Originally posted by: AmyliaZ

This may be a very simple/basic question...

I'm using CPLEX default IP solver in my program and writing part of the results (optimal objective, optimal solution, etc) in excel file, and other details on screen. I know that CPLEX generates all kinds of inequalities in its solving process, and I wonder how I can actually print out all the inequalities and if I can write these stuff (solving process) in a file as well.

Thank you.

I am not sure what you mean by "generates all kinds of inequalities" and what progress you want to display related to them. Could you please elaborate?

If you mean the constraints in the model to be solved then each API has a way to print them but they are different between the programming APIs. What programming API do you use? For an optimal solution you probably want to report the slack for each constraint?

Originally posted by: AmyliaZ

More specifically, I think the default solver uses branch and cut for most integer cases and I wonder if I can print out all the cuts added there.

I also do want to report the slack for each constraint if possible.

I'm using Concert, Java. At this point, I'm trying to print out as much detail as possible.

Thank you.

Originally posted by: T_O

Concerning the cuts, see this topic.

Reporting the slacks should be possible, I think concert useres can help you therewith.

Best regards,
Thomas

As noted in the link Thomas provided, the cuts added by CPLEX are accessible only through the C callable library, not through any of the higher level APIs (including Java).

If you want slacks for the constraints in the original model (and any cuts you might have added through callbacks), you can get them with IloCplex.getSlack (single constraint) or IloCplex.getSlacks (vector of constraints).

Paul

Originally posted by: AmyliaZ

Thank you.