Infinite sum with Bessel's function
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I have this sum with the Bessel function that I am trying to calculate and plot.
Any help would be greatly appreaciated.
Thank you
2 个评论
采纳的回答
n = 60;
sstep = 1;
a_k = J0ROOTS(n,sstep);
r = (0:0.01:1).';
t = 0:0.1:1;
S = zeros(numel(r),numel(t));
for i = 1:numel(t)
S(:,i) = sum(2*besselj(0,a_k.*r)./(a_k.^2.*besselj(1,a_k)).*exp(-a_k.*t(i)),2);
end
plot(r,S)
function x=J0ROOTS(n,sstep)
if nargin==0
n=20;
sstep=1;
elseif nargin==1
sstep=1;
end
J0=@(x) besselj(0,x);
k=0; i=0;
while k<n
i1=i+sstep;
if J0(i)*J0(i1)<0
k=k+1;
x(k)=fzero(J0,[i i1]);
end
i=i1;
end
end
6 个评论
mery
2022-8-11
Torsten
2022-8-11
in my problem, I have 0<=t<inf how can I add this condition?
Incorporated.
mery
2022-8-11
Andrew Omame
2023-3-30
I am having issue running this code on my MATLAB R2014a version.
The error messgae I get is:
Error using .*
Matrix dimensions
must agree.
Please can anyone help on what to do to resolve this.
n = 60;
sstep = 1;
a_k = J0ROOTS(n,sstep);
r = (0:0.01:1).';
t = 0:0.1:1;
S = zeros(numel(r),numel(t));
for i = 1:numel(t)
for k = 1:numel(r)
for l = 1:n
S(k,i) = S(k,i) + 2*besselj(0,a_k(l)*r(k))/(a_k(l)^2*besselj(1,a_k(l)))*exp(-a_k(l)*t(i));
end
end
end
plot(r,S)
function x=J0ROOTS(n,sstep)
if nargin==0
n=20;
sstep=1;
elseif nargin==1
sstep=1;
end
J0=@(x) besselj(0,x);
k=0; i=0;
while k<n
i1=i+sstep;
if J0(i)*J0(i1)<0
k=k+1;
x(k)=fzero(J0,[i i1]);
end
i=i1;
end
end
Andrew
2023-4-20
This has now worked on my MATLAB R2014a version. Thank you very much
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