Functions
	DECLARE_int64 (cp_random_seed)
	Declaration of the core objects for the constraint solver. More...

Function Documentation

◆ DECLARE_int64()

DECLARE_int64 ( cp_random_seed )

Declaration of the core objects for the constraint solver.

The literature around constraint programming is extremely dense but one can find some basic introductions in the following links:

Here is a very simple Constraint Programming problem:

Knowing that we see 56 legs and 20 heads, how many pheasants and rabbits are we looking at?

Here is some simple Constraint Programming code to find out:

void pheasant() { Solver s("pheasant"); IntVar* const p = s.MakeIntVar(0, 20, "pheasant")); IntVar* const r = s.MakeIntVar(0, 20, "rabbit")); IntExpr* const legs = s.MakeSum(s.MakeProd(p, 2), s.MakeProd(r, 4)); IntExpr* const heads = s.MakeSum(p, r); Constraint* const ct_legs = s.MakeEquality(legs, 56); Constraint* const ct_heads = s.MakeEquality(heads, 20); s.AddConstraint(ct_legs); s.AddConstraint(ct_heads); DecisionBuilder* const db = s.MakePhase(p, r, Solver::CHOOSE_FIRST_UNBOUND, Solver::ASSIGN_MIN_VALUE); s.NewSearch(db); CHECK(s.NextSolution()); LOG(INFO) << "rabbits -> " << r->Value() << ", pheasants -> " << p->Value(); LOG(INFO) << s.DebugString(); s.EndSearch(); }

which outputs:

rabbits -> 8, pheasants -> 12 Solver(name = "pheasant", state = OUTSIDE_SEARCH, branches = 0, fails = 0, decisions = 0 propagation loops = 11, demons Run = 25, Run time = 0 ms)

C++ Reference

C++ Reference: Routing

Functions

Function Documentation

◆ DECLARE_int64()