Is there any simple C++ example on how to use Intel MKL FFT? -

i need perform fft , inverse-fft transformations. input vector , matrices of double. ideally, output should array of std::complex can live double _complex.

i haven't found simple example, intel examples doing lot of things @ once without enough comments.

i want simple example in c++ taking vector (or matrix) of double input , outputting fft-transformed result (ideally std::complex).

i ended testing several things , ended 3 functions want , considered simple examples.

i tested against inputs , had results. haven't done extensive testing though.

//note after each operation status should 0 on success   std::vector<std::complex<float>> fft_complex(std::vector<std::complex<float>>& in){     std::vector<std::complex<float>> out(in.size());      dfti_descriptor_handle descriptor;     mkl_long status;      status = dfticreatedescriptor(&descriptor, dfti_single, dfti_complex, 1, in.size()); //specify size , precision     status = dftisetvalue(descriptor, dfti_placement, dfti_not_inplace); //out of place fft     status = dfticommitdescriptor(descriptor); //finalize descriptor     status = dfticomputeforward(descriptor, in.data(), out.data()); //compute forward fft     status = dftifreedescriptor(&descriptor); //free descriptor      return out; }  std::vector<std::complex<float>> fft_real(std::vector<float>& in_real){     std::vector<std::complex<float>> in(in_real.size());      std::copy(in_real.begin(), in_real.end(), in.begin());      return fft_complex(in); }  std::vector<float> ifft(std::vector<std::complex<float>>& in){     std::vector<std::complex<float>> out(in.size());      dfti_descriptor_handle descriptor;     mkl_long status;      status = dfticreatedescriptor(&descriptor, dfti_single, dfti_complex, 1, in.size()); //specify size , precision     status = dftisetvalue(descriptor, dfti_placement, dfti_not_inplace); //out of place fft     status = dftisetvalue(descriptor, dfti_backward_scale, 1.0f / in.size()); //scale down output     status = dfticommitdescriptor(descriptor); //finalize descriptor     status = dfticomputebackward(descriptor, in.data(), out.data()); //compute forward fft     status = dftifreedescriptor(&descriptor); //free descriptor      std::vector<float> output(out.size());      for(std::size_t = 0; < out.size(); ++i){         output[i] = out[i].real();     }      return output; }