pyepo.model.copt.tsp¶

Traveling salesman problem

Attributes¶

Classes¶

`tspABModel`	COPT-backed TSP abstract base. Provides paired-variable `setObj` /
`tspGGModel`	Gavish-Graves (GG) formulation.
`tspGGModelRel`	LP relaxation of the GG formulation.
`tspDFJModel`	Danzig-Fulkerson-Johnson (DFJ) formulation with lazy subtour elimination.
`tspMTZModel`	Miller-Tucker-Zemlin (MTZ) formulation.
`tspMTZModelRel`	LP relaxation of the MTZ formulation.

Module Contents¶

class pyepo.model.copt.tsp.tspABModel(num_nodes: int, *args, **kwargs)¶

Bases: pyepo.model.bases.tspABBase, pyepo.model.copt.coptmodel.optCoptModel

COPT-backed TSP abstract base. Provides paired-variable setObj / solve / _addExtraConstr shared by GG and MTZ. DFJ overrides those.

setObj(c: numpy.ndarray | torch.Tensor | list) → None¶

A method to set the objective function

Parameters:: c – cost vector

solve() → tuple[numpy.ndarray, float]¶: A method to solve model

class pyepo.model.copt.tsp.tspGGModel(num_nodes: int, *args, **kwargs)¶

Bases: tspABModel

Gavish-Graves (GG) formulation.

relax() → tspGGModelRel¶: A method to get linear relaxation model

class pyepo.model.copt.tsp.tspGGModelRel(num_nodes: int, *args, **kwargs)¶

Bases: tspGGModel

LP relaxation of the GG formulation.

solve() → tuple[numpy.ndarray, float]¶: A method to solve model — returns fractional solution.

relax() → NoReturn¶: A forbidden method to relax MIP model

getTour(sol: numpy.ndarray | torch.Tensor | list) → list[int]¶: A forbidden method to get a tour from solution

class pyepo.model.copt.tsp.tspDFJModel(num_nodes: int, *args, **kwargs)¶

Bases: tspABModel

Danzig-Fulkerson-Johnson (DFJ) formulation with lazy subtour elimination.

Uses one undirected Var per edge, so the paired-vars setObj / solve / _addExtraConstr inherited from tspABModel are overridden here.

setObj(c: numpy.ndarray | torch.Tensor | list) → None¶

A method to set the objective function

Parameters:: c – cost vector

solve() → tuple[numpy.ndarray, float]¶: A method to solve model

class pyepo.model.copt.tsp.tspMTZModel(num_nodes: int, *args, **kwargs)¶

Bases: tspABModel

Miller-Tucker-Zemlin (MTZ) formulation.

relax() → tspMTZModelRel¶: A method to get linear relaxation model

class pyepo.model.copt.tsp.tspMTZModelRel(num_nodes: int, *args, **kwargs)¶

Bases: tspMTZModel

LP relaxation of the MTZ formulation.

solve() → tuple[numpy.ndarray, float]¶: A method to solve model — returns fractional solution.

relax() → NoReturn¶: A forbidden method to relax MIP model

getTour(sol: numpy.ndarray | torch.Tensor | list) → list[int]¶: A forbidden method to get a tour from solution

pyepo.model.copt.tsp.num_nodes = 5¶