% 1.731 Irrigation rainfall-streamflow example
function AR
% load rainfall sequence
load precip.dat;
n=length(precip)
q(1)=1
% for loop steps through precipitation 
for t=1:n
    q(t+1)=0.8*q(t)+0.2*precip(t);
end
q
close all
figure
subplot(2,1,1)
bar(0.5:n-0.5,precip,1)
axis([0 20 0 3])
subplot(2,1,2)
plot(0:n,q)
axis([0 20 0 2])
return