From 0a109da279e9df66fb5ea7d6bdaeffed16592f02 Mon Sep 17 00:00:00 2001 From: Thomas Grill Date: Mon, 2 Dec 2002 17:50:01 +0000 Subject: "version 0.1.1" svn path=/trunk/; revision=266 --- externals/grill/vasp/mixfft.txt | 85 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 externals/grill/vasp/mixfft.txt (limited to 'externals/grill/vasp/mixfft.txt') diff --git a/externals/grill/vasp/mixfft.txt b/externals/grill/vasp/mixfft.txt new file mode 100644 index 00000000..03262e52 --- /dev/null +++ b/externals/grill/vasp/mixfft.txt @@ -0,0 +1,85 @@ + + 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. + + + ------------------------------------------------------------------------ -- cgit v1.2.1