optiwindnet.baselines.lkh
=========================

.. py:module:: optiwindnet.baselines.lkh




Module Contents
---------------

.. py:function:: lkh(A: networkx.Graph, *, capacity: int, time_limit: float, scale: float = 100000.0, vehicles: int | None = None, runs: int = 50, per_run_limit: float = 15.0, precision: int = 1000, complete: bool = False, keep_log: bool = False, seed: int | None = None) -> networkx.Graph

   Lin-Kernighan-Helsgaun via LKH-3 binary.
   Open Capacitated Vehicle Routing Problem.

   A must be normalized - use as_normalized() before calling this.

   http://akira.ruc.dk/~keld/research/LKH-3/

   :param A: graph with allowed edges (if it has 0 edges, use complete graph)
   :param capacity: maximum vehicle capacity
   :param time_limit: [s] solver run time limit
   :param scale: factor to scale lengths (should be < 1e6)
   :param vehicles: number of vehicles (if None, use the minimum feasible)
   :param runs: consult LKH manual
   :param per_run_limit: [s] consult LKH manual
   :param precision: consult LKH manual
   :param complete: make the full graph over A available (links not in A assumed direct)
   :param keep_log: save the LKH text output to graph attr 'method_log'
   :param seed: for the pseudo-random number generator (if None: random seed)

   :returns: Solution topology S


.. py:function:: iterative_lkh(Aʹ: networkx.Graph, *, capacity: int, time_limit: float, scale: float = 100000.0, vehicles: int | None = None, runs: int = 50, per_run_limit: float = 15.0, precision: int = 1000, complete: bool = False, keep_log: bool = False, seed: int | None = None, max_retries: int = 10) -> networkx.Graph

   Iterate until crossing-free solution is found (`lkh()` wrapper).

   See the docstring of lkh() for details on the LKH-3 meta-heuristic.

   The vehicle-routing solver LKH-3 may produce routes with crossings, this
   wrapper ensures the output is crossing-free. Each time a solution with a
   crossing is produced, a repair attempt is made. Failing that, one of the
   offending edges is removed from `A` and the solver is called again. In the
   same way as `lkh()`, it is recommended to pass a normalized `A`.

   :param \*: see `lkh()`
   :param max_retries: maximum number of additional calls to lkh() to avoid crossings

   :returns: Solution topology S