fftw

问题 I am trying to solve Poison equation with Dirichlet boundary condition for four sides of computational domain. As known that I should use FFTW_RODFT00 to satisfy the condition. However, the result is not correct.Could you please help me? #include <stdio.h> #include <math.h> #include <cmath> #include <fftw3.h> #include <iostream> #include <vector> using namespace std; int main() { int N1=100; int N2=100; double pi = 3.141592653589793; double L1 = 2.0; double dx = L1/(double)(N1-1); double L2=

问题 I'm working with batched 2D FFTs using the FFTW advanced data layout API. According to the FFTW Advanced Complex DFT documentation: Passing NULL for an nembed parameter is equivalent to passing n . However, I'm getting different results when using inembed = onembed = NULL vs. inembed = onembed = n . What could be causing the results not to match? Let's do an example... Setup int howMany = 2; int nRows = 4; int nCols = 4; int n[2] = {nRows, nCols}; float* h_in = (float*)malloc(sizeof(float) *

问题 recently I faced some problems concerning the use of fftw and it's c2c transformation (see: 3d c2c fft with fftw library). As I located my problems in the use of the fftw lib I created a new Question in order to discus this situation in a more concrete way. Since I am doing a complex to complex transform with real data my transformed data in fourier space is supposed to be symmetric: F[n] = con(F[N-n]) Now I did some transformations with small blocks of test-data to check the transformed data

问题 I am having problems getting FFTW 3.3 to work on my system.I downloaded the files from the fftw.org website, and then followed the installation instructions which told me to go to the terminal and type ./Configure make and everything seemed OK, but when I try and use FFTW in my C code by using the include<fft3> statement I get the fatal error fatal error: 'fftw3.h' file not found Does anyone know what I am doing wrong? My IDE: Eclipse, My System: OSX 10.8 回答1: ./configure make make install

问题 I use phase correlation for image stitching and it gives good results for most part of my test data. I just stitiching pairs of image left-right and top-bottom(only shift) But there is some strange behaviour. First strange coordinates, I must convert coordinates //if L-R pt.x= src->width-maxloc.x; pt.y= src->height-maxloc.y; if(pt.y>(temp->height/2)) pt.y= -(maxloc.y+1); //if T-B pt.x= src->width-maxloc.x; pt.y= src->height-maxloc.y; if(pt.x>(temp->width/2)) pt.x= -(maxloc.x+1); Then usage of

问题 I am currently need to run FFT on 1024 sample points signal. So far I have implementing my own DFT algorithm in python, but it is very slow. If I use the NUMPY fftpack, or even move to C++ and use FFTW, do you guys think it would be better? 回答1: If you are implementing the DFFT entirely within Python, your code will run orders of magnitude slower than either package you mentioned. Not just because those libraries are written in much lower-level languages, but also (FFTW in particular) they

问题 I'm trying to use Tamas Szalay's C# port of FFTW in Visual C# 2010, and I'm getting the above error when I try to use a function from FFTW (in this case fftw.malloc). That error goes away if I manually move the dll into the project's /bin/debug/ folder, but then I get An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B) Method: IntPtr malloc(Int32) which makes me think I have a deeper problem. Possibly relevant: I'm running this on an x64

问题 I'm having trouble trying to implement fftw3 with openCV in the same project. I'm new to c/c++ and any help will be much appreciated. The following is just a sample code i used: #include "fftw3.h" #include <stdlib.h> int main(){ fftw_complex *in, *out; fftw_plan p; int N=8; in = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N); out = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * N); p = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE); for(int i=0; i<N; i++){ in[i][0]=i; in

问题 I am trying to cross-compil FFTW 3.3.3 for cortex-a15 ARM processor with neon support but I get this error: /tmp/ccsNpqyK.s: Assembler messages: /tmp/ccsNpqyK.s:1035: Error: co-processor offset out of range Here is my configuration: ./configure --prefix=/usr/fftw_3_float_neon_ARNDALE --with-slow-timer --host=arm-linux-gnueabi --target=arm-linux-gnueabi --enable-float --enable-neon "CC=/usr/bin/arm-linux-gnueabi-gcc-4.6 -mfloat-abi=softfp -mcpu=cortex-a15 -mtune=cortex-a15 -O3 -mfpu=neon

问题 I'm trying to implement the Matlab fft2() function in C using the FFTW3 library. However, I've got different results. Considering the next matrix: Z=[ 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4791 0.4765 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4798 0.4695 0.4791 0