Euler's method for 2nd order ODE
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I am trying to run a code for solving 2nd order ODE but I have no idea where is my mistake in the following code:
function f=f(t0,x0,y0,N)
h=0.01;
N=5;
t0=0;
x0=0;
y0=0;
H=zeros(1,N+1);
T=zeros(1,N+1);
X=zeros(1,N+1);
Y=zeros(1,N+1);
H(1)=h; T(1)=t0; X(1)=x0; Y(1)=y0;
for j=1:N
T(j+1)=T(j)+H(j);
X(j+1)=X(j)+H(j)*Y(j);
Y(j+1)=Y(j)+H(j)*ahat(T(j),X(j),Y(j));
H(j+1)=H(j)*(1-H(j));
end
plot [T X]
plot [T Y]
15 个评论
Geoff Hayes
2019-7-5
oday - since the code is not explicitly writing anything to the console and because all lines are terminated with a semi-colon, then you will not see any output. As for the error...which array/variable does that correspond to?
回答(1 个)
Vaibhav Tomar
2019-7-4
Can you please specify the values of T, Y and X. Without that it's difficult to say why the code is throwing errors. I'd suggest to look for an example for second order ODE algorithm.
You can try this alternate code:
% x1=y
%x2=dy
%then
%dx1=dy=x2
%dx2=d2y=-w^2*y=-w^2*x1
%save this function as yourfcn
function dx=yourfcn(t,x)
w=1
dx(1)=x(2)
dx(2)=-w^2*x(1)
%Then call the ode45 function
[t,x]=ode45(@yourfcn,[0,pi],[0 0])
%Then deduce y
y=x(:,1)
另请参阅
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