Tree Structure for the Categorical Wasserstein Weisfeiler-Lehman Graph Kernel

Authors: Keishi Sando, Tam Le, Hideitsu Hino

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Reproducibility Variable Result LLM Response
Research Type Experimental Numerical experiments demonstrate that the performance of the proposed algorithm compares favorably with baseline kernels, while its computation is several orders of magnitude faster than the classic WWL graph kernel.
Researcher Affiliation Academia Keishi Sando EMAIL Department of Statistical Science The Graduate University for Advanced Studies Tam Le EMAIL The Institute of Statistical Mathematics Hideitsu Hino EMAIL The Institute of Statistical Mathematics / Waseda University
Pseudocode Yes Algorithm 1: Tree Structure for TWWL
Open Source Code Yes The experimental code is publicly available at https://github.com/Keishi-S/twwl.
Open Datasets Yes All datasets are downloaded from Morris et al. (2020).
Dataset Splits Yes In this experiment, we evaluate the performance of TWWL on a graph classification task using 10-fold cross-validation with a support vector machine classifier (Cortes & Vapnik, 1995).
Hardware Specification Yes All experiments are conducted on an Ubuntu 22.04 machine equipped with an Intel Xeon Gold 6354 CPU and 256GB of RAM.
Software Dependencies No The paper mentions that the method and WWL kernel are implemented in Julia and uses Python implementations for other methods, but does not provide specific version numbers for these software components or any other libraries.
Experiment Setup Yes For a regularization parameter C in the support vector classifier, we search over the range {10 3, 10 2, . . . , 103}. The number of iterations H for the WL algorithm is chosen from {1, . . . , 7}. The parameter λ of the WWL and TWWL is selected from {10 4, 10 3, . . . , 101}. For the Sinkhorn algorithm, we select the entropic regularization parameter from {0.01, 0.05, 0.1, 0.2, 0.5, 1, 10} and fix the maximum number of iterations to 1000, which is the default setting in the commonly used implementation (Flamary et al., 2021). In the second experiment, hyperparameter optimization is performed on the training data via grid search over the predetermined range of values.