Equal pickup and delivery constraint for every vehicle tour

[Sirine Belguith]

Hello everyone !

I'm solving the VRPTW problem with pickup and delivery.   Each vehicle is capable of doing delivery, pickup, or both at once.

     # Add Pickup and Delivery constraints.

for node_index in range(1, len(data['pickup'])):

    if data['pickup'][node_index] > 0 or data['deliveries'][node_index] > 0:

        pickup_index = manager.NodeToIndex(node_index)

        delivery_index = manager.NodeToIndex(node_index)

        # Add Pickup and Delivery constraints.

        routing.AddPickupAndDelivery(pickup_index, delivery_index)

        routing.solver().Add(routing.VehicleVar(pickup_index) == routing.VehicleVar(delivery_index))

        routing.solver().Add(time_dimension.CumulVar(pickup_index) <= time_dimension.CumulVar(delivery_index))

What is the constraint that ensures equal pickup and delivery for each trip and that every pickup has a delivery for every vehicle tour? 

Do you have any ideas to help me?

Thanks in advance

Syrine

[Sirine Belguith]

Hello, 

  Why is this constraint not working?

# Add the constraint to ensure each pickup has a delivery.
for vehicle_id in range(int(data['num_vehicles'])):
    pickup_vars = []
    delivery_vars = []
    for i in range(len(data['demands'])):
        if data['demands'][i] > 0:
            pickup_vars.append(manager.NodeToIndex(i))
        if data['deliveries'][i] > 0:
            delivery_vars.append(manager.NodeToIndex(i))
    # Ensure the number of pickups is equal to the number of deliveries
    routing.solver().Add(sum([routing.ActiveVar(pickup_var) for pickup_var in pickup_vars]) == sum([routing.ActiveVar(delivery_var) for delivery_var in delivery_vars]))

thanks