Looping ode45 Increasing Parameter
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I need to loop ode45 and after each iteration a parameter (mp) should increase and then store all solutions in y_end based on ye. What seems to be incorrect in this code? It doesn't seem to be increasing mp.
mp = 0.05:0.01:100; % start at 0.05, increment by 0.01 until 100
y_end = zeros(length(mp)); % final values 4 column 9996 rows?
for ii = 1:length(mp);
Opt = odeset('Events', @myEvent);
[t, y,te,ye,ie] = ode45(@(t, y)odefun(t, y, mp), [0 pi], [O P J K], Opt);
y_end(ii) = ye(1); % the iith entry of y_end should be given by the corresponding ye values, where ye stores 4 variables solved each iteration
end
function [value, isterminal, direction] = myEvent(t, y);
value = double((any(y(1,1:end) >= pi))); % stop at theta ~ pi?
isterminal = 1; % stop the process
direction = 0;
end
function dydt = odefun(t, y, mp) % y = [y z y1 z1]
dydt = zeros(4,1); % A vector of zeros
dydt(1) = y(3); % y_dot = y1
dydt(2) = y(4); % z_dot = z1
dydt(3) = ((g*sin(y(1))*( mcw * lsa - m * lcg - mp * lla)+(mp * lla)*(g*sin(y(2))*cos(y(1)-y(2))-ls*dydt(2).^2*sin(y(1)-y(2))-lla*dydt(1).^2*cos(y(1)-y(2))*sin(y(1)-y(2)))))/((mcw * (lsa)^2) + (1/12 * m * (lla + lsa)^2 + m * (lcg)^2) + mp*(lla).^2*(sin(y(1)-y(2)))^2); % second derivative of theta
dydt(4) = ((lla*((dydt(1).^2*sin(y(1)-y(2))-dydt(3)*cos(y(1)-y(2)))-g*sin(y(2)))))/ls; % second derivative of phi
end
2 个评论
Jan
2018-6-21
It is impolite, if you remove the question after an answer has been given. It reduces the chance that the forum will care about your questions in the future.
Rena Berman
2018-6-21
(Answers Dev) Restored edit
回答（1 个）
Star Strider
2018-6-19
You did not post your constants, so I cannot run your code.
Most likely, you need to subscript ‘mp’ in your ‘odefun’ call in your ode45 call.
Try this:
[t,y,te,ye,ie] = ode45(@(t, y)odefun(t, y, mp(ii)), [0 pi], [O P J K], Opt);
↑ ← SUBSCRIPT
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2018-6-21
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