Save variables while using ode solver
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[t,y]=ode45(@fun,tspan,yo);
function dy=fun(t,y)
dy=zeros(3,1);
constant1 = k1*y(3)
dy(1)= constant1;
dy(2)=f1(y(3),y(2))
dy(3)=f2(y(1),y(2))
end
I want to save the variable, constant1, each time the ode solver calls the function fun.
Is there a way to get the iteration count?
If yes, I can use
save_constant1(iter) = constant1.
Any suggestions?
2 个评论
Steven Lord
2019-10-24
What do you want to happen if the ODE solver evaluates your function for a particular time step but then rejects that step and evaluates your function at an earlier time (a smaller time step from the previous time?)
Deepa Maheshvare
2019-10-25
采纳的回答
Dinesh Yadav
2019-10-29
What you can try is at every iteration save the variables into a .mat file
save('odef.mat', 'constant1', '-append')
This will append the new values and keep your old values also.
Hope it helps.
2 个评论
alesmaz
2019-11-1
Hi, I've tried your method in my code, where p is a vector of 4 parameters that I need to save at each ODE iteration in order to calculate their confidence intervals. I've put your string before the 'end' but my code overwrites always p without keeping the previous one.
Is there a way to save p at each ODE iteration without losing the one obtained in the previous iteration? Thank you.
function f=bernardode(p,t)
t=temposp;
options=odeset('AbsTol',1e-6,'RelTol',1e-6);
[T,Z]=ode45(@bernard2,t,z0,options);
function dz = bernard2(t,z)
dzdt=zeros(4,1);
dzdt(1)=-(p(3)*(1-qmin/z(1)))*(((Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2))))/(p(4)+(Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2)))))*z(1);
dzdt(2)=(p(3)*(1-qmin/z(1)))*(((Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2))))/(p(4)+(Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2)))))*z(2);
dzdt(3)=p(2)*z(4)+(p(3)*(1-qmin/z(1)))*(((Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2))))/(p(4)+(Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2)))))*(1-p(1)-z(3));
dzdt(4)=(p(1)-z(4))*(p(3)*(1-qmin/z(1)))*(((Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2))))/(p(4)+(Io/(sigma*L*z(2)))*(1-exp(-sigma*L*z(2)))))-p(2)*z(4);
dz=dzdt;
end
f=Z;
end
Ibrahim Bakry
2021-5-5
Not working with ode45
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