Forum Discussion
Lazy cut callback in Java
In Java, how can one separate cuts in a lazy manner, i.e. only separate cuts at the integer nodes? Such an approach is common in for instance a standard TSP formulation where the subtour elimination ...
Attached you can find a short example for a TSP problem that separates subtour elimination constraints lazily. There are two things you have to do
- Hook into the preintsol callback to reject integer feasible solutions that do not satisfy all the lazy cuts.
- Hook into the optnode callback to generate violated lazy cuts.
Note that you can check
if (prob.attributes().getMIPInfeas() != 0)
return;in the optnode callback to restrict separation to nodes that are integer feasible