问题
In constraint solver like Gecode , We can control the exploration of search space with help of branching function. for e.g. branch(home , x , INT_VAL_MIN ) This will start exploring the search space from the minimum possible value of variable x in its domain and try to find solution.(There are many such alternatives .)
For z3, do we have this kind of flexibility in-built ?? Any alternative possible??
回答1:
SMT solvers usually do not allow for these sorts of "hints" to be given, they act more as black-boxes.
Having said that, each solver uses a ton of internal heuristics, and z3 itself has a number of settings that you can play with to give it hints. If you run:
z3 -pd
it will display all the options you can provide, and there are literally over 600 of them! Unfortunately, these options are not really well documented, and how they impact the solver is rather cryptic. The only reliable way to find out would be to study the source code and see what they do, which isn't for the faint of heart. But in any case, it will not be as obvious as the branch feature you cite for gecode.
There are, however, other tricks one can use to speed up solving for SMT-solvers, unfortunately, these things are usually very problem-specific. If you post specific instances, you might get better suggestions.
来源：https://stackoverflow.com/questions/62035703/z3-alternative-for-gecode-branch-function