/120, because "kiss_fft" need to do radix2,radix3,radix4,radix5 computation ,That's right?
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for example, if input is complex value sequence, the complex value sequence length is 4 * 2 * 3 * 5, that is the sequence have 120 complex number, I use "kiss_fft" to compute the DFT, then the output will scale down to 1/120, That's right?
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for example, if input is complex value sequence, the complex value sequence length is 423*5, that is the sequence have 120 complex number, I use "kiss_fft" to compute the DFT, then the output will scale down to 1/120, That's right?
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Then the forward and back FFT output magnitude is smaller than the expected, user is responsible for keeping the output magnitude consistent with expected?
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Mark Borgerding posted a comment on discussion Help
Yes, it is to prevent overflow.
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I have some question about fixed-point kiss_fft's butterfly computation. in "kf_bfly2", input divide by 2 use "C_FIXDIV", in "kf_bfly3", input divide by 3 use "C_FIXDIV", in "kf_bfly4", input divide by 4 use "C_FIXDIV", in "kf_bfly5", input divide by 5 use "C_FIXDIV", in "kiss_fftr" also use "C_FIXDIV",from the point of view of FFT algorithm,it's no use, It seems using "C_FIXDIV" just to prevent overflow. but if the input is Q15, what's the output Q value? the output Q value is consistent with input's?...
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I have some question about fixed version kiss_fft's butterfly computation. in "kf_bfly2", input divide by 2 use "C_FIXDIV", in "kf_bfly3", input divide by 3 use "C_FIXDIV", in "kf_bfly4", input divide by 4 use "C_FIXDIV", in "kf_bfly5", input divide by 5 use "C_FIXDIV", in "kiss_fftr" also use "C_FIXDIV",from the point of view of FFT algorithm,it's no use, It seems using "C_FIXDIV" just to prevent overflow. but if the input is Q15, what's the output Q value? the output Q value is consistent with...
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I have some question about fixed version kiss_fft's butterfly computation. in "kf_bfly2", input divide by 2 use "C_FIXDIV", in "kf_bfly3", input divide by 3 use "C_FIXDIV", in "kf_bfly4", input divide by 4 use "C_FIXDIV", in "kf_bfly5", input divide by 5 use "C_FIXDIV", in "kiss_fftr" also use "C_FIXDIV",from the point of view of FFT algorithm,it's no use, Using "C_FIXDIV" just to prevent overflow? but if the input is Q15, what's the output Q value? the output Q value is consistent with input's?...
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Diego Alejandro Parra Guzman posted a comment on discussion Open Discussion
Thanks for your answer, let me know if ther is a paper or a documentation about kiss_fft...
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Nilay Sheth modified a comment on discussion Help
Hi Mark, This is to notify about the fix on fixed point numbers : I observed that...
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Hi Mark, This is to notify about the fix on fixed point numbers : I observed that...
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Hi Mark, This is to notify about the fix : I observed that when I put a #define nfft...
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Thank you Mark, Does that mean that I should have got the Inverse FFT output ? The...
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The fixed point FFT and IFFT both scale downwards to make overflow impossible.
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It has not been much time after downloading kiss_fft 130, and I compiled on VS2015...
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It has not been much time after downloading kiss_fft 130, and I compiled on VS2015...
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btw .. you can't just "zero some coefficients in the FFT transform" without bad side...
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Yes. It certainly is possible. A search for "fft 2d convolution" brings up several...
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neFAST modified a comment on discussion Help
Hi everyone, I've been using Kiss FFT to filter 1D signals successfully and I have...
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Hi everyone, I've been using Kiss FFT to filter 1D signals successfully and I have...
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Lars Jahr modified a comment on discussion Help
Thanks for the reply. I tried using column major ordering for the matrix as well,...
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Thanks for the reply. I tried using column major ordering for the matrix as well,...
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I don't have the time right now to dig into your code. My first suspicion is the...
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Hi all, I'm trying to use Kiss FFT on some 3D matrices, but my results do not match...
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Hi all, I'm trying to use Kiss FFT on some 3D matrices, but my results do not match...
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dejan posted a comment on discussion Help
Hello, i'm kinda struggling with our friend Fourier, i'm noob when it comest to DSP,...
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I cannot think of any real limitations of KISSFFT in this regard, except perhaps...
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Naveen Francis posted a comment on discussion Help
Hi, Is there any limitation to the KissFFT library when it comes to choosing the...
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Kiss FFT released /OldFiles/kiss_fft_v110.tar.gz
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tantalum modified a comment on discussion Help
hi i am trying to compile a shared library and to include or statically link kiss...
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hi i am trying to compile a shared library and to include or statically link kiss...
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Bob posted a comment on discussion Help
I found the solution forthis problem on my own through experimenting. It is in the...
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I found the mistake on my own through experiments. cx_in must be of the same size...
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My formatting was a bit more understandable but now not that important. So where...
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My formatting was a bit more understandable, so where could be my fault. I thought...
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I suspect you are not initializing all your input. Bob bob90-06@users.sf.net wrote:...
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Hello, I have a problem using Kiss FFT. I made an example programme so i could figure...
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Hello, I have a problem using Kiss FFT. I made an example programme so i could figure...
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Did you look at the derivation pdf available under "files"? I'd say it is pretty...
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DavidB posted a comment on discussion Open Discussion
Hello. I was recently directed to KISSFFT and have spent some time reading about...
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RedHot modified a comment on discussion Help
Hello I'm having problems creating an FFT from my base image. The sample image I'm...
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Hello I'm having problems creating an FFT from my base image. The sample image I'm...
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That sounds really cool. I think Eigen eigen.tuxfamily.org would be a natural place...
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Gaspard Petit posted a comment on discussion Open Discussion
I have modified KissFFT using C++ templates in order to improve performance. By precomputing...
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TheSoundOne posted a comment on discussion Help
It seems so, though I can see no reason why. I do some preprocessing on the audio...
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Perhaps there is a scaling difference between kissfft and Audacity?
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Well, I've written a small test code: #include <iostream> #include "include/kiss_fft/kiss_fft.h"...
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Thanks for a reply, I really didn't expect it to be so quick! cx_out is defined as...
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Thanks for a reply, I really didn't expect it to be so quick! cx_out is defined as...
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Thanks for a reply, I really didn't expect it to be so quick! cx_out is defined as...
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Thanks for a reply, I really didn't expect it to be so quick! cx_out is defined as...
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Are you sure you are using the float version of kissfft? cx_out should be complex,...
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Greethings, and thanks for such a useful library! I'm trying to analyze an audio...
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