Simulating MA(1) process: Assertion failed

Hi all,

I am required to solve the following exercise:

Write a function that simulates an MA(1) process. The function should take the following input parameters (in this order):

• theta (MA parameter)
• sigma (standard deviation of innovations)
• epsilon0 (starting value)
• T (total length of the time series to simulate)

The result should be a Tx1 column vector.

The code to call is:

path = simulateMA1(0.9, 0.1, 0, 100)

and the function I created is:

function y = simulateMA1(theta, sigma, epsilon0, T)

y(1)=epsilon0;

for k=2:T    

      epsilon0(k)=sigma*randn; 

y(k)=epsilon0(k)+theta*epsilon0(k-1) ; 
end

y=y.'                      
end

However, after calling the function in Cody Coursework it states "Assertion failed". Since I'm obtaining the Tx1 column vector, I can't figure out the error.

I appreciate any help.

Best,

Kay