CODEWITHSUNDEEP
c++fftwcimg
arc_lupus
arc_lupus

Reputation: 4114

Combination of CImg and fftw++ fails

I want to do a fft in my c++ project, and show it afterwards as an image. In order to do the fft, I am using fftw++, and for displaying the image I wanted to use the CImg-library. Thus I started with the demo project from here. When compiling it, everything works. As soon as I add the CImg-header, it fails with the error 

test.cpp: In function ‘int main()’:
test.cpp:18:12: error: ‘f’ was not declared in this scope
   Complex *f=ComplexAlign(n);

My file looks like

#include "fftw++.h"
#include "CImg.h"
// Compile with:
// g++ -I .. -fopenmp example0.cc ../fftw++.cc -lfftw3 -lfftw3_omp

//using namespace std;
//using namespace utils;
//using namespace fftwpp;
//using namespace cimg_library;
int main()
{
  fftwpp::fftw::maxthreads=get_max_threads();

  std::cout << "1D complex to complex in-place FFT, not using the Array class"
       << std::endl;

  unsigned int n=4;
  Complex *f=utils::ComplexAlign(n);

  fftwpp::fft1d Forward(n,-1);
  fftwpp::fft1d Backward(n,1);

  for(unsigned int i=0; i < n; i++) f[i]=i;

  std::cout << "\ninput:" << std::endl;
  for(unsigned int i=0; i < n; i++) std::cout << f[i] << std::endl;

  Forward.fft(f);

  std::cout << "\noutput:" << std::endl;
  for(unsigned int i=0; i < n; i++) std::cout << f[i] << std::endl;

  Backward.fftNormalized(f);

  std::cout << "\ntransformed back:" << std::endl;
  for(unsigned int i=0; i < n; i++) std::cout << f[i] << std::endl;

  utils::deleteAlign(f);
}

and is compiled with

g++ -I .. -fopenmp test.cpp ../fftw++.cc -lfftw3 -lfftw3_omp

My g++ version is 4.8.5. Adding the Complex.h-header does not help either. What can I do in order to combine both libraries?

Edit: Further research shows that using the C-library complex.h and CImg.h results in a lot of compilation problems, combining the library Complex.h from the fftw++-package results also in errors, only the complex-include from C++ can be used together with the CImg.h-include file. Reason: Unknown till now.

Upvotes: 1

Views: 256

Answers (1)

arc_lupus
arc_lupus

Reputation: 4114

My solution (even if it is not perfect) is, that I created a second cpp-file:
second.cpp:

#include "CImg.h"
//Code for images
void example(void){
}

and an include-file for that:
second.h:

#ifndef SECOND_H
#define SECOND_H

void example(void);


#endif /* SECOND_H */

If I only include that include file instead of CImg.h, I can use both fftw++ and CImg.

Upvotes: 1

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