genconstr_c ++。CPP
/ *版权所有2019，Gurobi优狗万app足彩化，LLC * / / *在此示例中，我们显示了使用一般约束来建模*某些常见表达式。我们用作一个例子，我们*想要查看它是否可以满足* * l =（x0或x1或x2）和（x1或〜x2或x3）和*（x2或x3或x0）和（x3或x0或x1）和*（〜x0或x1或x2）和（〜x1或x2或x3）和*（〜x2或〜x3或x0）和（〜x3或x0或x1）* *我们通过为每个文字（本身及其*否定值）引入两个变量，每个子句的变量，然后是两个*变量来指示如果我们可以满足四个，另一个可以识别*的最小条款（所以如果它，我们可以满足所有条款）*并将这两个变量放在目标中。* i.e. the Objective function will be * * maximize Obj0 + Obj1 * * Obj0 = MIN(Clause1, ... , Clause8) * Obj1 = 1 -> Clause1 + ... + Clause8 >= 4 * * thus, the objective value will be two if and only if we can satisfy all * clauses; one if and only if at least four clauses can be satisfied, and * zero otherwise. */ #include "gurobi_c++.h" #include #include using namespace std; #define n 4 #define NLITERALS 4 // same as n #define NCLAUSES 8 #define NOBJ 2 int main(void) { GRBEnv *env = 0; try{ // Example data // e.g. {0, n+1, 2} means clause (x0 or ~x1 or x2) const int Clauses[][3] = {{ 0, n+1, 2}, { 1, n+2, 3}, { 2, n+3, 0}, { 3, n+0, 1}, {n+0, n+1, 2}, {n+1, n+2, 3}, {n+2, n+3, 0}, {n+3, n+0, 1}}; int i, status; // Create environment env = new GRBEnv("genconstr_c++.log"); // Create initial model GRBModel model = GRBModel(*env); model.set(GRB_StringAttr_ModelName, "genconstr_c++"); // Initialize decision variables and objective GRBVar Lit[NLITERALS]; GRBVar NotLit[NLITERALS]; for (i = 0; i < NLITERALS; i++) { ostringstream vname; vname << "X" << i; Lit[i] = model.addVar(0.0, 1.0, 0.0, GRB_BINARY, vname.str()); vname.str(""); vname << "notX" << i; NotLit[i] = model.addVar(0.0, 1.0, 0.0, GRB_BINARY, vname.str()); } GRBVar Cla[NCLAUSES]; for (i = 0; i < NCLAUSES; i++) { ostringstream vname; vname << "Clause" << i; Cla[i] = model.addVar(0.0, 1.0, 0.0, GRB_BINARY, vname.str()); } GRBVar Obj[NOBJ]; for (i = 0; i < NOBJ; i++) { ostringstream vname; vname << "Obj" << i; Obj[i] = model.addVar(0.0, 1.0, 1.0, GRB_BINARY, vname.str()); } // Link Xi and notXi GRBLinExpr lhs; for (i = 0; i < NLITERALS; i++) { ostringstream cname; cname << "CNSTR_X" << i; lhs = 0; lhs += Lit[i]; lhs += NotLit[i]; model.addConstr(lhs == 1.0, cname.str()); } // Link clauses and literals GRBVar clause[3]; for (i = 0; i < NCLAUSES; i++) { for (int j = 0; j < 3; j++) { if (Clauses[i][j] >= n) clause[j] = NotLit[Clauses[i][j]-n]; else clause[j] = Lit[Clauses[i][j]]; } ostringstream cname; cname << "CNSTR_Clause" << i; model.addGenConstrOr(Cla[i], clause, 3, cname.str()); } // Link objs with clauses model.addGenConstrMin(Obj[0], Cla, NCLAUSES, GRB_INFINITY, "CNSTR_Obj0"); lhs = 0; for (i = 0; i < NCLAUSES; i++) { lhs += Cla[i]; } model.addGenConstrIndicator(Obj[1], 1, lhs >= 4.0, "CNSTR_Obj1"); // Set global objective sense model.set(GRB_IntAttr_ModelSense, GRB_MAXIMIZE); // Save problem model.write("genconstr_c++.mps"); model.write("genconstr_c++.lp"); // Optimize model.optimize(); // Status checking status = model.get(GRB_IntAttr_Status); if (status == GRB_INF_OR_UNBD || status == GRB_INFEASIBLE || status == GRB_UNBOUNDED ) { cout << "The model cannot be solved " << "because it is infeasible or unbounded" << endl; return 1; } if (status != GRB_OPTIMAL) { cout << "Optimization was stopped with status " << status << endl; return 1; } // Print result double objval = model.get(GRB_DoubleAttr_ObjVal); if (objval > 1.9) cout << "Logical expression is satisfiable" << endl; else if (objval > 0.9) cout << "At least four clauses can be satisfied" << endl; else cout << "Not even three clauses can be satisfied" << endl; } catch (GRBException e) { cout << "Error code = " << e.getErrorCode() << endl; cout << e.getMessage() << endl; } catch (...) { cout << "Exception during optimization" << endl; } // Free environment delete env; return 0; }
