Question

我已经使用Google OR-Tools建模了PDPTW。

我为我的每辆车定义了一个“成本维度”，如下所示：

for vehicle_idx in range(data['n_vehicles']):
    def vehicle_cost_callback(from_index, to_index, i=vehicle_idx):
        from_node = manager.IndexToNode(from_index)
        to_node = manager.IndexToNode(to_index)
        return data['vehicle_costs'][i] * data['time_matrices'][i][from_node][to_node]
    cost_callback_index = routing.RegisterTransitCallback(vehicle_cost_callback)
    cost_callback_indices.append(cost_callback_index)
    routing.SetArcCostEvaluatorOfVehicle(cost_callback_index, vehicle_idx)

# cost dimension
cost_dimension_name = 'Cost'
routing.AddDimensionWithVehicleTransits(
    cost_callback_indices,
    0,
    max_int,
    False,
    cost_dimension_name)

现在，我想对给定车辆子集的总成本（总和）设置一个约束。有人告诉我here收集车辆费用累计变量，并对这些变量添加约束。到目前为止，我的尝试（失败）是：

total_cost = []
for i in range(data['n_vehicles']):
    if some_selection_condition:
        total_cost.append(cost_dimension.CumulVar(routing.End(i)))
routing.solver().Add(routing.solver().Sum(total_cost) <= cost_max)

这似乎是不正确的，因为即使我设置了很大的cost_max，但我肯定已经存在求解器，但求解器状态= 2（不可行）。我在做什么错了？

使用Google OR-Tools设置部分车辆的费用预算

0 个答案: