Problem with ODE45

I should solve 2 coupled matrix differential equations. for that, I have created a script (m-file) in which I have defined all matrices with constant values. I have also created another script for a function and call this function in the first m-file. Finally I have used ode45 to solve the function, but it doesn't work!

The systom to be solved (A, L, R and P are matrices with constant components):

My function (which its name is 'myode'):

                                                        function dydt=myode(t,y,A,R,L,P)
                                                        [m n]=size(P);
                                                        [k l]=size(L);
                                                        for a=1:m
                                                            dydt(a)=P(a,:)*y(a);
                                                        end
                                                        
                                                        for b=1:k
                                                            dydt(m+b)=inv(L)*(A*y(m+b)-R*y(b));
                                                        end
                                                        end

My first script (m-file):

                                    tspan=linspace(5,5.010,11);
                                    i_0=transpose([0.355 -0.355 2.046 0.711 0 0.709]);
                                    u_0=transpose([1002.40 1001.98 1012.04 986.11]);
                                    y0=[u_0;i_0];
                                    [T Y]=ode45(@(t,y) myode(t,y,A,R,L,P),tspan,y0)

==> but when I run my first script, the following error pops up:

Error in Test>@(t,y)myode(t,y,A,R,L,P)

Error in odearguments (line 87)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode23 (line 114)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in Test (line 58)

[T Y]=ode23(@(t,y) myode(t,y,A,R,L,P),tspan,y0)

Anyone has an idea what the problem is?

[Saeed Ahmadzadeh Mahboobi]

And when I run the function alone, the error is:

Not enough input arguments.

Error in myode2 (line 2)

[m n]=size(P);

[darova]

u and i have different sizes

You also passing different sizes

i_0=transpose([0.355 -0.355 2.046 0.711 0 0.709]);
u_0=transpose([1002.40 1001.98 1012.04 986.11]);

How to substract ?

I like the way you organized the question

[Saeed Ahmadzadeh Mahboobi]

About the matrix dimensions, when they are multiplied with another marix from left side, the both A*u and R*i become matrices of the same dimensions.

[darova]

Can you show A and R matrices?

[Walter Roberson]

We will need more of your code to test with.

[Richard Brown]

You're definitely going to have issues trying to build your derivative one term at a time (look at the term involvint inv(L) for a start). why can't you just do the following?

function dydt=myode(t,y,A,R,L,P)
u = y(1:3);
i = y(4:7);

dydt = [L\(A*u - R*i); P*i];
end

will be much easier to troubleshoot.