Initializing a binary variable

GAMS
1

Hello,

I have a problem regarding the assignment of an initial value to a binary variable in a lot sizing model.
Basically i want to assign the value 1 to the binary setup variable w for the dummyproduct k=0 in the dummy period s=0.

sets
s 	microperiods  with s=0 being a dummy period
k 	products with k=0 being a dummy product...
;

binary variables
w(k,s)	machine state indicator
...
;

I tried to search for variable initialization in GAMS and i found the following syntax used as an equation:

initialization(k)..
w('k0','s0') =e= 1;

If I use this syntax I always get the error 353:

The domain for this index position is unknown and the element cannot be checked at this point. Missing data statement.

I’m not sure how to fix it or what I’m doing wrong.

Alternatively I was wondering if it’s possible to assign an initial value like that:

initialization(k,s)$(ord (k)=0 and ord(s)=0)..
w(k,s) =e= 1;

Thanks for reading and I appreciate the help!

2

It looks like you would want to fix the variable to 1. The way to do that is w.fx(‘k0’, ‘s0’) = 1;

Hope that helps.