Unable to perform assignment because the left and right sides have a different number of elements.

Hey!

I need to plot an impulse response function for a horizon of 20 periods, as a deviation of the baseline in the following terms:

• First, let yt−1 = 1 and et = 0: how does yt evolve?

• Now, let yt−1 = 1, but also et = 1 (i.e. a single shock at time t): how does yt evolve?

This is the code I came up with but I got the following error sign 'Unable to perform assignment because the left and right sides have a different number of elements.'

Can anyone help me out?

IRF_y1 = zeros(20,1);

IRF_y1(1) = c + phi+1;

for i = 2:20

IRF_y1(i) = c +phi *IRF_y1 (i-1);

end

figure(5)

plot(1:20, IRF_y1-1, '* -', 'Linewidth', 1.5)

xlabel ('horizon')

ylabel('Deviation of y_t from baseline')