config BR2_PACKAGE_FFTW bool "fftw" select BR2_PACKAGE_FFTW_DOUBLE if !BR2_PACKAGE_FFTW_SINGLE \ && !BR2_PACKAGE_FFTW_LONG_DOUBLE && !BR2_PACKAGE_FFTW_QUAD help Library for computing Fast Fourier Transforms. This library computes Fast Fourier Transforms (FFT) in one or more dimensions. It is extremely fast. This package contains the shared library version of the fftw libraries in double precision. http://www.fftw.org if BR2_PACKAGE_FFTW source "package/fftw/fftw-single/Config.in" source "package/fftw/fftw-double/Config.in" source "package/fftw/fftw-long-double/Config.in" source "package/fftw/fftw-quad/Config.in" config BR2_PACKAGE_FFTW_FAST bool "optimise for speed over accuracy" help Optimise for fast math functions, at the expense of accuracy. Say 'y' if you need speed and can live with inaccuracies in the results. Say 'n' (the default) if accuracy is of utmost importance. This basically uses gcc's -Ofast optimisation level, which in turn is basically using gcc's -ffast-math. See the gcc manual for what this means. endif