Originally posted by: Eliosa

Hello,

I have a tuple that I call ID and an boolean dvar called Assignement such as:

dvar boolean Assignment[ID];

dexpr float objective = 
 sum(t in ID)
    (Assignment[t]*Match_Issues[t]);

minimize objective;

My ID tuple look like:

ID = {<1,A,2,B>
    <1,A,3,C>
    <1,A,4<D>
    <5,E,6,F>
    <5,E,7,G>
};

I would like to write a constraint such as 

The assignement variable can only use the ID "1" and "5" once

I was trying to write that using All different, but it does not seem to work.

subject to {
 forall(test in ID)
    Unique: allDifferent(Assignment[test] * ID[test].LongID);

}

Thanks in advance.

Hi,

in OPL documentation you may read the example:

using CP;

int n = 5;

range R = 1..n;
dvar int x[R] in R;

subject to {
  allDifferent(all (i in R : i%2 == 0) x[i] );
  allDifferent(all (i in R : i%2 == 1) x[i] );
}

regards

https://www.linkedin.com/pulse/making-decision-optimization-simple-alex-fleischer/

Originally posted by: Eliosa

Yes I tried something like that but clearly I am writing it wrong.

Hi,

because allDifferent only works if you use CP but with CPLEX (Linear Programming) I would rewrite the tiny example into

int n = 5;

    range R = 1..n;
    dvar int x[R] in R;

    subject to {
      
      
      forall(ordered i,j in R : i%2 == 0 && j%2==0 ) x[i]!=x[j];
      forall(ordered i,j in R : i%2 == 1 && j%2==1 ) x[i]!=x[j];
    }

regards

Originally posted by: Eliosa

Thank you

I struggle with this part : 

i%2 == 0 && j%2==0

Hi,

let me decompose a bit:

int n = 5;

range R = 1..n;

{int} Reven={i | i in R:i%2 == 0};
{int} Rodd={i | i in R:i%2 == 1};

execute
{
writeln("Reven= ",Reven);
writeln("Rodd= ",Rodd);
}

dvar int x[R] in R;

subject to {
          
  forall(ordered i,j in Reven  ) x[i]!=x[j];
  forall(ordered i,j in Rodd  ) x[i]!=x[j];
}

gives

Reven=  {2 4}
Rodd=  {1 3 5}

regards

PS: See slicing https://www.ibm.com/support/knowledgecenter/en/SSSA5P_12.8.0/ilog.odms.ide.help/OPL_Studio/opllangref/topics/opl_langref_formalParams_filtering.html

Originally posted by: Eliosa

Thanks Alex, although this is useful, I don't think that will help achieving what I want to do.

In my ID tuple I have several id, I want to have a constraint that it can only use the specific id only once. Such as my assignement * id number result in an array of 0 and unique id number.

tuple IDType {
int id;
string source;
int match;
string dest; }

{IDType} ID = {<1,A,2,B>
    <1,A,3,C>
    <1,A,4<D>
    <5,E,6,F>
    <5,E,7,G>
};

Assignment can take value [1,0,0,1,0]
but can't take value [1,1,0,1,1]

Ok then can you try

.mod

tuple IDType {
int id;
string source;
int match;
string dest; }

{IDType} ID = ...;

{int} ids={i.id | i in ID};

execute
{
writeln("ids = ",ids);
}
dvar boolean x[ID];

maximize sum(i in ID) x[i];
subject to
{
forall(idOption in ids) sum(i in ID:i.id==idOption) x[i]<=1;
}

.dat

ID={<1,A,2,B>
    <1,A,3,C>
    <1,A,4,D>
    <5,E,6,F>
    <5,E,7,G>
};

?

regards