Hi Maria
You can’t directly use a set element as a number. Ceil(av/5) is not working, because Gams sees av as a set element (like a,b,c) and not as an integer.
One way around is using ord(av), the order of the set element.
But you still will run into problems, as you now have an equation defined over the set av and you are using the set l within the equation.
Either the equation should be defined over av AND l, or you do it this way, summing over all l where the condition after the sign is met:
\
\
\
dem(av).. z(av)- sum(l,beta(l)(ord(l) eq ceil(ord(av)/5))) =g=0
Cheers
Renger
From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Maria a. Rad
Sent: Monday, June 25, 2012 10:38 AM
To: gamsworld@googlegroups.com
Subject: equations on suffix
Dear Friends!
I want to do some algebraic operations on a suffix of a variable but I run into an error,
For example:
set l /15/
av /120/;
positive variables beta(l), z(av);
free variable w;
parameter
c(l) /1 1
2 3
3 3
4 5
5 4/;
equations
cost
dem(av);
cost… w =e= sum{l, c(l)*beta(l)};
dem(av)… z(av)-beta(ceil(av/5))=g=0;
model D /all/;
solve D using lp minimization w;
Can anyone help me?
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