% matlab code to plot data generated by ex1.gms

% load data from ex1.dat into the matrix ex1
load ex1.dat

% use spconvert to create a matrix A, with ordinate (X axis) as first col,
% and the four abscissae as 2nd, 3rd, 4th, 5th columns.
A = spconvert(ex1);

% add the required shift to get x
x = 1990:1990+size(A,1)-1;

% make this Figure 1
figure(1);

% plot the four graphs, returning a vector of handles 
% (to which we will later assign legends)
h = plot(x,A(:,1),x,A(:,2),x,A(:,3),x,A(:,4));

% fix the ranges on the X and Y axes
axis([x(1) x(41) 0 6]);
xlabel('Time'); ylabel('A');

% make a legend, "0" allows Matlab to choose its location 
legend(h,'a','b','c','d',0);
title('Example 1: Plot of some GAMS data in Matlab');