$title Example: Redoing Fibonacci example (cond2.gms)
$stitle Using conditional assignments and ORD

$onuellist
option limcol=0, solprint = off;

set I / A, B, 1*20 /;

variable x(I), dummy_cost;

equation
	fibonacci(I)
	objective;

fibonacci(I)..
	x(I) =e= (x(I-1)+x(I-2))$(ord(I) > 2) + 1$(ord(I) <= 2);

objective..
	dummy_cost =e= 0;

model fib1 /all/;

solve fib1 using lp minimizing dummy_cost;

display x.l;


$stitle Using conditional assignments and sameas

equation fibonacci2(I), fibonacci3(I);

fibonacci2(I)..
	x(I) =e= (x(I-1)+x(I-2))$(ord(I) > 2) + 
	     1$(sameas(I,"A") or sameas(I,"B"));

model fib2 /objective,fibonacci2/;

solve fib2 using lp minimizing dummy_cost;

display x.l;


$stitle Using conditional assignments and set membership

set J(I) / 1*20 /;

fibonacci3(I)..
	x(I) =e= (x(I-1)+x(I-2))$J(I) + 1$(not J(I));

model fib3 /objective,fibonacci3/;

solve fib3 using lp minimizing dummy_cost;

display x.l;