Transforms and filters are tools for processing and analyzing discrete data, and are commonly used in signal processing applications and computational mathematics. When data is represented as a function of time or space, the Fourier transform decomposes the data into frequency components. Thefft功能使用快速的傅立叶变换算法，该算法与其他直接实现相比降低了其计算成本。有关傅立叶分析的更详细的介绍，请参见Fourier Transforms. Theconv和filterfunctions are also useful tools for modifying the amplitude or phase of input data using a transfer function.