function op=stress2d(ii,q,a,T);

// T is an array 1 X n
// there are n calls to simulate 2017, each with T(i) days
//
// ii are the input heads in a 1 X m array. 
// recall that in ii, the first and last entries are not
// changed, i.e., they are constant head.
// q is an array the same size as iii and q(j) gives the 
// infiltration in meters per day

[ig, n]=size(T);
op=cell(n+1);

op(1).entries=ii;

for i=1:n
 deltah=simulate2d(ii,q,a,T(i));
 ii=ii+deltah; // update of heads after time T(i)
 op(i+1).entries=ii; // storing it as rows of matrix op
 disp(i);
end;

return;

