FFTW, "The Fastest Fourier Transform in The West", is a C library which implements discrete Fourier Transforms. It is licensed under the GNU GPL.
FFTW homepage: http://www.fftw.org/
FAQ: http://www.fftw.org/faq/
Questions tagged [fftw]
883 questions
4
votes
2 answers
How do you use the batch mode of CUFFT?
I am trying to figure out how to use the batch mode offered in the CUFFT library.
I basically have an image that is 5300 pixels wide and 3500 tall. Currently this means I am running 3500 1D FFT's on those 5300 elements using FFTW.
Is this a good…
Derek
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4
votes
2 answers
Where can I find a good source of information that explains FFT phase correlation scoring
I've been looking to the OpenCV's magnificent source code to understand the score calculation. As you may have noticed the library can find a template in an image with a confidence score. cvMatchTemplate function gives the probability and location…
Celal Ergün
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4
votes
1 answer
Oscillation and frequency spectrum through a Fourier transform
I'm trying to find the oscillation and spectrum frequency of the waveform generated by a vector of data representing the motion of a pixel in an image.
The data is stored in a .txt file, as follows:
75.000000
60.000000
52.000000
61.000000…
Jorge Cruz
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4
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c++ Using C99 complex with FFTW in C++14
I'm having trouble using the C99 complex data type with FFTW and C++14.
// fftw14.cc
#include
#include
int main() {
fftw_complex* in;
in = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * 100);
in[0] =…
murphy
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4
votes
1 answer
c++ use 1D Array with 2D Data
I do not use any matrix library, but instead plain std::vector for my matrix data.
To fill it with 2D data I use this code:
data[iy + dataPointsY * ix] = value;
I would like to know is this is correct or if it must be the other way (ix first).
To…
Matthias Pospiech
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4
votes
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Is FFTW significantly better than GSL for real transform calculations?
I'm unable to get FFTW to link to my code in order to use its functions in my code. I have spent enough time on this that I am considering giving up on it.
I am very familiar with GSL, and have used the linear algebra libraries extensively with good…
Machinus
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votes
0 answers
Select axes DFT of multi-dimensional array (using FFTW)
I have data that is ordered as follows
[ z, y, x, i, j ]
where [z,y,x] represent physical dimensions and [i,j] represent tensor dimensions. I.e. it stores a second-order tensor at points in grid with shape [z,y,x].
I would like to calculate the…
Tom de Geus
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Can I use MKL and FFTW in the same program?
I'm currently writing a program that requires both MKL and FFTW.
The FFTW plan function I need is "fftw_plan_r2r_2d," which according the material I found, is not yet available in MKL, and the wrapper from MKL will always return a NULL pointer.
This…
Roger Lee
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4
votes
2 answers
Length of FFT and IFFT
I have some signals which I add up to a larger signal, where each signal is located in a different frequency region.
Now, I perform the FFT operation on the big signal with FFTW and cut the concrete FFT bins (where the signals are located) out.
For…
mbed_dev
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4
votes
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Strange behaviour of fftw_mpi_plan_dft_r2c_3d
It seems that the runtime behaviour of fftw_mpi_plan_dft_r2c_3d is strongly affect by the first three arguments it takes. The following code is almosted copied from the fftw doc. By setting L to 512 and running 48 processes, it gives segmentation…
user4286578
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4
votes
1 answer
How do I get a .so file from a .la file?
FFTW 2.x builds a .la file (under fftw/.libs directory).
I think I need a .so file to link to. (I am not sure, because I am a gcc newbie).
Ries
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4
votes
1 answer
How to do a fftw3 MPI "transposed" 2D transform if possible at all?
Consider a 2D transform of the form L x M (column major setup), from a complex array src to a real array tgt. Or , in Fortranese,
complex(C_DOUBLE_COMPLEX), pointer :: src(:,:)
real(8), pointer :: tgt(:,:) .
Corresponding pointers are
type(C_PTR)…
Mali Remorker
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4
votes
1 answer
Install fftw-2.1.5 with mpi in local
I'm trying to install fftw-2.1.5 libraries on a IBM cluster with linux, with the --enable-mpi flag, but I have since failed to do so.
I need fftw version 2.1.5 because GADGET2 code requires that version, with mpi support.
First, I installed…
gbaso
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4
votes
3 answers
FFTW on Mac OS X Mavericks issues
I am sure this is a simple issue, but I am having a rough time getting in done. I am using this code snippet from http://www.fftw.org/fftw2_doc/fftw_2.html. I have the library installed (via homebrew). The include folder (/usr/local/include) has…
Red
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4
votes
1 answer
Replacing numpy.fft routines with pyfftw, not working as expected
I have some working python code making use of the numpy.fft package, here is a snippet:
for i in range(steps):
print i
psixvec = Ux * psixvec
psikvec = Uk * np.fft.fftn(psixvec)
psixvec = np.fft.ifftn(psikvec)
return psixvec
I…
Micha
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