Model simulation Code for SEIR

function seir_simulation()

    % Parameters
    beta = 0.3; % Effective contact rate without control
    sigma = 1/5; % Rate of exposed individuals becoming infectious
    gamma = 1/10; % Rate of infectious individuals recovering
    N = 1000; % Total population
    E0 = 1; % Initial number of exposed individuals
    I0 = 1; % Initial number of infectious individuals
    R0 = 0; % Initial number of recovered individuals
    S0 = N - E0 - I0 - R0; % Initial number of susceptible individuals
    tspan = [0 200]; % Time span for simulation

    % SEIR model without control
    function dydt = seir_model(t, y)
        S = y(1);
        E = y(2);
        I = y(3);
        R = y(4);

        dS = -beta*S*I/N;
        dE = beta*S*I/N - sigma*E;
        dI = sigma*E - gamma*I;
        dR = gamma*I;
        dydt = [dS; dE; dI; dR];
    end

    % Solving SEIR model without control
    [t, y] = ode45(@seir_model, tspan, [S0 E0 I0 R0]);

    % Plotting SEIR model without control
    figure;
    plot(t, y(:,1), 'b', t, y(:,2), 'r', t, y(:,3), 'g', t, y(:,4), 'k');
    legend('Susceptible', 'Exposed', 'Infectious', 'Recovered');
    xlabel('Time');
    ylabel('Population');
    title('SEIR Epidemiological Model without Control');

    % SEIR model with control
    u_values = [0.1 0.2 0.3 0.4 0.5]; % Different values of control u(t)

    for u = u_values
        % Apply control to beta
        beta_controlled = beta*u;

        % SEIR model with control
        function dydt = seir_model_control(t, y)
            S = y(1);
            E = y(2);
            I = y(3);
            R = y(4);

            dS = -beta_controlled*S*I/N;
            dE = beta_controlled*S*I/N - sigma*E;
            dI = sigma*E - gamma*I;
            dR = gamma*I;
            dydt = [dS; dE; dI; dR];
        end

        % Solving SEIR model with control
        [t_control, y_control] = ode45(@seir_model_control, tspan, [S0 E0 I0 R0]);

        % Plotting SEIR model with control
        figure;
        plot(t_control, y_control(:,1), 'b', t_control, y_control(:,2), 'r', t_control, y_control(:,3), 'g', t_control, y_control(:,4), 'k');
        legend('Susceptible', 'Exposed', 'Infectious', 'Recovered');
        xlabel('Time');
        ylabel('Population');
        title(['SEIR Epidemiological Model with Control u(t) = ' num2str(u)]);
    end

end Error Misplaced function I am learning the above code but I don't know how to place the function properly.I need help.