# Empty Matrix with Dynamic Fertility Model

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Sarah Schutz on 17 Dec 2019
Edited: Ridwan Alam on 17 Dec 2019
Hi all,
I am working on a question to replicate the simuelation portion of this code below. I have already generated the Emax matrix.
The code below is what I have. However, I am just getting a matrix full of 0's. Is there something I am doing wrong here?
simchoice = zeros(1000,20)
%Looping for 1000 women
for i = 1:1000
for t = 1:20
e = normrnd(0 , sqrt(sigma_e_sq),[1000,1])
if t == 1
N = 0
else
N = sum(simchoice(i, 1:(t-1)))
end
inc = alpha(5) + alpha(6) * t
simC_0 = inc - (p_n * N)
simC_1 = inc - (p_n * (N + 1))
simU_0 = simC_0 - (0.5*alpha(1)*simC_0*simC_0) + ((alpha(2) + e)*N) - (alpha(3)*N*N) + (alpha(4)*simC_0* N)
if t < 20
simV_0 = simU_0 + Emax((N+1), (t+1))
end
simchoice((i+1),t) = 0
if N <= 7
simU_1 = simC_1 - (0.5*alpha(1)*simC_1*simC_1) + ((alpha(2) + e)*(N+1)) - (alpha(3)*(N+1)*(N+1)) + (alpha(4)*simC_1* (N+1))
if t < 20
simV_1 = simU_1 + Emax((N+2), (t+1))
end
if simV_0 < simV_1
simchoice((i+1),t) = 1
end
end
end
end
##### 2 CommentsShowHide 1 older comment
Sarah Schutz on 17 Dec 2019
Hi! I'm sorry. simchoice is a matrix that I wanted to estimate the results of the simulation, but I am always getting a matrix full of zeros. It is supposed to represent the results of a simulation 1000 women about how many children they choose to have
If it helps this is the question I am trying to solve.

Ridwan Alam on 17 Dec 2019
Edited: Ridwan Alam on 17 Dec 2019
Looks like your indexing is off in some places:
simchoice = zeros(1000,20)
%Looping for 1000 women
for i = 1:1000
for t = 1:20
e = normrnd(0 , sqrt(sigma_e_sq),[1000,1])
if t == 1
N = 0
else
N = sum(simchoice(i, 1:(t-1)))
end
inc = alpha(5) + alpha(6) * t
simC_0 = inc - (p_n * N)
simC_1 = inc - (p_n * (N + 1))
simU_0 = simC_0 - (0.5*alpha(1)*simC_0*simC_0) + ((alpha(2) + e)*N) - (alpha(3)*N*N) + (alpha(4)*simC_0* N)
if t < 20
simV_0 = simU_0 + Emax((N), (t+1))
end
simchoice(i,t) = 0
if N <= 7
simU_1 = simC_1 - (0.5*alpha(1)*simC_1*simC_1) + ((alpha(2) + e)*(N+1)) - (alpha(3)*(N+1)*(N+1)) + (alpha(4)*simC_1* (N+1))
if t < 20
simV_1 = simU_1 + Emax((N+1), (t+1))
end
if simV_0 < simV_1
simchoice(i,t) = 1
end
end
end
end