gcant / dct-cpp

Discrete cosine transforms et al. in C++ (wrapper for FFTW).

dct-cpp

Discrete cosine transforms et al. in C++ (wrapper for FFTW). Requires fftw3. Tested for std::vector<double>, Eigen::VectorXd and Eigen::ArrayXd.

Compile the example with

g++ example.cpp -std=c++11 -O3 -lfftw3

From the FFTW documentation:

• FFTW_R2HC computes a real-input DFT with output in “halfcomplex” format (inverse is FFTW_HC2R)
• FFTW_HC2R computes the reverse of FFTW_R2HC, above (inverse is FFTW_R2HC)
• FFTW_DHT computes a discrete Hartley transform (inverse is FFTW_DHT)
• FFTW_REDFT00 computes a DCT-I (inverse is FFTW_REDFT00.)
• FFTW_REDFT10 computes a DCT-II, sometimes called “the” DCT (inverse is FFTW_REDFT01)
• FFTW_REDFT01 computes a DCT-III, sometimes called “the” IDCT, being the inverse of DCT-II (inverse is FFTW_REDFT=10)
• FFTW_REDFT11 computes a DCT-IV (inverse is FFTW_REDFT11)
• FFTW_RODFT00 computes a DST-I (inverse is FFTW_RODFT00)
• FFTW_RODFT10 computes a DST-II (inverse is FFTW_RODFT01)
• FFTW_RODFT01 computes a DST-III (inverse is FFTW_RODFT10)
• FFTW_RODFT11 computes a DST-IV (inverse is FFTW_RODFT11)