Unable to perform assignment because the size of the left side is 1-by-1

I'm writing code to perform a signal simulation (stochastic systems) and it throws me the error "Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-2." in the code line "L(k,k+i)=L(k,k+i-1)*Phi*(ones(1, k+i)-K(k+i));" of course, I understand that it is a dimensionality problem, I know that the left side is a scalar and the right side a vector of 2 columns. However, I do not know how to solve it, I have tried to modify the dimensions of L(k, k + i) but it does not work for me. I appreciate any help in this regard.

%%%%%Condiciones iniciales
Phi=0.95;
n=50;
P0=1;
x0=sqrt(P0)*randn(1,1);
Q0=0.1;
w0=sqrt(Q0)*randn(1,1);
x(1)=Phi*x0+w0;

%%%%Estado%%%%%%
for k=1:n
    Q(k)=0.1;
    w(k)=sqrt(Q(k))*randn(1,1);
    x(k+1)=Phi*x(k)+w(k);
end

%%%%%Observaciones%%%%%
R0=0.5;
v0=sqrt(R0)*randn(1,1);
z0=x0+v0;
for k=1:n
    R(k)=0.5;
    v(k)=sqrt(R(k))*randn(1,1);
    z(k)=x(k)+v(k);
end

%%%%Filtrado%%%
Cpred0=P0;
K0=Cpred0*[P0+R0]^-1;
fil0=K0*z0;
Cfil0=[1-K0]*Cpred0;
pred(1)=Phi*fil0;
Cpred(1)=Phi^2*Cfil0+Q0;
for k=1:n
    K(k)=Cpred(k)*[Cpred(k)+R(k)]^-1;
    fil(k)=pred(k)+K(k)*[z(k)-pred(k)];
    Cfil(k)=[1-K(k)]*Cpred(k);
    pred(k+1)=Phi*fil(k);
    Cpred(k+1)=Phi^2*Cfil(k)+Q(k);
end

%%%%%Suavizamiento de punto fijo N=2%%%%%
for k=1:n
    L(k,k)=Cfil(k);
    pf(k,k)=fil(k);
    Cpf(k,k)=Cfil(k);
end

for k=1:n
    for i=1:2
        kpf(k,k+i)=L(k,k+i-1)*Phi*(Cpred(k+i))^-1;
        L(k,k+i)=L(k,k+i-1)*Phi*(ones(1,k+i)-K(k+i));
        pf(k,k+i)=pf(k,k+i-1)+kpf(k,k+i)*(z(k+i)-pred(k+i));
        Cpf(k,k+i)=Cpf(k,k+i-1)-kpf(k,k+i)*(pred(k+i)+R(k))*kpf(k,k+i);
    end
end

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-2.

[the cyclist]

Great. (I deleted my comment about the other problem, after I saw you had fixed it.)

Answer 1

[the cyclist]

My best guess as to the problem is that in this expression

ones(1,k+i)-K(k+i)

you don't really intend to add a vector of ones to the scalar K(k+i). Did you just intend to add the scalar 1? If so, you could do

1 + K(k+i)

[César Guillermo Rendón Mayorga]

You're right. I've already changed it but it throws me "Index exceeds the number of array elements. Index must not exceed 50" in the same line and I don´t understand why it is with a larger size

[the cyclist]

When k==49, and i==2, you are trying to access the 51st column of a 50-column array.

You possibly need

for k=1:n-2 % instead of k=1:n

but then I don't know if you are truly calculating the result you need.

[César Guillermo Rendón Mayorga]

I've done the modification, it seems to work for what I need. I'll continue to work for now. Thank you very much for your help!