RK4 help (someone help fix this)

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Aya
Aya 2024-11-25
评论： Aya 2024-12-4，18:56
so i made the code but i only get the first two values then the values start to equal zeros wich shouldnt hapend.
this is the code :
x_start=0; %valeeur initial de x
x_end=1; %valeur final de x
n_nodes=20;
h=(x_end-x_start)/(n_nodes-1);
x=linspace(x_start, x_end, n_nodes);
y_RK4=zeros(1,n_nodes);
y_RK4(1)=3;
f=@(x,y) (-0.3*y+2*exp(-x));
for i=1,n_nodes-1;
k1=h*f(x(i),y_RK4(i));
k2=h*f((x(i)+(h/2)),(y_RK4(i)+(k1/2)));
k3=h*f((x(i)+(h/2)),(y_RK4(i)+(k2/2)));
k4=h*f((x(i)+h),(y_RK4(i)+k3));
y_RK4(i+1)=y_RK4(i)+(k1+(2*k2)+(2*k3)+k4)/6;
end

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采纳的回答

Torsten
Torsten 2024-11-25，22:51
Use
for i=1:n_nodes-1
instead of
for i=1,n_nodes-1;
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Image Analyst
Image Analyst 2024-11-27，4:25
If this Answer solves your original question, then could you please click the "Accept this answer" link to award the answerer with "reputation points" for their efforts in helping you? They'd appreciate it. Thanks in advance. 🙂 Note: you can only accept one answer (so pick the best one) but you can click the "Vote" icon for as many Answers as you want. Voting for an answer will also award reputation points.
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Aya
Aya 2024-12-4，18:56
aha i did thanks man im new to matlab so i didnt know much :)))))

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