lkh 1.0.2

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.

Install

pip install lkh

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.