lkh 1.0.1

Super simple Python wrapper for LKH-3

PyLKH

This is a super simple Python wrapper for the constrained traveling salesman and vehicle routing problem solver called LKH-3.

If you want to use this wrapper, you should install LKH-3 first.

LKH-3 expects problems in the TSPLIB95 format. Using PyLKH you can solve problems represented as Python objects (via tsplib95) or files.

Example

import requests
import tsplib95
import lkh

problem_str = requests.get('http://vrp.galgos.inf.puc-rio.br/media/com_vrp/instances/A/A-n32-k5.vrp').text
problem = tsplib95.parse(problem_str)

solver_path = '../LKH-3.0.6/LKH'
lkh.solve(solver_path, problem=problem, runs=10)

Output:

[[26, 7, 13, 17, 19, 31, 21],
 [24, 27],
 [14, 28, 11, 4, 23, 3, 2, 6],
 [29, 18, 8, 9, 22, 15, 10, 25, 5, 20],
 [12, 1, 16, 30]]

API

lkh.solve(solver='LKH', problem=None, **kwargs)

Solve a problem.

Parameters

solver (str, optional): Path to LKH-3 executable.

problem (tsplib95.model.StandardProblem, optional): Problem object. problem or problem_file is required.

kwargs (optional): Any LKH-3 parameter described here. Lowercase works. For example: runs=10.

Returns

routes (list): List of lists of nodes.