index exeeds matrix dimensions error

2018 5 6
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更新时间：2018 5 6
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t0 = 0;
tf = 0.4;
h = 0.1;
y0 = [2,4];
f = @(y,t) [-2*y(1) + 5*exp(-t); (-y(1).*(y(2).^2))/2];
prob2res1 = myEuler3(f,y0,t0,tf,h)
[t, prob2res4] = ode45(f,[0,0.4],y0)
my euler function is below
function [sol] = myEuler3(F, y0, ti, tf, h)
t = ti:h:tf;
y = zeros(length(y0),length(t));
y(:,1) = y0;
for i = 2:length(t)
y(:,i) = y(:,i-1) + h*F(t(i-1),y(:,i-1));
end
sol = [ t; y ];
end

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Ameer Hamza
Ameer Hamza 2018-5-6
编辑：Ameer Hamza 2018-5-6

0 个投票

The first argument in anonymous function f should be time t. Reverse the order like this
f = @(t, y) [-2*y(1) + 5*exp(-t); (-y(1).*(y(2).^2))/2];

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Susan Santiago
Susan Santiago 2018-5-6
Thank you so much! I've been stuck on this for hours. Is there any reason why t needs to be first?
Ameer Hamza
Ameer Hamza 2018-5-6
ode45 documentation mention that it consider that input should be of the form f(t, y).

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