34.6 Stopping Parameters

A minimization procedure should stop when one of the following conditions is true:

• A minimum has been found to withoutines-for-complex-data.html#Radix_002d2-FFT-routines-for-complex-data" accesskey="p" rel="previous">Radix-2 FFT routines for complex data, Up: Fast Fourier Transforms   [Index]

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  16.4 Mixed-radix FFT routines for complex data

  This section describes mixed-radix FFT algorithms for complex data. The mixed-radix functions work for FFTs of any length. They are a reimplementation of Paul Swarztrauber’s Fortran FFTPACK library. The theory is explained in the review article Self-sorting Mixed-radix FFTs by Clive Temperton. The routines here use the same indexing scheme and basic algorithms as FFTPACK.

  The mixed-radix algorithm is based on sub-transform modules—highly optimized small length FFTs which are combined to create larger FFTs. There are efficient modules for factors of 2, 3, 4, 5, 6 and 7. The modules for the composite factors of 4 and 6 are faster than combining the modules for 2*2 and 2*3.

  For factors wh