# get_fftw_wisdom

return fftw wisdom

## Calling Sequence

    [txt]=get_fftw_wisdom()

## Arguments

txt

  String matrix that contains fftw wisdom.

## Caveat

This function is not implemented in Scilab versions which use the MKL intel library (Scilab official versions for windows in particular).

## Description

This function return the fftw wisdom in a string matrix. Using `get_fftw_wisdom` and `set_fftw_wisdom` allows to optimize fft efficiency if many calls have to be done on with same data sizes and same options for the fft function.

## Examples

    sample_rate=1000;
    t = 0:1/sample_rate:40;
    N=size(t,'*'); //number of samples
    s=sin(2*%pi*50*t)+sin(2*%pi*70*t+%pi/4)+grand(1,N,'nor',0,1);
    fftw_forget_wisdom();
    timer();y=fft(s);t1=timer() //first call
    timer();y=fft(s);t2=timer()  //second call uses preserved wisdom
    t1/t2
    wisdom1=get_fftw_wisdom(); //preserve current wisdom
    //realize a different fft
    A = zeros(256,256);
    A(5:24,13:17) = 1;
    X = fft(A);

    //Create a new signal with same size as s
    s1=sin(2*%pi*10*t)+sin(2*%pi*7*t+%pi/4)+5*grand(1,N,'nor',0,1);
    //restore preserved wisdom
    set_fftw_wisdom(wisdom1);
    timer();y=fft(s);t3=timer()
    t3/t2

## See Also

- fft
- set_fftw_wisdom
- fftw_forget_wisdom