Please expalin the error

Hi,

I am using the following code to estimate parameters of an ARCH(1) model.

However, I am getting the given error.

Is there any way to correct it please?

    Code:
    clc;
  clear;

p=1;

T = 1000;

a0 = 0.1; a1 = 0.4; 

ra = zeros(T+2000,1);
seed=123;
rng(seed);

%ra = randn(T+2000,1); 
 ra = trnd(5,T+2000,1); 

epsi=zeros(T+2000,1);
simsig=zeros(T+2000,1);

unvar = a0/(1-a1);

for i = 1:T+2000
                 if (i==1) 
                     simsig(i) = unvar;
                     s=(simsig(i))^0.5;
                     epsi(i) = ra(i) * s;

                   else                     
                       simsig(i) = a0+ a1*(epsi(i-1))^2;
                       s=(simsig(i))^0.5;
                       epsi(i) = ra(i)* s;
                   end
  end

epsi2 = epsi.^2;
yt = epsi2(2001:T+2000);

model = arima(1,0,0);
model.Constant = 0 ;

fit = estimate( model,yt);

    Error:

    Undefined function 'arima' for input arguments of type 'double'.

    Error in test (line 41)
    model = arima(1,0,0);

Answer 1

[Walter Roberson]

1. you might not have the econ toolbox installed
2. you might not have the econ toolbox licensed
3. you might be using a version of MATLAB older than when the arima function was first implemented
4. you might have a broken MATLAB path that does not include the econ toolbox

[dav]

Thank you very much. I s there a way to check if I have the econ toolbox?

Im using matlab 2012a

[Walter Roberson]

At the MATLAB command prompt, give the command

ver

and see if econ is listed. If it is, check license issues by using

which -all arima

arima() did exist in the Econometrics toolbox for R2012a. Additional arima functionality was added in R2012b and R2013a, but that would not affect the existence of arima() itself.