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| import numpy as np | |
| import scipy | |
| from models.solvers.lkh.lkh_base import LKHBase | |
| class LKHCVRP(LKHBase): | |
| def __init__(self, large_value=1e+6, scaling=False, max_trials=1000, seed=1234, lkh_dir="models/solvers/lkh/", io_dir="lkh_io_files"): | |
| problem = "cvrp" | |
| super().__init__(problem, large_value, scaling, max_trials, seed, lkh_dir, io_dir) | |
| def write_data(self, node_feats, f): | |
| """ | |
| Paramters | |
| --------- | |
| node_feats: dict of np.array | |
| coords: np.array [num_nodes x coord_dim] | |
| demand: np.array [num_nodes x 1] | |
| capacity: np.array [1] | |
| """ | |
| coords = node_feats["coords"] | |
| demand = node_feats["demand"] | |
| capacity = node_feats["capacity"][0] | |
| num_nodes = len(coords) | |
| if self.scaling: | |
| coords = coords * self.large_value | |
| # NOTE: In CVRP, LKH can automatically obtain optimal vehicle size. | |
| # However it cannot in CVRPTW (please check lkh_cvrptw.py). | |
| # EDGE_WEIGHT_SECTION | |
| f.write("EDGE_WEIGHT_TYPE : EUC_2D\n") | |
| # CAPACITY | |
| f.write("CAPACITY : " + str(capacity) + "\n") | |
| # NODE_COORD_SECTION | |
| f.write("NODE_COORD_SECTION\n") | |
| for i in range(num_nodes): | |
| f.write(f" {i + 1} {str(coords[i][0])[:10]} {str(coords[i][1])[:10]}\n") | |
| # DEMAND_SECTION | |
| f.write("DEMAND_SECTION\n") | |
| for i in range(num_nodes): | |
| f.write(f" {i + 1} {str(demand[i])}\n") | |
| # DEPOT SECTION | |
| f.write("DEPOT_SECTION\n") | |
| f.write("1\n") |