How can I output intermediate vaviables when using ode45 funcion?

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huan tu
huan tu 2013-7-16
I want to output an intermediate vaviable when using ode45 funcion.In the following codes, a_k is the function of w, I want to output the value of a_k at every step, which is [-110:1:115],and plot(w,a_k). Is there any way to solve the problem? Thank you all!
function main
CA_span= -110:1:115;
Qf0=0;
mf0=0.005;
m0=2.5;
y0=[Qf0 mf0 m0];
[T,Y]=ode45(@hrr_ode1,CA_span,y0);
end
function dy=hrr_ode1(w,y)
T=p(w)*Vz(w)/(y(3)*R);
a_k=(y(3)-y(2))/(L0*y(2));
% a_k is the function of w, I want to output the value of a_k at every step, which is [-110:1:115]
x1=0.001*p(w)*dVzdw(w);
x2=dQ0dw(T,p(w),w);
x3=(1/(R/1000))*C_v(T,a_k)*(Vz(w)*dpdfai(w)+p(w)*dVzdw(w))*0.001;
x4=U(T,a_k);
x5=C_v(T,a_k)*T;
x6=y(3)*U_ak(T,a_k)*a_k/y(2);
dy=zeros(3,1);
if w<0
dy(1)=0;
dy(2)=0;
dy(3)=0;
else
dy(1)=(x1+x2+x3)/(1-(1/Hu)*(x4-x5-x6));
dy(2)=max( dy(1)/Hu,0);
dy(3)=max( dy(1)/Hu,0);
end
end

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采纳的回答

Grzegorz Knor
Grzegorz Knor 2013-7-16
You can use OutputFcn to do this. Just add options to ode45 in this way:
options = odeset('OutputFcn',@myfun);
[T,Y]=ode45(@hrr_ode1,CA_span,y0);
And define myfun as:
function status = myfun(t,y,flag)
.
.
.
switch(flag)
case 'init'
.
.
.
case 'done'
.
.
.
end
end
status = 0;
You have to fill dots in the code above with proper commands.

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