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Questions tagged [fftpack]

FFTPACK is a package of Fortran subprograms for the fast Fourier transform of periodic and other symmetric sequences. It includes complex, real, sine, cosine, and quarter-wave transforms. Much of the package is also available in a C, Fortran, and Java translation.

FFTPACK is a package of Fortran subprograms for the fast Fourier transform of periodic and other symmetric sequences. It includes complex, real, sine, cosine, and quarter-wave transforms. Much of the package is also available in a C, Fortran, and Java translation.

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How to import a java package in Android Studio

I'm new in android, and I want to import the jfftpack to my project in android studio anda i don't know how to import it. The original code was import ca.uol.aig.realdoublefft and I'don't know where to put the java files. I've tried to put them to…
user3027891
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How to multiply two 2D RFFT arrays (FFTPACK) to be compatible with NumPy's FFT?

I'm trying to multiply two 2D arrays that were transformed with fftpack_rfft2d() (SciPy's FFTPACK RFFT) and the result is not compatible with what I get from scipy_rfft2d() (SciPy's FFT RFFT). The image below shares the output of the script, which…
karlphillip
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How should I multiply scipy.fftpack output vectors together?

The scipy.fftpack.rfft function returns the DFT as a vector of floats, alternating between the real and complex part. This means to multiply to DFTs together (for convolution) I will have to do the complex multiplication "manually" which seems…
Corvus
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Scipy's fftpack dct and idct

Let say you use the dct function, then do no manipulation of the data and use the invert transform; wouldn't the inverted data be the same as the pre-transformed data? Why the floating point issue? Is it a reported issue or is it a normal…
macrocosme
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Basic use of Java fftpack

I've written some simple audio processing algorithms in MATLAB that I will be using for an Android application. I'm having some trouble translating the FFT implementation to Java. I'm trying to use the Java version of fftpack, which is reportedly…
Jayz7522
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FInding fft gives keyerror :'Aligned ' pandas

I have a time series data I am trying to find the fft .But it gives keyerror :Aligned when trying to get the value my data looks like below this is the code: import datetime import numpy as np import scipy as sp import scipy.fftpack import pandas…
Priya
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How do I use inverse FFT from FFTPack?

I'm trying to use FFT from the ANSI C (C89) compatible FFT library FFTPack. So far, I can transform time domin data into frequecy domain data /* Fast Fourier Transform * x[n] - Will contains the FFT values. The first value will have no imaginary…
euraad
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Trouble with Fourier Transform using fftpack5.1

I have an issue using the FFTPACK5.1 in Fortran 90 which contains subroutines to compute discrete Fourier transforms. I manage to install it and use the routines but when I'm checking if everything is ok with a simple sine wave with a frequency A I…
websealevel
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Power spectrum of real data with fftpack on log axis

I already read many discussion about this topic (comparison between lomb-scargle and fft , Plotting power spectrum in python, Scipy/Numpy FFT Frequency Analysis, and many others), but still can't manage it, so I need some tips. I have a list of…
Py-ser
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getting output ifft at a different resolution

I'm trying to smooth and interpolate some periodic data in python using scipy.fftp. I have managed to take the fft of the data, remove the higher order frequencies above wn (by doing myfft[wn:-wn] = 0) and then reconstruct a "smoothed" version of…
nrob
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MKL FFTW is Slower than FFTPACK for small data size

I wrote a matrix computation C++ library 20 years ago and I’m willing to boost its performance using intel MKL library. For complex value vector/matrix, my library uses two split arrays: one for the real part and one for imaginary part. Here are the…
cairdac_rd
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computing dFT at the frequencies of the FFT

I am computing the dFT of a function f(x) sampled at x_i, i=0,1,...,N (with a known dx) at the frequencies u_j, j=0,1,...,N where u_j are frequencies that np.fft.fftfreq(N, dx) generates and compare it with the result of np.fft.fft(f(x)). I find…
Sketos
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Why does running this script freeze my computer?

I wrote a script in Python using SciPy to perform a short-time Fourier transform on a signal. When I ran it on a signal with a thousand timepoints, it ran fine. When I ran it on a signal with a million timepoints, it froze my computer (computer…
BatWannaBe
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Import error for numpy

I downloaded numpy1.8 for python 2.7 Installed fine, but when i give: from numpy.fft import fft, fftfreq it gives me a huge error, which ends with from numpy.core.multiarray import ( ImportError: cannot import name datetime_data How can i get rid…
user3615736
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64-bit SciPy.FFTPack for Windows?

I used to have scipy.fftpack available on 32-bit Python 2.7, but now that I upgraded to 64-bit Python and got SciPy from here, I noticed it doesn't seem to include FFTPack. Where can I download it? Oh, and the error is: >>> import…
user541686
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