Originally posted by: sailingyang27

Dear,

I have a question about user cut:

How many times could the user cuts be inserted at root node and other nodes?

For other nodes (not root node), can I insert user cut many times as at root node?

Many thanks,

Fan

Are you talking about user cuts from the user cut pool or cuts separated from a callback?

Originally posted by: sailingyang27

Hi Daniel,

Thanks for your reply.  I have a function of user cut (not lazy cut) separation from callback,  and I would like to know how many times I could use it at root node and non-root node.

Kind regards,

At each node (including the root node) cuts are separated in a loop: cuts are separated and the LP relaxation with cuts is resolved. This is repeated as long as new cuts are found.

So your callback will be invoked as long as new cuts are found. This implies that it will be called repeatedly as long as it adds at least one cut.

Originally posted by: sailingyang27

Hi Daniel,

Thanks for your answer. I got it. So when there is no new cut, CPLEX will begin branching?

Best wishes,

CPLEX will stop separation of cuts when your callback does not create new cuts and CPLEX does not find any more cuts on its own.

You can force CPLEX to stop separation of cuts by returning setting the useraction_p value to CPX_CALLBACK_ABORT_CUT_LOOP in a callable library application or by calling the callback's abortCutLoop() method in the other programming languages.

Originally posted by: sailingyang27

Got it! Thanks a lot!