Originally posted by: John85655

Hi,
is it possible and how can I implement an "or" in an if constraint
eg:

forall(s in S, t in T)
if (t mod 3 == 0)
x[s][t]+x[s]t-1 ==0
or
x[s][t]+x[s]t-2 ==0
or
x[s]t-1+x[s]t-2 ==0;

I know that there does not exist the word or in OPL, but what can i write instead?
Or does anyone has a better idea to implement this??

Many thanks for your help!!
John
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Originally posted by: SystemAdmin

How is x declared (real/integer/binary, nonnegative/unrestricted)?

It would help if you surrounded your code with {code} tags, to prevent the forum software from getting creative in its interpretation of what you are writing. It's also a good idea to check the Preview tab before posting.

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
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Originally posted by: SystemAdmin

HI,

{
...
dvar int+ xhttp://1...ihttp://1...j;
...
forall(s in S, t in T)
if (t mod 3 == 0)
x[s][t]+x[s]t-1 ==0
or
x[s][t]+x[s]t-2 ==0
or
x[s]t-1+x[s]t-2 ==0;
...
}
I hope it is more understandable now. I just want to have two of these values x[s][t],x[s]t-1 and x[s]t-2 to equal 0.

Thank you!!
John
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

HI,
...
{ dvar int+ xhttp://1...ihttp://1...j;}
...
forall(s in S, t in T)
if (t mod 3 == 0)
{x[s][t]+x[s]t-1 ==0}
or
{x[s][t]+x[s]t-2 ==0}
or
{x[s]t-1+x[s]t-2 ==0;}
...

I hope it is more understandable now. I just want to have two of these values x[s][t],x[s]t-1 and x[s]t-2 to equal 0.

Thank you!!
John
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

HI,

dvar int+ x[1...i][1...j];
...
forall(s in S, t in T)
if (t mod 3 == 0)
x[s][t]+x[s][t-1] ==0
or
x[s][t]+x[s][t-2] ==0
or
x[s]t-1+x[s][t-2] ==0;
...

I hope it is more understandable now. I just want to have two of these values x[s][t],x[s] t-1 and x[s] t-2 to equal 0.

Thank you!!
John
#CPLEXOptimizers
#DecisionOptimization

Hi

let me give you an example:

dvar int+ x[1..i][1..j];
 
subject to
{
forall(s in S, t in T)
if (t mod 3 == 0)
((x[s][t]+x[s][t-1] ==0)
||
(x[s][t]+x[s][t-2] ==0)
||
(x[s][t]-1+x[s][t-2] ==0));
}

Regards
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: John85655

Thanks a lot. It is working!
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