VC++傅立叶快速变换算法实例源码

Arbitrary Length FFT ------------------------------------------------------------------------ NOTE : This is copyrighted material, NOT public domain. See below. ------------------------------------------------------------------------ Contents: This packet contains the C source for a mixed-radix FFT routine. It performs a fast discrete Fourier transform (FFT) of a complex sequence, x, of an arbitrary length, n. The output, y, is also a complex sequence of length n. y[k] = sum(x[m]*exp(-i*2*pi*k*m/n), m=0..(n-1)), k=0,...,(n-1) The largest prime factor of n must be less than or equal to the constant, maxPrimeFactor defined in mixfft.c. The input/output variables are each stored in two arrays comprising the real part and the imaginary part respectively. The routine is accompanied by a demo program, fftbench.c, that demonstrates the numerical capabilities. It measures the execution time as well. If you wish to test the capabilities of another FFT routine, the fftbench.c is easy to modify. ------------------------------------------------------------------------ Filelist: mixfft.c 21.120 001030 The C source for the mixed-radix FFT. fftbench.c 8.724 001030 The C source for FFT benchmark program. fftbench.exe 62.976 001030 The PC executable. readme.txt This file. ------------------------------------------------------------------------ Platforms: PC: The included fftbench.exe was generated using the Microsoft Visual C++ compiler with the following compile options: /nologo /Gs /G2 /W4 /AH /Ox /D "NDEBUG" /D "_DOS" /FR It was tested on a 50MHz 486DX. Please refer to fftbench.c for some benchmarks. (jjn, March 1996) Other: Your experience with other platforms are warmly welcomed. Please e-mail me. ------------------------------------------------------------------------ Conditions: The source code in this packet is copyrighted material. Non-commercial use of the source code is free. A $100 fee must be paid if used commercially. Please contact me at jjn@get2net.dk and register your copy. The $100 fee includes up to one hour of assistance related to your use of the code. A trial period of 14 days is allowed. If the code is used for professional (paid) research and development for non-profit organisations like universities a reduced fee of $20 must be paid. The commercial license allows you to include the compiled code in a product or to use the code on a regular basis. You are however NOT allowed to sell the source code. Distribution of the complete unaltered package, including this file, is free. This includes commercial CD's. ------------------------------------------------------------------------ Author: Jens Joergen Nielsen For non-commercial use only. Bakkehusene 54 A $100 fee must be paid if used 2970 Hoersholm commercially. Please contact. DENMARK mailto:jjn@get2net.dk All rights reserved. October 2000. Check my homepage for updates and FAQ's http://home.get2net.dk/jjn ------------------------------------------------------------------------ Release notes: V.0.1 950301 Initial MIXFFT release. V.0.3 960317 Input/output variables have separate arrays for real and imag part. The speed of prime factors larger than 7 is more than doubled. V.0.4 980103 e-mail address changed. V.0.5 001030 Memory allocation in FFTBench changed, now calloc is used. Error reporting when primefactor is larger than maxPrimeFactor has been corrected. ------------------------------------------------------------------------