java - 如何在 Apache Commons Math SimplexSolver 中设置决策变量类型，如 binary、int、double？

Question

如何在 Apache Commons Math 中设置决策变量类型，如二进制、int、double SimplexSolver ？下面程序的输出是这样的:

332.6666666666667
1.0
8331.666666666668

我希望决策变量的类型是 int 而不是 double；如果作为整数决策变量求解，输出应为 333, 0, 8325。

public static void testSample() throws OptimizationException {
    LinearObjectiveFunction f = new LinearObjectiveFunction(new double[]{25, 15}, 0);
    Collection<LinearConstraint> constraints = new ArrayList<LinearConstraint>();
    constraints.add(new LinearConstraint(new double[]{5, 8}, Relationship.LEQ, 5000));
    constraints.add(new LinearConstraint(new double[]{1, 4}, Relationship.LEQ, 1500));
    constraints.add(new LinearConstraint(new double[]{3, 2}, Relationship.LEQ, 1000));
    constraints.add(new LinearConstraint(new double[]{1, 0}, Relationship.GEQ, 1));
    constraints.add(new LinearConstraint(new double[]{0, 1}, Relationship.GEQ, 1));

    SimplexSolver solver = new SimplexSolver();
    RealPointValuePair solution = solver.optimize(f, constraints, GoalType.MAXIMIZE, true);

    System.out.println(solution.getPoint()[0]);
    System.out.println(solution.getPoint()[1]);
    System.out.println(solution.getValue());
}

Answer 1

NumberFormat 这样做很方便:

NumberFormat nf = NumberFormat.getIntegerInstance();
System.out.println(nf.format(solution.getPoint()[0]));
System.out.println(nf.format(solution.getPoint()[1]));
System.out.println(nf.format(solution.getValue()));

控制台:

33318,332

附录:此方法假定 simplex algorithm使用实数应用，结果四舍五入为整数。包含 SimplexSolver 的包裹, org.apache.commons.math.optimization.linear , 不提供其他实现。作为替代方案，请考虑 different approach或 Maxtrix<Rational> , 可用在 JScience .