Not all graphs appear at the same time

I'm graphing the results of a code. I need four graphs to appear in the same plane and I'm using the "hold on/hold off" instruction but I only see three... I've tried to modify the order, remove one and put another, etc. But I never see all four at the same time. I attach all the code and 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
    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-2
    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*(1-K(k+i-1));
        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

for k=1:n
    pf1(k)=pf(k,k);
    Cpf1(k)=Cpf(k,k);
end

hold on
plot(x)
plot(z,'--')
plot(fil)
plot(pf1)
hold off
title('Estimación de estados con filtro de Kalman y suavizamiento punto fijo')
xlabel('Tiempos k')
legend('Estados simulados','Observaciones','Filtrado','Suavizado punto fijo')

Answer 1

[Steven Lord]

%%%%%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; % Adding some semicolons
    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-2
    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*(1-K(k+i-1));
        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

for k=1:n
    pf1(k)=pf(k,k);
    Cpf1(k)=Cpf(k,k);
end

hold on
plot(x)
plot(z,'--')
plot(fil)
plot(pf1)
hold off
title('Estimación de estados con filtro de Kalman y suavizamiento punto fijo')
xlabel('Tiempos k')
legend('Estados simulados','Observaciones','Filtrado','Suavizado punto fijo')

Let's check to see if one of your lines is being plotted outside the Y limits of your axes.

[minval, maxval] = bounds(x)

minval = -2.0632

maxval = 0.1662

[minval, maxval] = bounds(z)

minval = -2.5666

maxval = 0.7799

[minval, maxval] = bounds(fil)

minval = -1.9089

maxval = 0.1863

[minval, maxval] = bounds(pf1)

minval = -1.9089

maxval = 0.1863

So no, all four are being plotted within the bounds of the Y axis limits. But from the fact that the bounds of fil and pf1 are displayed the same, I'm suspicious if they have the exact same values.

norm(fil-pf1)

ans = 0

Yes, they do. So all four of your lines are being plotted, it's just that one of them is being plotted exactly on top of another.