Ode45 initial conditions iteration
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I am trying to solve the following 2nd order differential equation, which works fine but I need to iterate the initial conditions, so everytime the ode is solved, the last values for q(:,1) and q(:,2) should be the new value for X and Y respectivley.
%solve_2nd_order_diff
duf=@(t,q)[q(2);f*w^2*cos(w*t)-(Cmech/J)*q(2)-(K1/J)*q(1)-(K3/J)*q(1)^3];
for r=1:length(Rad_speed)%freq of harmonic fluctuations, rad/s
[t,q]=ode45(duf,Time,[X Y]);
Max_values=max(q);
plot(t,q(:,1),'k')
xlabel('TIme,s')
ylabel('Relative Displacement, Rad')
grid
end
采纳的回答
Alan Stevens
2020-11-19
Like so
...
[X Y] = ...
for r=1:length(Rad_speed)%freq of harmonic fluctuations, rad/s
[t,q]=ode45(duf,Time,[X Y]);
[X Y] = [q(end,1) q(end,2)];
...
5 个评论
Adedayo Odeleye
2020-11-19
Alan Stevens
2020-11-19
Can you upload your full code?
Alan Stevens
2020-11-19
编辑：Alan Stevens
2020-11-19
Sorry, I should have written
X = q(end,1); Y = q(end,2);
rather than
[X Y] = [q(end,1) q(end,2)];
Incidentally, your plots will be overwritten unless you use the figure command or hold on (whichever is appropriate.
Adedayo Odeleye
2020-11-19
Alan Stevens
2020-11-19
编辑：Alan Stevens
2020-11-19
Excellent, but notice that your plot and your Max_values will only apply for the last iteration of the loop (they are overwritten every time through the loop). If that is what you want it is probably best to put that piece of coding outside the loop at the end. To store the Max_values (rather than just have them printed in the command window every iteration), you could use
Max_values(r) = max(q);
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