Hi! I have a constraint (shown at the photo below) wherein two sets need to be subtracted. I tried introducing another set Kw with a definition of k-Ks but it says subtraction of element valued expressions require the set range to be equal, but the ranges domain set "Subblock" and set "Candidate_Subblocks" differ.
Identifier: Subblock
Index: k
Identifier: Candidate_Subblock
Index: Ks
Identifier: Subblock_Difference
Subset of: Subblock, Candidate_Subblocks
Index: Kw
Definition: k-Ks
above is the current code I have. Do you have any Idea on how I can code my constraint?
If Tv is input, which means it does not change depending on variables, what you can do is to introduce parameter As Tv. For example, Valid_v_t(v,t) is 1 if vessel v can load/unload at time t. then (7) can be something like
Identifier: constraint7
index domain: (k,t)
definition: gamma(k,t) = sum(v|Valid_v_t(v,t) , x(v,k))
Constraint 7:
YL(k,t) - Binary Variable(set to 1 if subblock k executes loading activity in period t)
x(v,k) - Binary variable(1 if subblock K is reserved for vessel V)
Tv - subset of period/s when vessel v loads or unloads containers
constraint 7: denotes whether a subblock performs a loading/unloading activity
care for some more explanation on the meaning of the constraint and index? otherwise, I do not know how to help here.
it’s “for which”
what does ": " mean?
Thank you! I have one last question,
how do I code constraint 7 and 9? Cause I’m not quite sure with the “:” in it. Sorry! Thank you
sum(Kw, x(v,kw))=0 will work.
you can use the index of the subset so it will only apply those elements in the subset.
Thank you so much! It worked! Now my constraint will be written
sum(Kw, x(v,k))=0
or
sum[(k|Kw, x(v,k))] = 0
?
Making both Candidate_Subblock and Subblock_Difference as a subset of Subblock and change the definition of Subblock_Difference like below should work.
Identifier: Subblock
Index: k
Identifier: Candidate_Subblock
Subset of: Subblock
Index: Ks
Identifier: Subblock_Difference
Subset of: Subblock
Index: Kw
Definition: Subblock - Candidate_Subblock
