fftpack

How should I multiply scipy.fftpack output vectors together?

由 佐手、 提交于 2020-06-12 06:24:37
问题 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 quite tricky. This must be something people do often - I presume/hope there is a simple trick to do this efficiently that I haven't spotted? Basically I want to fix this code so that both methods give the same answer: import numpy as np import scipy

How to multiply two 2D RFFT arrays (FFTPACK) to be compatible with NumPy's FFT?

由 被刻印的时光 ゝ 提交于 2020-05-20 05:05:50
问题 This bounty has ended . Answers to this question are eligible for a +250 reputation bounty. Bounty grace period ends in 23 hours . karlphillip is looking for a canonical answer : Detailed explanation and source code for a function that performs the correct multiplication of two 2D arrays transformed with FFTPACK RFFT. The validation procedure is already embedded in the code of the question: one simply needs to replace the line that says # this doesn't work with the function call that performs

Scipy's fftpack dct and idct

由 北慕城南 提交于 2019-12-10 15:34:35
问题 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 behavior? In [21]: a = [1.2, 3.4, 5.1, 2.3, 4.5] In [22]: b = dct(a) In [23]: b Out[23]: array([ 33. , -4.98384545, -4.5 , -5.971707 , 4.5 ]) In [24]: c = idct(b) In [25]: c Out[25]: array([ 12., 34., 51., 23., 45.]) Anyone has an explanation as why? Of

How to import a java package in Android Studio

由 五迷三道 提交于 2019-12-06 19:00:08
问题 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 a libs folder. here's the jfftpack source code: 回答1: If it's an existing code library, I'd recommend adding a module for it. Probably the easiest way is to use the File menu command to add a new module, let it create a plain Java (non-Android)

How to import a java package in Android Studio

由 只愿长相守 提交于 2019-12-05 00:37:00
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 a libs folder. here's the jfftpack source code: If it's an existing code library, I'd recommend adding a module for it. Probably the easiest way is to use the File menu command to add a new module, let it create a plain Java (non-Android) module for you, remove the sample class it puts into the module, and then copy your files over into it and tweak
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