Help for some functions



Hello,

i am a postgraduate student in Applied Informatics and i am using maxima
about a month.

I have problem using some functions of maxima and i will need your help.

The functions that i cannot understand are these: fft, ifft, dgesvd and
gamma.

1) fft

I would like to do compute this:


x: makelist(i*random(1000),i,1,100);
b:fft(x);

but i get an error.

I used to perform this operation in matlab like this, but i can't figure out
how this function works.


2) ifft

I would like to do compute this:


x: makelist(i*random(1000),i,1,100);
b:ift(x);

but i get an error.


3) dgesvd

h [i, j] := (1 + i*random(1000) + j)/(j*random(1000))+random(1000);
x: genmatrix(h,10,10);
b: dgesvd(x);

but again i get an error.



4) gamma

h [i, j] := (1 + i*random(1000) + j)/(j*random(1000))+random(1000);
x: genmatrix(h,10,10);
b: gamma(x);

but again i get an error.




I use Maxima 5-16.3 under Windows.


Thank you anyway,
Nick