c++ - FFTW3 DFT 2D always return NaN -

i'm trying dft real 2d matrix using fftw3. code snippet:

size_t nyh = ny/2 + 1; out = (fftw_complex*)fftw_malloc ( sizeof ( fftw_complex ) * nx * nyh );  plan_forward = fftw_plan_dft_r2c_2d ( nx, ny, in, out, fftw_estimate );  fftw_execute ( plan_forward ); 

where in double* each value @ order of e-270.

my problem out contains -nan values.

is there trick correct values?

thank you

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thank everybody.

the problem running in not due fftw3 library , code correct despite of it's weakness.

my problem came input feed fftw_plan_dft_r2c_2d function issued cv::mat image. so, post error did getting trouble:)

i convert cv::mat vector<vector<double> > using function:

static matrixofdouble _convertmat( cv::mat& inmat) {     matrixofdouble result;      (int = 0; < inmat.rows; ++i)     {         std::vector<double> row;         (int j = 0; j < inmat.cols; ++j)         {             row.push_back(inmat.at<double>(i, j));         }         result.push_back(row);     }      return result; } 

and liniarize returned matrix feed dft function.

but of result matrix elements nan.

as fix, cv::mat element long instead of double:

row.push_back(inmat.at<long>(i, j)); 

good luck trying solve issue.