MATLAB: Struggling to use ode 45

ode45

So here is my code: sys(m,
A0= 0.03;
m0= [0,0.1,0.3];
p0= [0.1,0.4,0.5];
mdot(1) = -m0(1) + 60*(5-A0)/(1+p0(1)^2) +A0;
mdot(2) = -m0(2) + 60*(5-A0)/(1+p0(2)^2) +A0;
mdot(3) = -m0(3) + 60*(5-A0)/(1+p0(3)^2) +A0;
mdot=[mdot(1),mdot(2),mdot(3)];
pdot(1)=-0.2*(p0(1)-m0(1));
pdot(2)=-0.2*(p0(2)-m0(2));
pdot(3)=-0.2*(p0(3)-m0(3));
pdot=[pdot(1),pdot(2),pdot(3)];
t0=0;
tspan=[0,800];
[y,t]=ode45(@odefun,tspan, m0, options);
plot(t,y);
Been staring at it for hours but it wont run.
?? ?

Best Answer

Hi,
try
A0= 0.03;
m0= [0,0.1,0.3];
p0= [0.1,0.4,0.5];
tspan=[0,800];
[t,y]=ode45(@(t,y)odefun(t,y,A0,m0,p0),tspan, [m0 p0]);
plot(t,y);
function y = odefun(t,y,A0,m0,p0)
mdot(1) = -m0(1) + 60*(5-A0)/(1+p0(1)^2) +A0;
mdot(2) = -m0(2) + 60*(5-A0)/(1+p0(2)^2) +A0;
mdot(3) = -m0(3) + 60*(5-A0)/(1+p0(3)^2) +A0;
mdot=[mdot(1),mdot(2),mdot(3)]';
pdot(1)=-0.2*(p0(1)-m0(1));
pdot(2)=-0.2*(p0(2)-m0(2));
pdot(3)=-0.2*(p0(3)-m0(3));
pdot=[pdot(1),pdot(2),pdot(3)]';
y = [mdot;pdot];
end
Best regards
Stephan
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