FFT是离散傅里叶变换的快速算法，也可用于计算离散傅里叶变换的逆变换。快速傅里叶变换有广泛的应用，如数字信号处理、计算大整数乘法、求解偏微分方程-The FFT is a fast algorithm, can also be used to calculate the discrete Fourier transform of the inverse transform of the discrete Fourier transform. Fast Fourier Transform of a wide range of applications, such as digital signal processing, to calculate large integer multiplication, solving partial differential equations