没有约束条件的VRP的OR-Tools被错误地分组

要解决没有约束条件的VRP的OR-Tools被错误地分组的问题，可以按照以下步骤进行操作：

1.导入必要的库和模块：

from ortools.constraint_solver import routing_enums_pb2
from ortools.constraint_solver import pywrapcp

2.定义创建数据模型和距离矩阵的函数：

def create_data_model():
    data = {}
    data['distance_matrix'] = [
        [0, 10, 15, 20],
        [10, 0, 35, 25],
        [15, 35, 0, 30],
        [20, 25, 30, 0]
    ]
    data['num_vehicles'] = 1
    data['depot'] = 0
    return data

3.定义解决函数：

def solve_vrp():
    # 创建数据模型
    data = create_data_model()

    # 创建路线规划器
    manager = pywrapcp.RoutingIndexManager(len(data['distance_matrix']), data['num_vehicles'], data['depot'])

    # 创建 Routing Model
    routing = pywrapcp.RoutingModel(manager)

    # 创建距离回调函数
    def distance_callback(from_index, to_index):
        # 从距离矩阵中获取距离
        return data['distance_matrix'][manager.IndexToNode(from_index)][manager.IndexToNode(to_index)]

    # 注册距离回调函数
    transit_callback_index = routing.RegisterTransitCallback(distance_callback)

    # 设置距离约束
    routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)

    # 设置搜索参数
    search_parameters = pywrapcp.DefaultRoutingSearchParameters()
    search_parameters.first_solution_strategy = (routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC)

    # 解决问题
    solution = routing.SolveWithParameters(search_parameters)

    # 输出解决方案
    if solution:
        print_solution(manager, routing, solution)

4.定义打印解决方案的函数：

def print_solution(manager, routing, solution):
    print('Objective: {} miles'.format(solution.ObjectiveValue()))
    index = routing.Start(0)
    plan_output = 'Route:\n'
    route_distance = 0
    while not routing.IsEnd(index):
        plan_output += ' {} ->'.format(manager.IndexToNode(index))
        previous_index = index
        index = solution.Value(routing.NextVar(index))
        route_distance += routing.GetArcCostForVehicle(previous_index, index, 0)
    plan_output += ' {}\n'.format(manager.IndexToNode(index))
    route_distance += routing.GetArcCostForVehicle(previous_index, index, 0)
    plan_output += 'Distance of the route: {} miles\n'.format(route_distance)
    print(plan_output)

5.调用解决函数：

if __name__ == '__main__':
    solve_vrp()

这样就能够解决没有约束条件的VRP的OR-Tools被错误地分组的问题。请注意，上述代码示例中的距离矩阵和参数仅作为演示，你需要根据实际情况进行适当的修改。