X-Git-Url: http://gitweb.scilab.org/?p=scilab.git;a=blobdiff_plain;f=scilab%2Fmodules%2Ffftw%2Fhelp%2Fen_US%2Ffftw.xml;h=d03e006d62faaac1061154c86601400db03556e5;hp=916a14bec2d6c71fcee05cd557d743db314f3748;hb=76241ab3c905485537f1e77edf72ff704776d653;hpb=ed5c476a7c3db52abb1f32b309b5788ac0ad18d7 diff --git a/scilab/modules/fftw/help/en_US/fftw.xml b/scilab/modules/fftw/help/en_US/fftw.xml index 916a14b..d03e006 100644 --- a/scilab/modules/fftw/help/en_US/fftw.xml +++ b/scilab/modules/fftw/help/en_US/fftw.xml @@ -1,67 +1,106 @@ - - - - eng - fftw - Scilab Function - October 2006 - fast fourier transform that use fftw library - - [y]=fftw(x) - [y]=fftw(x,sign) - [y]=fftw(x,sign,dim,incr) - [y]=fftw(x,sign,[dim1 dim2 ...dimN],[incr1 incr2 ...incrN]) - - - - - y,x - - : matrix/vector of real/complex data. Input/output data to be transformed. - - - - sign - - : Integer. 1 or -1. Set direct or inverse transform. - - - - dim - - : integer. Set the dimension (the length) of the transform. - - - - incr - - : integer. Set the stride (the span) of the transform. - - - - - -

- This function realizes direct/inverse Discrete Fourier Transform (DFT) with the help of the FFTW library. -

-

- One can compute vector, 2D, M-D transform with this function. -

-

- For more details of fftw syntax see fft scilab function. -

-

- For more details about FFTW library see FFTW Web site : http://www.fftw.org . -

- - Remark : fftw function automaticaly stores his last parameters in memory to re-use it in a second time. - - - This results on a time computation improvement when consecutives calls (with same parameters) are used. - -
- - + + + + October 2006 + + + + fftw + + fast fourier transform that use fftw library + + + + Calling Sequence + + [y]=fftw(x) +[y]=fftw(x,sign) +[y]=fftw(x,sign,dim,incr) +[y]=fftw(x,sign,[dim1 dim2 ...dimN],[incr1 incr2 ...incrN]) + + + + Parameters + + + + y,x + + + matrix/vector of real/complex data. Input/output data to be + transformed. + + + + + sign + + + Integer. 1 or -1. Set direct or inverse transform. + + + + + dim + + + integer. Set the dimension (the length) of the + transform. + + + + + incr + + + integer. Set the stride (the span) of the transform. + + + + + + + Description + + This function realizes direct/inverse Discrete Fourier Transform + (DFT) with the help of the FFTW library. + + One can compute vector, 2D, M-D transform with this function. + + For more details of fftw syntax see fft scilab function. + + For more details about FFTW library see FFTW Web site : http://www.fftw.org + + + Remark : fftw function automaticaly stores his last parameters in + memory to re-use it in a second time. + + This results on a time computation improvement when consecutives + calls (with same parameters) are used. + + + + Examples + + + //simple vector direct transform a = rand(50,1)+%i*rand(50,1); y = fftw(a); @@ -85,20 +124,29 @@ //More efficient than old y = fftw(a,-1,[5 6 4],[1 5 30]); b = fftw(y,1,[5 6 4],[1 5 30]); - ]]> - - - - fftw_flags - get_fftw_wisdom - set_fftw_wisdom - fftw_forget_wisdom - - - -

- Matteo Frigo and Steven G. Johnson, "FFTW Manual fo version 3.1.2" June 2006. Available : http://www.fftw.org -

-
- -
+ + + + + + See Also + + + fftw_flags + + get_fftw_wisdom + + set_fftw_wisdom + + fftw_forget_wisdom + + + + + Bibliography + + Matteo Frigo and Steven G. Johnson, "FFTW Manual fo version 3.1.2" + June 2006. Available : http://www.fftw.org + + \ No newline at end of file