matlab derivative
N=256;
t=pi*[-N:N-1]/N;
f=exp(-(t.^2)/(0.5));
f=f-mean(f);
F=fftshift(fft(f));
figure(1);clf;set(gcf,'Renderer','zbuffer');
for n=0:0.1:4
Fn=(j*t).^n .* F;
fn=ifft(fftshift(Fn));fn=fn/max(abs(fn));plot(real(fn));
text(20,1.0,sprintf('%0.2f',n));
grid on;axis( [0 2*N -1.2 1.2]);
axis square;drawnow;
end;
creatively acquired from :
http://www.cs.dartmouth.edu/~farid/r...fracderiv.html
Hi, rntsay!
I'm also interested in so-called fractional calculus, we will see if it's really interesting for us...
Look in attached file.
More comments on this topic are welcome!
Best regards,
Eirp
There is a book:
The Fractional Calculus by Keith B. Oldman and Jerome Spanier
Academic Press 1974
It is an intuitive introduction to this subject.
I read through this paper and to be honest it looks more like a curiosity than anything substantial. If the object is to study symmetries and invariances of maxwell's equations (as an aid in simplifying some field calculations), then I'm sure I've seen better settings for the problem than here...but these can sometimes be too theoretical. If I remember right,for example, maxwell's equations (in vaccum) are inavariant under all conformal transformations (which include lorentz transformations), they are also invariant under "duality" (E,B) -> (B,-E) In the presence of sources (currents and charges) the symmetries are different, but I don't remember the details of that. So maybe conformal symmetries is a
better subject to look at than fractional calculus, unless fractional
differentiation is actually conformal!...my math isn't good enough to answer that. Come to think of it my physics knowledge isn't that good in this area either, so maybe you shouldn't quote me on any of the above!
r.n.
Hi, boy!
Please, do you have it?
Can you scan&share? I'll very appreciate it!
Thanks,
Eirp
Dear all, fractional calculus is nowadays very useful for solving the problems of control system, soft condense matter etc.. to know more you can go through the book "MATHEMATICO--PHYSICS OF GENERALIZED CALCULUS" by SHANTANU DAS (BARC, INDIA).
thank you...
---------- Post added at 06:28 ---------- Previous post was at 06:27 ----------
but i want some more basics of fractional calculus.. if anyone have anything pls share..
some ppts of fractional calculus by Mr. Shantanu Das (Scientist,BARC) are attached. if any one interested please go through...