Nested for loop fourier series

3 views (last 30 days)
Carlos So
Carlos So on 11 Jun 2014
Commented: Carlos So on 11 Jun 2014
I'm trying to use a nested for loop to do a fourier series. I have to evaluate n to 10 then use the new n for each pass to analyze t. n=10 t=10 I'm not quite sure how to do the nested for loop section. Any help is highly appreciated
This is what I have so far
y = [1.0668 1.8288 2.7432 3.5662 4:2977 4.6634 2.5908 2.3165 2.6518 3.0785 3.3223 ... 2.6213 0.3200 - 0.5791 - 1.0668 - 1.4326 - 1.4630 - 1.1887 - 0.5182 0.1524 1.0668];
n=10
T=2*pi %Period
O=2*pi/T %omega
t=linspace(0,2*pi,length(y))
a0=1/2*pi*trapz(t,y)
an(i)=(2/T)*trapz(t,y.*cos((n(i)*O.*t))) %finds an for i=n
bn(i)=(2/T)*trapz(t,y.*sin((n(i)*O.*t))) %finds bn for i=n
for i=1:n
for j=1:length(y)
n(i)=i
an1(j)=(2/T)*trapz(t,y.*cos((n(i)*O.*t))) %finds an1 using each n and a different t each loop
bn1(j)=(2/T)*trapz(t,y.*sin((n(i)*O.*t))) %finds bn1 using each n and a different t each loop
end
end
M=a0+an1+bn1

Answers (1)

Andrei Bobrov
Andrei Bobrov on 11 Jun 2014
Edited: Andrei Bobrov on 11 Jun 2014
To = 2*pi;
s = numel(y);
t = linspace(0,To,s).';
n = 1:10;
ang = t*n;
a0_1 = 1/To*trapz(t,y);
abn_1 = 2/To*trapz(t,[bsxfun(@times,y,[cos(ang), sin(ang)]);
an_1 = abn_1(n);
bn_1 = abn_1(n(end)+n);
or with use fft
nn = numel(y);
x = fft(y(1:end-1));
a0_1 = x(1)/(nn-1);
abn_2 = 2/(nn-1)*x(2:end);
  1 Comment
Carlos So
Carlos So on 11 Jun 2014
Sorry, but it has to be done using a nested for loop.

Sign in to comment.

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!