% INVENTORY1 file inventory1.m  Generates P for (m,M) inventory policy
% Version of 1/27/97
% Data for transition probability calculations
% for (m,M) inventory policy
M  = input('Enter value M of maximum stock  ');
m  = input('Enter value m of reorder point  ');
Y  = input('Enter row vector of demand values  ');
PY = input('Enter demand probabilities  ');
states = 0:M;
ms = length(states);
my = length(Y);
% Calculations for determining P
[y,s] = meshgrid(Y,states);
T  =  max(0,M-y).*(s < m) + max(0,s-y).*(s >= m);
P  = zeros(ms,ms);
for i = 1:ms
   [a,b] = meshgrid(T(i,:),states);
   P(i,:) = PY*(a==b)';
end
disp('Result is in matrix P')