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%FFTW Interface to FFTW library run-time algorithm tuning control. % The MATLAB functions FFT, IFFT, FFT2, IFFT2, FFTN, and IFFTN functions % use a library called FFTW. The FFTW library has the ability to % experimentally determine the quickest computational method to compute % the FFT of a particular size and dimensionality. The FFTW function % provides an interface to this run-time algorithm tuning. % % FFTW('planner', METHOD) sets the FFTW library planner method used for % subsequent calls to FFT, IFFT, FFT2, IFFT2, FFTN, and IFFTN. METHOD can % be one of these strings: 'estimate', 'measure', 'patient', and % 'exhaustive', or 'hybrid'. If the planner method is 'estimate', then % the FFTW library chooses algorithms based on a quick heuristic. The % resulting algorithms are sometimes suboptimal. If you specify % 'measure', the FFTW library will experiment with many different % algorithms to compute an FFT of a given size. The library caches the % result in an internal "wisdom" database so that it can reused the % next time an FFT of the same size is computed. Methods 'patient' and % 'exhaustive' are similar to 'measure' except that they take much % longer. If the planner method is 'hybrid', then MATLAB uses the % 'measure' method for FFT dimensions of 8192 or smaller, and it uses % the 'estimate' method for larger dimensions. The default planner % method is 'estimate'. % % METHOD = FFTW('planner') returns the current planner method. % % STR = FFTW('dwisdom') returns the FFTW library's internal % double-precision wisdom database as a string. The string can be saved % and then later reused in a subsequent MATLAB session using the next % syntax. % % STR = FFTW('swisdom') returns the FFTW library's internal % single-precision wisdom database as a string. % % FFTW('dwisdom',STR) loads FFTW wisdom, represented as a string, into the % FFTW library's internal double-precision wisdom database. % FFTW('dwisdom','') or FFTW('dwisdom',[]) clears the internal wisdom % database. % % FFTW('swisdom',STR) loads FFTW wisdom, represented as a string, into the % FFTW library's internal single-precision wisdom database. % FFTW('swisdom','') or FFTW('swisdom',[]) clears the internal wisdom % database. % % For more information about the FFTW library, see http://www.fftw.org. % % See also FFT, FFT2, FFTN, IFFT, IFFT2, IFFTN, FFTSHIFT. % Copyright 1984-2006 The MathWorks, Inc.