ml4co_kit.task.routing.vrp.cvrptw

Capacitated Vehicle Routing Problem with Time Windows (CVRPTW).

CVRPTW extends CVRP by requiring every vehicle route to satisfy customer time windows and service times. Early arrivals can wait, while late arrivals are infeasible.

Note: We set the speed of each vehicle to 1.0 for simplicity. In this case, the travel time is equal to the distance.

Classes

CVRPTWTask(cvrp_open, distance_type, ...)

class ml4co_kit.task.routing.vrp.cvrptw.CVRPTWTask(cvrp_open: bool = False, distance_type: ~ml4co_kit.task.routing.base.DISTANCE_TYPE = DISTANCE_TYPE.EUC_2D, round_type: ~ml4co_kit.task.routing.base.ROUND_TYPE = ROUND_TYPE.NO, precision: ~numpy.float32 | ~numpy.float64 = <class 'numpy.float32'>, threshold: float = 0.0001)

Bases: CVRPTask

check_constraints(sol: ndarray) → bool

Check if the solution is valid.

from_data(depots: ndarray = None, points: ndarray = None, demands: ndarray = None, capacity: float = None, tw: ndarray = None, service: ndarray = None, sol: ndarray = None, ref: bool = False, normalize: bool = False, name: str = None)

Populate the task from numpy arrays.

Parameters

depotsnp.ndarray, optional

Depot coordinates, shape (2,) or (3,).

pointsnp.ndarray, optional

Customer coordinates, shape (V, 2) or (V, 3).

demandsnp.ndarray, optional

Customer demands, shape (V,).

capacityfloat, optional

Vehicle capacity.

solnp.ndarray, optional

Tour encoding with 0 depot delimiters.

refbool, optional

If True, store sol in ref_sol instead of sol.

normalizebool, optional

Scale coordinates to [0, 1] (EUC_2D only).

namestr, optional

Instance name override.

render(save_path: Path, with_sol: bool = True, figsize: tuple = (5, 5), node_color: str = 'darkblue', edge_color: str = 'darkblue', node_size: int = 50)

Save a matplotlib figure of the instance (and optional solution).

Parameters

save_pathpathlib.Path

Output image path (.png, etc.).

with_solbool, optional

Draw self.sol routes when True; instance only when False.

figsizetuple, optional

Figure size in inches.

node_color, edge_colorstr, optional

Plot colors (used when applicable).

node_sizeint, optional

Scatter marker size for customers.