Neural message passing algorithms for semi-supervised classification on graphs have recently achieved great success. However, for classifying a node these methods only consider nodes that are a few propagation steps away and the size of this utilized neighborhood is hard to extend. In this paper, we use the relationship between graph convolutional networks (GCN) and PageRank to derive an improved propagation scheme based on personalized PageRank. We utilize this propagation procedure to construct a simple model, personalized propagation of neural predictions (PPNP), and its fast approximation, APPNP. Our model's training time is on par or faster and its number of parameters on par or lower than previous models. It leverages a large, adjustable neighborhood for classification and can be easily combined with any neural network. We show that this model outperforms several recently proposed methods for semi-supervised classification in the most thorough study done so far for GCN-like models. Our implementation is available online. 1
translated by 谷歌翻译
尽管在深度学习的其他应用领域中取得了非常深的架构,但流行的图神经网络是浅层模型。这降低了建模能力,并使模型无法捕获远程关系。浅设计的主要原因是过度平滑的,这导致节点状态随着深度的增加而变得更加相似。我们建立在GNNS和Pagerank之间的紧密联系的基础上,为此,个性化的Pagerank介绍了对个性化向量的考虑。通过这个想法,我们提出了个性化的Pagerank图神经网络(PPRGNN),该神经网络将图形卷积网络扩展到无限深度模型,该模型有机会将邻居聚集重置回每个迭代中的初始状态。我们引入了一个很好的解释调整,以重置重置并证明我们的方法与独特解决方案的收敛性,而无需放置任何限制,即使无限地进行了许多邻居聚集。与个性化的Pagerank一样,我们的结果不会过度光滑。在这样做的同时,在我们保持内存复杂性恒定的同时,时间复杂性保持线性,而与网络的深度无关,使其比较大图。我们从经验上展示了方法对各种节点和图形分类任务的有效性。在几乎所有情况下,PPRGNN优于可比较的方法。
translated by 谷歌翻译
在过去几年中,人们对代表性学习的图形神经网络(GNN)的兴趣不大。GNN提供了一个一般有效的框架,可以从图形结构化数据中学习。但是,GNN通常仅使用一个非常有限的邻域的信息来避免过度光滑。希望为模型提供更多信息。在这项工作中,我们将个性化Pagerank(PPR)的极限分布纳入图形注意力网络(GATS)中,以反映较大的邻居信息,而无需引入过度光滑。从直觉上讲,基于个性化Pagerank的消息聚合对应于无限的许多邻里聚合层。我们表明,对于四个广泛使用的基准数据集,我们的模型优于各种基线模型。我们的实施已在线公开。
translated by 谷歌翻译
Graph convolution is the core of most Graph Neural Networks (GNNs) and usually approximated by message passing between direct (one-hop) neighbors. In this work, we remove the restriction of using only the direct neighbors by introducing a powerful, yet spatially localized graph convolution: Graph diffusion convolution (GDC). GDC leverages generalized graph diffusion, examples of which are the heat kernel and personalized PageRank. It alleviates the problem of noisy and often arbitrarily defined edges in real graphs. We show that GDC is closely related to spectral-based models and thus combines the strengths of both spatial (message passing) and spectral methods. We demonstrate that replacing message passing with graph diffusion convolution consistently leads to significant performance improvements across a wide range of models on both supervised and unsupervised tasks and a variety of datasets. Furthermore, GDC is not limited to GNNs but can trivially be combined with any graph-based model or algorithm (e.g. spectral clustering) without requiring any changes to the latter or affecting its computational complexity. Our implementation is available online. 1
translated by 谷歌翻译
图形神经网络(GNNS)依赖于图形结构来定义聚合策略,其中每个节点通过与邻居的信息组合来更新其表示。已知GNN的限制是,随着层数的增加,信息被平滑,压扁并且节点嵌入式变得无法区分,对性能产生负面影响。因此,实用的GNN模型雇用了几层,只能在每个节点周围的有限邻域利用图形结构。不可避免地,实际的GNN不会根据图的全局结构捕获信息。虽然有几种研究GNNS的局限性和表达性,但是关于图形结构数据的实际应用的问题需要全局结构知识,仍然没有答案。在这项工作中,我们通过向几个GNN模型提供全球信息并观察其对下游性能的影响来认证解决这个问题。我们的研究结果表明,全球信息实际上可以为共同的图形相关任务提供显着的好处。我们进一步确定了一项新的正规化策略,导致所有考虑的任务的平均准确性提高超过5%。
translated by 谷歌翻译
Using graph neural networks for large graphs is challenging since there is no clear way of constructing mini-batches. To solve this, previous methods have relied on sampling or graph clustering. While these approaches often lead to good training convergence, they introduce significant overhead due to expensive random data accesses and perform poorly during inference. In this work we instead focus on model behavior during inference. We theoretically model batch construction via maximizing the influence score of nodes on the outputs. This formulation leads to optimal approximation of the output when we do not have knowledge of the trained model. We call the resulting method influence-based mini-batching (IBMB). IBMB accelerates inference by up to 130x compared to previous methods that reach similar accuracy. Remarkably, with adaptive optimization and the right training schedule IBMB can also substantially accelerate training, thanks to precomputed batches and consecutive memory accesses. This results in up to 18x faster training per epoch and up to 17x faster convergence per runtime compared to previous methods.
translated by 谷歌翻译
Graph convolutional networks (GCNs) are a powerful deep learning approach for graph-structured data. Recently, GCNs and subsequent variants have shown superior performance in various application areas on real-world datasets. Despite their success, most of the current GCN models are shallow, due to the over-smoothing problem.In this paper, we study the problem of designing and analyzing deep graph convolutional networks. We propose the GCNII, an extension of the vanilla GCN model with two simple yet effective techniques: Initial residual and Identity mapping. We provide theoretical and empirical evidence that the two techniques effectively relieves the problem of over-smoothing. Our experiments show that the deep GCNII model outperforms the state-of-the-art methods on various semi-and fullsupervised tasks. Code is available at https: //github.com/chennnM/GCNII.
translated by 谷歌翻译
Recent deep learning approaches for representation learning on graphs follow a neighborhood aggregation procedure. We analyze some important properties of these models, and propose a strategy to overcome those. In particular, the range of "neighboring" nodes that a node's representation draws from strongly depends on the graph structure, analogous to the spread of a random walk. To adapt to local neighborhood properties and tasks, we explore an architecture -jumping knowledge (JK) networks -that flexibly leverages, for each node, different neighborhood ranges to enable better structure-aware representation. In a number of experiments on social, bioinformatics and citation networks, we demonstrate that our model achieves state-of-the-art performance. Furthermore, combining the JK framework with models like Graph Convolutional Networks, GraphSAGE and Graph Attention Networks consistently improves those models' performance.
translated by 谷歌翻译
图形神经网络(GNNS)在学习归属图中显示了很大的力量。但是,GNNS从源节点利用遥控器的信息仍然是一个挑战。此外,常规GNN要求将图形属性作为输入,因此它们无法应用于纯图。在论文中,我们提出了名为G-GNNS(GNN的全局信息)的新模型来解决上述限制。首先,通过无监督的预训练获得每个节点的全局结构和属性特征,其保留与节点相关联的全局信息。然后,使用全局功能和原始网络属性,我们提出了一个并行GNN的并行框架来了解这些功能的不同方面。所提出的学习方法可以应用于普通图和归属图。广泛的实验表明,G-GNNS可以在三个标准评估图上优于其他最先进的模型。特别是,我们的方法在学习归属图表时建立了Cora(84.31 \%)和PubMed(80.95 \%)的新基准记录。
translated by 谷歌翻译
Graph classification is an important area in both modern research and industry. Multiple applications, especially in chemistry and novel drug discovery, encourage rapid development of machine learning models in this area. To keep up with the pace of new research, proper experimental design, fair evaluation, and independent benchmarks are essential. Design of strong baselines is an indispensable element of such works. In this thesis, we explore multiple approaches to graph classification. We focus on Graph Neural Networks (GNNs), which emerged as a de facto standard deep learning technique for graph representation learning. Classical approaches, such as graph descriptors and molecular fingerprints, are also addressed. We design fair evaluation experimental protocol and choose proper datasets collection. This allows us to perform numerous experiments and rigorously analyze modern approaches. We arrive to many conclusions, which shed new light on performance and quality of novel algorithms. We investigate application of Jumping Knowledge GNN architecture to graph classification, which proves to be an efficient tool for improving base graph neural network architectures. Multiple improvements to baseline models are also proposed and experimentally verified, which constitutes an important contribution to the field of fair model comparison.
translated by 谷歌翻译
In the last few years, graph neural networks (GNNs) have become the standard toolkit for analyzing and learning from data on graphs. This emerging field has witnessed an extensive growth of promising techniques that have been applied with success to computer science, mathematics, biology, physics and chemistry. But for any successful field to become mainstream and reliable, benchmarks must be developed to quantify progress. This led us in March 2020 to release a benchmark framework that i) comprises of a diverse collection of mathematical and real-world graphs, ii) enables fair model comparison with the same parameter budget to identify key architectures, iii) has an open-source, easy-to-use and reproducible code infrastructure, and iv) is flexible for researchers to experiment with new theoretical ideas. As of December 2022, the GitHub repository has reached 2,000 stars and 380 forks, which demonstrates the utility of the proposed open-source framework through the wide usage by the GNN community. In this paper, we present an updated version of our benchmark with a concise presentation of the aforementioned framework characteristics, an additional medium-sized molecular dataset AQSOL, similar to the popular ZINC, but with a real-world measured chemical target, and discuss how this framework can be leveraged to explore new GNN designs and insights. As a proof of value of our benchmark, we study the case of graph positional encoding (PE) in GNNs, which was introduced with this benchmark and has since spurred interest of exploring more powerful PE for Transformers and GNNs in a robust experimental setting.
translated by 谷歌翻译
图表神经网络(GNNS)在各种机器学习任务中获得了表示学习的提高。然而,应用邻域聚合的大多数现有GNN通常在图中的图表上执行不良,其中相邻的节点属于不同的类。在本文中,我们示出了在典型的异界图中,边缘可以被引导,以及是否像是处理边缘,也可以使它们过度地影响到GNN模型的性能。此外,由于异常的限制,节点对来自本地邻域之外的类似节点的消息非常有益。这些激励我们开发一个自适应地学习图表的方向性的模型,并利用潜在的长距离相关性节点之间。我们首先将图拉普拉斯概括为基于所提出的特征感知PageRank算法向数字化,该算法同时考虑节点之间的图形方向性和长距离特征相似性。然后,Digraph Laplacian定义了一个图形传播矩阵,导致一个名为{\ em diglaciangcn}的模型。基于此,我们进一步利用节点之间的通勤时间测量的节点接近度,以便在拓扑级别上保留节点的远距离相关性。具有不同级别的10个数据集的广泛实验,同意级别展示了我们在节点分类任务任务中对现有解决方案的有效性。
translated by 谷歌翻译
数据增强已广泛用于图像数据和语言数据,但仍然探索图形神经网络(GNN)。现有方法专注于从全局视角增强图表数据,并大大属于两个类型:具有特征噪声注入的结构操纵和对抗训练。但是,最近的图表数据增强方法忽略了GNNS“消息传递机制的本地信息的重要性。在这项工作中,我们介绍了本地增强,这通过其子图结构增强了节点表示的局部。具体而言,我们将数据增强模拟为特征生成过程。鉴于节点的功能,我们的本地增强方法了解其邻居功能的条件分布,并生成更多邻居功能,以提高下游任务的性能。基于本地增强,我们进一步设计了一个新颖的框架:La-GNN,可以以即插即用的方式应用于任何GNN模型。广泛的实验和分析表明,局部增强一致地对各种基准的各种GNN架构始终如一地产生性能改进。
translated by 谷歌翻译
Graph neural networks have shown significant success in the field of graph representation learning. Graph convolutions perform neighborhood aggregation and represent one of the most important graph operations. Nevertheless, one layer of these neighborhood aggregation methods only consider immediate neighbors, and the performance decreases when going deeper to enable larger receptive fields. Several recent studies attribute this performance deterioration to the over-smoothing issue, which states that repeated propagation makes node representations of different classes indistinguishable. In this work, we study this observation systematically and develop new insights towards deeper graph neural networks. First, we provide a systematical analysis on this issue and argue that the key factor compromising the performance significantly is the entanglement of representation transformation and propagation in current graph convolution operations. After decoupling these two operations, deeper graph neural networks can be used to learn graph node representations from larger receptive fields. We further provide a theoretical analysis of the above observation when building very deep models, which can serve as a rigorous and gentle description of the over-smoothing issue. Based on our theoretical and empirical analysis, we propose Deep Adaptive Graph Neural Network (DAGNN) to adaptively incorporate information from large receptive fields. A set of experiments on citation, coauthorship, and co-purchase datasets have confirmed our analysis and insights and demonstrated the superiority of our proposed methods. CCS CONCEPTS• Mathematics of computing → Graph algorithms; • Computing methodologies → Artificial intelligence; Neural networks.
translated by 谷歌翻译
灵感来自深度学习的广泛成功,已经提出了图表神经网络(GNNS)来学习表达节点表示,并在各种图形学习任务中表现出有希望的性能。然而,现有的努力主要集中在提供相对丰富的金色标记节点的传统半监督设置。虽然数据标签是难以忍受的事实令人生畏的事实并且需要强化领域知识,但特别是在考虑图形结构数据的异质性时,它通常是不切实际的。在几次半监督的环境下,大多数现有GNN的性能不可避免地受到过度装备和过天际问题的破坏,在很大程度上由于标记数据的短缺。在本文中,我们提出了一种配备有新型元学习算法的解耦的网络架构来解决这个问题。从本质上讲,我们的框架META-PN通过META学习的标签传播策略在未标记节点上乘坐高质量的伪标签,这有效增强了稀缺标记的数据,同时在培训期间启用大型接受领域。广泛的实验表明,与各种基准数据集上的现有技术相比,我们的方法提供了简单且实质性的性能。
translated by 谷歌翻译
Graph Convolutional Networks (GCNs) are powerful models for learning representations of attributed graphs. To scale GCNs to large graphs, state-of-the-art methods use various layer sampling techniques to alleviate the "neighbor explosion" problem during minibatch training. We propose GraphSAINT, a graph sampling based inductive learning method that improves training efficiency and accuracy in a fundamentally different way. By changing perspective, GraphSAINT constructs minibatches by sampling the training graph, rather than the nodes or edges across GCN layers. Each iteration, a complete GCN is built from the properly sampled subgraph. Thus, we ensure fixed number of well-connected nodes in all layers. We further propose normalization technique to eliminate bias, and sampling algorithms for variance reduction. Importantly, we can decouple the sampling from the forward and backward propagation, and extend GraphSAINT with many architecture variants (e.g., graph attention, jumping connection). GraphSAINT demonstrates superior performance in both accuracy and training time on five large graphs, and achieves new state-of-the-art F1 scores for PPI (0.995) and Reddit (0.970).
translated by 谷歌翻译
图神经网络(GNN)是非欧盟数据的强大深度学习方法。流行的GNN是通信算法(MPNNS),它们在本地图中汇总并结合了信号。但是,浅的mpnns倾向于错过远程信号,并且在某些异质图上表现不佳,而深度mpnns可能会遇到过度平滑或过度阵型等问题。为了减轻此类问题,现有的工作通常会从欧几里得数据上训练神经网络或修改图形结构中借用归一化技术。然而,这些方法在理论上并不是很好地理解,并且可能会提高整体计算复杂性。在这项工作中,我们从光谱图嵌入中汲取灵感,并提出$ \ texttt {powerembed} $ - 一种简单的层归一化技术来增强mpnns。我们显示$ \ texttt {powerembed} $可以证明图形运算符的顶部 - $ k $引导特征向量,该算子可以防止过度光滑,并且对图形拓扑是不可知的;同时,它产生了从本地功能到全球信号的表示列表,避免了过度阵列。我们将$ \ texttt {powerembed} $应用于广泛的模拟和真实图表,并展示其竞争性能,尤其是对于异性图。
translated by 谷歌翻译
消息传递已作为设计图形神经网络(GNN)的有效工具的发展。但是,消息传递的大多数现有方法简单地简单或平均所有相邻的功能更新节点表示。它们受到两个问题的限制,即(i)缺乏可解释性来识别对GNN的预测重要的节点特征,以及(ii)特征过度混合,导致捕获长期依赖和无能为力的过度平滑问题在异质或低同质的下方处理图。在本文中,我们提出了一个节点级胶囊图神经网络(NCGNN),以通过改进的消息传递方案来解决这些问题。具体而言,NCGNN表示节点为节点级胶囊组,其中每个胶囊都提取其相应节点的独特特征。对于每个节点级胶囊,开发了一个新颖的动态路由过程,以适应适当的胶囊,以从设计的图形滤波器确定的子图中聚集。 NCGNN聚集仅有利的胶囊并限制无关的消息,以避免交互节点的过度混合特征。因此,它可以缓解过度平滑的问题,并通过同粒或异质的图表学习有效的节点表示。此外,我们提出的消息传递方案本质上是可解释的,并免于复杂的事后解释,因为图形过滤器和动态路由过程确定了节点特征的子集,这对于从提取的子分类中的模型预测最为重要。关于合成和现实图形的广泛实验表明,NCGNN可以很好地解决过度光滑的问题,并为半监视的节点分类产生更好的节点表示。它的表现优于同质和异质的艺术状态。
translated by 谷歌翻译
图形神经网络已成为从图形结构数据学习的不可缺少的工具之一,并且它们的实用性已在各种各样的任务中显示。近年来,建筑设计的巨大改进,导致各种预测任务的性能更好。通常,这些神经架构在同一层中使用可知的权重矩阵组合节点特征聚合和特征转换。这使得分析从各种跳过的节点特征和神经网络层的富有效力来挑战。由于不同的图形数据集显示在特征和类标签分布中的不同级别和异常级别,因此必须了解哪些特征对于没有任何先前信息的预测任务是重要的。在这项工作中,我们将节点特征聚合步骤和深度与图形神经网络分离,并经验分析了不同的聚合特征在预测性能中发挥作用。我们表明,并非通过聚合步骤生成的所有功能都很有用,并且通常使用这些较少的信息特征可能对GNN模型的性能有害。通过我们的实验,我们表明学习这些功能的某些子集可能会导致各种数据集的性能更好。我们建议使用Softmax作为常规器,并从不同跳距的邻居聚合的功能的“软选择器”;和L2 - GNN层的标准化。结合这些技术,我们呈现了一个简单浅的模型,特征选择图神经网络(FSGNN),并经验展示所提出的模型比九个基准数据集中的最先进的GNN模型实现了可比或甚至更高的准确性节点分类任务,具有显着的改进,可达51.1%。
translated by 谷歌翻译
近三年来,异质图神经网络(HGNN)吸引了研究的兴趣。大多数现有的HGNN分为两类。一个类是基于元路径的HGNN,要么需要域知识才能手工制作元路径,要么花费大量时间和内存来自动构建元路径。另一个类不依赖元路径结构。它将均匀的卷积图神经网络(Conv-GNN)作为骨架,并通过引入节点型和边缘型依赖性参数将其扩展到异质图。不管元路径依赖性如何,大多数现有的HGNN都采用浅层探测器(例如GCN和GAT)来汇总邻里信息,并且可能有限地捕获高阶邻里信息的能力。在这项工作中,我们提出了两个异构图树网络模型:异质图树卷积网络(HETGTCN)和异质图树注意网络(HETGTAN),它们不依赖元路径来在两个节点特征和图形结构中编码异质性。在三个现实世界的异质图数据上进行了广泛的实验表明,所提出的HETGTCN和HETGTAN具有有效的效率,并且一致地超过了所有最先进的HGNN基准在半监视的节点分类任务上,并且可以深入不受损害的性能。
translated by 谷歌翻译