About this ode function

I want to calculate this ode function with initial value y(4)=-3. But it shows not enough input error at line

dy= (K1*t+K2*y-az)/(K3*t+K4*y+kz); Can someone help please? Thanks!

function dy = coexistline(t,y)
K1 =4.9493e-04;
K2 =-1.0058e-04;
K3 =1.0058e-04;
K4 =0.0081;
az = 0.088235;
kz = -1.65625;

%dy = zeros(1,1);    % a column vector
dy= (K1*t+K2*y-az)/(K3*t+K4*y+kz);

options = odeset('RelTol',1e-4,'AbsTol',[1e-4 1e-4 1e-5]);
[T,Y] = ode45(@coexistline,[-10 10],-3,options);
plot(T,Y,'-o')

Answer 1

[Stephen Carter]

I think 'AbsTol',[1e-4 1e-4 1e-5] is your problem. Since your solution has only one component for each timestep, I believe your tolerance also needs to be scalar. Try 'AbsTol',1e-4 instead.

And... looking further at what you said... you say you want initial value y(4)=-3. Do you mean you want y to equal -3 at t=4? If so, then your input is wrong. You seem to put y as -3 at time -10.

For additional help see http://www.mathworks.com/help/matlab/ref/ode45.html

[qingze]

How should I set y(4)=-3 as initial value?