Originally posted by: ToshiyukiMiyamoto

Hi

I want to solve the attached IP model using CP Optimizer, but search stops at a point.

That means time elapses but no further branch is selected.

What is the problem?

Some details:

I used OPL Studio versions 12.6.2 and 12.6.3.

The IP model can be solved using CPLEX.

I know that better equivalent CP model can be written using CP specific notations. But I want solve a CPLEX-solvable model by CP Optimizer.

Thanks,

Toshiyuki Miyamoto

Hi,

if you add

range horizon = 0..50;

and then you add this horizon to your decision variables:

dvar int+ st[Order][Job] in horizon;
dvar boolean x[Order][Job][Machine][Position];
dvar int+ ect[Order] in horizon;
dvar int+ lct[Order] in horizon;
dvar int+ TotalCD in horizon;
dvar int+ Makespan in horizon;

then CPO will find a solution in a few seconds.

Plus you could have a look at hybridation of CPO and CPLEX:

https://www.ibm.com/developerworks/community/forums/html/topic?id=72359501-c169-4215-9dc0-1c87e653b584&ps=25

regards

Originally posted by: ToshiyukiMiyamoto

Dear Alex

Thank you for your comment. Does it mean, in my case, COP was searching the next choice in huge domain

and we have to limit domain size to avoid such a situation?

Regards,

Toshiyuki Miyamoto

Hi,

limiting the domain size reduces the search space and this helps CPO a lot

regards