Originally posted by: SilverOne

Hey there ! 

I'm looking to perform a conditional sum constraint based on a dvar, here's an example:

{some_tuple} set;

dvar int array[i in set];

subject to  {

   sum( i in set : array[i] > 20) i;

}

However, the code produces a decision variable (or expression) not allowed error.

Any help is appreciated, I'm a first timer on cplex.

Best Regards,

SilverOne

Hi,

you could use logical constraints.

let me share an example

{int} set={1,2,3};

dvar int array[i in set];
dvar int ourSum;
subject to  {

   ourSum==sum( i in set )  (array[i] >= 20)*i;
   array[1]==10;
   array[2]==20;
   array[3]==15;
}

execute
{
writeln("ourSum=",ourSum);
}

which gives

ourSum=2

regards

https://www.linkedin.com/pulse/o-que-%25C3%25A9-otimiza%25C3%25A7%25C3%25A3o-e-como-isso-pode-ajud%25C3%25A1-lo-fazer-mais-fleischer/

Originally posted by: SilverOne

Hey AlexFleischer,

Thank you so much you saved my life :) !! That's just was i was looking for !

ps - that linkedin link is dead.

Best Regards,

Humberto Carvalho