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arXiv 2202.03229cs.LGcs.AI
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组合问题输出空间不变性的神经网络模型

Neural Models for Output-Space Invariance in Combinatorial Problems

Indian Institute of Technology Delhi(印度理工学院德里分校)

Yatin Nandwani, Vidit Jain, Mausam, Parag Singla

摘要:

最近,许多神经模型已经被提出来解决组合谜题,通过使用它们的解决实例隐式地学习底层约束,例如数独或图着色(GCP)。通常基于图神经网络(GNN)的所提出的架构的一个缺点是,它们不能在输出空间的大小上进行泛化,从输出空间中为变量分配值,例如,GCP中的颜色集,或数独中的板大小。我们将变量的输出空间称为“value-set”。虽然许多工作已经证明了GNN在图大小上的泛化,但还没有研究如何设计GNN来实现来自同一域的问题的值集不变性。例如,学习解决16 x 16的数独后,只有9 x 9的数独训练。在这项工作中,我们提出了新的方法来扩展基于GNN的架构,以实现值集不变性。具体来说,我们的模型建立在最近提出的循环关系网络。我们的第一种方法通过将多类节点分类问题转换为二进制节点分类问题来利用GNN的图大小不变性。我们的第二种方法通过添加多个与值集中的值对应的节点,然后根据问题的初始化将变量节点连接到值节点来直接处理多个类。我们对三个不同的组合问题的实验评估表明,我们的模型在我们的新问题上表现良好,与通用神经推理机相比。在我们的两个模型之间,我们观察到一个内在的权衡:虽然二值化模型在较小的值集上训练时提供了更好的性能,但多值模型的内存效率要高得多,从而在较大的值集上训练时提高了性能,而二值化模型无法训练。

英文摘要:

Recently many neural models have been proposed to solve combinatorial puzzles by implicitly learning underlying constraints using their solved instances, such as sudoku or graph coloring (GCP). One drawback of the proposed architectures, which are often based on Graph Neural Networks (GNN), is that they cannot generalize across the size of the output space from which variables are assigned a value, for example, set of colors in a GCP, or board-size in sudoku. We call the output space for the variables as 'value-set'. While many works have demonstrated generalization of GNNs across graph size, there has been no study on how to design a GNN for achieving value-set invariance for problems that come from the same domain. For example, learning to solve 16 x 16 sudoku after being trained on only 9 x 9 sudokus. In this work, we propose novel methods to extend GNN based architectures to achieve value-set invariance. Specifically, our model builds on recently proposed Recurrent Relational Networks. Our first approach exploits the graph-size invariance of GNNs by converting a multi-class node classification problem into a binary node classification problem. Our second approach works directly with multiple classes by adding multiple nodes corresponding to the values in the value-set, and then connecting variable nodes to value nodes depending on the problem initialization. Our experimental evaluation on three different combinatorial problems demonstrates that both our models perform well on our novel problem, compared to a generic neural reasoner. Between two of our models, we observe an inherent trade-off: while the binarized model gives better performance when trained on smaller value-sets, multi-valued model is much more memory efficient, resulting in improved performance when trained on larger value-sets, where binarized model fails to train.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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