# 依赖: pymoo
import numpy as np
from pymoo.algorithms.moo.nsga2 import NSGA2
from pymoo.core.problem import ElementwiseProblem
from pymoo.optimize import minimize

class BiObjective(ElementwiseProblem):
    def __init__(self):
        super().__init__(n_var=2, n_obj=2, xl=np.array([0.0, 0.0]), xu=np.array([1.0, 1.0]))

    def _evaluate(self, x, out, *args, **kwargs):
        out['F'] = [x[0] ** 2 + x[1] ** 2, (x[0] - 1.0) ** 2 + (x[1] - 1.0) ** 2]

res = minimize(BiObjective(), NSGA2(pop_size=60), ('n_gen', 120), seed=1, verbose=False)
print('Pareto 前沿前 5 个点:\n', np.round(res.F[:5], 4))   # 要报告前沿而不是单个解