cl-fftw » Overview

cl-fftw is a wrapper around FFTW library (in double and single precision). There are two types of functions: for use with plans and "fast" ones which are prefixed with % and do not require manual plan creation.

This is a list of FFT functions which work with plans:

1. fft does a complex-to-complex transform (in both directions).
2. rfft does a transform of real-valued input.
3. irfft is an inverse of rfft.

Plans for these functions can be created as follows:

1. create-fft-plan for fft.
2. create-rfft-plan for rfft.
3. create-irfft-plan for irfft.

A plan must be destroyed with destroy-plan when it is no longer needed. A convenient macro with-plan helps to control lifetime of a plan.

There are two packages: cl-fftw/double and cl-fftw/single which have the same set of functions but work with different precision. Two commonly used constants, +forward+ and +backward+ which are used to specify the transform's direction are in cl-fftw/core package.