Problem-Specific Branch-and-Bound Algorithms for the Precedence Constrained Generalized Traveling Salesman Problem

Khachay, Michael; Ukolov, Stanislav; Петунин, А. А.

doi:10.1007/978-3-030-91059-4_10

Cited by 5 publications

(1 citation statement)

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“…For example, in [25], a data-mining based approach was proposed to generate problem-specific knowledge for combinatorial optimization. In [26], Khachay et al specifically designed a B&B algorithm for the precedence-constrained generalized traveling salesman problem and demonstrated that the performance of such an algorithm is competitive against the stateof-the-art MLP-solver Gurobi. Similarly, Kudriavtsev et al proposed and refined a B&B algorithm specifically for the shortest simple path problem and demonstrated its good performance by numerical evaluations [27].…”

Section: Refined Problem-specific Branch-and-boundmentioning

confidence: 99%

Batch-Wise Permutation Feature Importance Evaluation and Problem-Specific Bigraph for Learn-to-Branch

2022

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The branch-and-bound algorithm for combinatorial optimization typically relies on a plethora of handcraft expert heuristics, and a research direction, so-called learn-to-branch, proposes to replace the expert heuristics in branch-and-bound with machine learning models. Current studies in this area typically use an imitation learning (IL) approach; however, in practice, IL often suffers from limited training samples. Thus, it has been emphasized that a small-dataset fast-training scheme for IL in learn-to-branch is worth studying, so that other methods, e.g., reinforcement learning, may be used for subsequent training. Thus, this paper focuses on the IL part of a mixed training approach, where a small-dataset fast-training scheme is considered. The contributions are as follows. First, to compute feature importance metrics so that the state-of-the-art bigraph representation can be effectively reduced for each problem type, a batch-wise permutation feature importance evaluation method is proposed, which permutes features within each batch in the forward pass. Second, based on the evaluated importance of the bigraph features, a reduced bigraph representation is proposed for each of the benchmark problems. The experimental results on four MILP benchmark problems show that our method improves branching accuracy by 8% and reduces solution time by 18% on average under the small-dataset fast-training scheme compared to the state-of-the-art bigraph-based learn-to-branch method. The source code is available online at GitHub.

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Section: Refined Problem-specific Branch-and-boundmentioning

confidence: 99%