/* * Free FFT and convolution (C++) * * Copyright (c) 2021 Project Nayuki. (MIT License) * https://www.nayuki.io/page/free-small-fft-in-multiple-languages * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of * the Software, and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * - The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * - The Software is provided "as is", without warranty of any kind, express or * implied, including but not limited to the warranties of merchantability, * fitness for a particular purpose and noninfringement. In no event shall the * authors or copyright holders be liable for any claim, damages or other * liability, whether in an action of contract, tort or otherwise, arising from, * out of or in connection with the Software or the use or other dealings in the * Software. */ #pragma once #include #include namespace Fft { /* * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector. * The vector can have any length. This is a wrapper function. The inverse transform does not perform scaling, so it is not a true inverse. */ void transform(std::vector > &vec, bool inverse); /* * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector. * The vector's length must be a power of 2. Uses the Cooley-Tukey decimation-in-time radix-2 algorithm. */ void transformRadix2(std::vector > &vec, bool inverse); /* * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector. * The vector can have any length. This requires the convolution function, which in turn requires the radix-2 FFT function. * Uses Bluestein's chirp z-transform algorithm. */ void transformBluestein(std::vector > &vec, bool inverse); /* * Computes the circular convolution of the given complex vectors. Each vector's length must be the same. */ std::vector > convolve( std::vector > xvec, std::vector > yvec); }