本文介绍了欧几里德对称的生成模型:E(n)等分反的归一化流量(E-NFS)。为了构建E-NFS,我们采用鉴别性E(n)图神经网络,并将它们集成为微分方程,以获得可逆的等式功能:连续时间归一化流量。我们展示了E-NFS在诸如DW4和LJ13的粒子系统中的文献中的基础和现有方法,以及QM9的分子在对数似然方面。据我们所知,这是第一次流动,共同生成3D中的分子特征和位置。
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这项工作引入了3D分子生成的扩散模型,该模型与欧几里得转化一样。我们的e(3)e象扩散模型(EDM)学会了通过均衡网络的扩散过程,该网络共同在连续(原子坐标)和分类特征(原子类型)上共同运行。此外,我们提供了一种概率分析,该分析使用我们的模型接受了分子的可能性计算。在实验上,所提出的方法显着优于先前关于生成样品质量和训练时效率的3D分子生成方法。
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We propose an algorithm for learning a conditional generative model of a molecule given a target. Specifically, given a receptor molecule that one wishes to bind to, the conditional model generates candidate ligand molecules that may bind to it. The distribution should be invariant to rigid body transformations that act $\textit{jointly}$ on the ligand and the receptor; it should also be invariant to permutations of either the ligand or receptor atoms. Our learning algorithm is based on a continuous normalizing flow. We establish semi-equivariance conditions on the flow which guarantee the aforementioned invariance conditions on the conditional distribution. We propose a graph neural network architecture which implements this flow, and which is designed to learn effectively despite the vast differences in size between the ligand and receptor. We evaluate our method on the CrossDocked2020 dataset, attaining a significant improvement in binding affinity over competing methods.
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Recently, studies on machine learning have focused on methods that use symmetry implicit in a specific manifold as an inductive bias. In particular, approaches using Grassmann manifolds have been found to exhibit effective performance in fields such as point cloud and image set analysis. However, there is a lack of research on the construction of general learning models to learn distributions on the Grassmann manifold. In this paper, we lay the theoretical foundations for learning distributions on the Grassmann manifold via continuous normalizing flows. Experimental results show that the proposed method can generate high-quality samples by capturing the data structure. Further, the proposed method significantly outperformed state-of-the-art methods in terms of log-likelihood or evidence lower bound. The results obtained are expected to usher in further research in this field of study.
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分子的产生,尤其是从头开始产生3D分子几何形状(即3D \ textit {de Novo} Generation)已成为药物设计中的一项基本任务。现有的基于扩散的3D分子生成方法可能会遭受性能不令人满意的性能,尤其是在产生大分子时。同时,产生的分子缺乏足够的多样性。本文提出了一个新的扩散模型,以应对这两个挑战。首先,原子关系不在分子的3D点云表示中。因此,现有生成模型很难捕获潜在的原子间力和丰富的局部约束。为了应对这一挑战,我们建议增强潜在的原子间力,并进一步涉及双重模棱两可的编码器,以编码不同强度的原子质力。其次,现有的基于扩散的模型基本上是沿数据密度梯度的几何元素。这样的过程在Langevin动力学的中间步骤中缺乏足够的探索。为了解决这个问题,我们在每个扩散/反向步骤中引入了一个分布控制变量,以实施彻底的探索并进一步改善发电多样性。对多个基准测试的广泛实验表明,所提出的模型明显优于无条件和条件生成任务的现有方法。我们还进行案例研究以帮助了解产生分子的理化特性。
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Normalizing flows provide a general mechanism for defining expressive probability distributions, only requiring the specification of a (usually simple) base distribution and a series of bijective transformations. There has been much recent work on normalizing flows, ranging from improving their expressive power to expanding their application. We believe the field has now matured and is in need of a unified perspective. In this review, we attempt to provide such a perspective by describing flows through the lens of probabilistic modeling and inference. We place special emphasis on the fundamental principles of flow design, and discuss foundational topics such as expressive power and computational trade-offs. We also broaden the conceptual framing of flows by relating them to more general probability transformations. Lastly, we summarize the use of flows for tasks such as generative modeling, approximate inference, and supervised learning.
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我们考虑一拍概率解码器,该解码器在分布上映射到集合或图形之前的矢量形状。这些功能可以集成到变分性自动化器(VAE),生成的对抗网络(GAN)或标准化流动中,并在药物发现中具有重要应用。设置和图形生成最常通过生成点(有时是边缘权重)i.i.d.从正态分布,使用变压器层或图形神经网络处理它们以及先前的向量。该架构旨在产生可交换的分布(集合的所有排列同样可能),但由于I.I.D的随机性,难以训练。一代。我们提出了一种新的对抗性定义,并表明,VAES和GAN中的交换性实际上是不必要的。然后,我们引入TOP-N,一个确定性,不可交换的集合创建机制,该创建机制学会从培训参考集中选择最相关的点。 Top-n可以替换i.i.d.在任何VAE或GaN中生成 - 它更容易训练,更好地捕获数据中的复杂依赖关系。 Top-n优于I.I.D在SetMnist重建时生成15%,生成较近合成分子数据集的真正分布的34%的集合,并且能够在经典QM9数据集上培训时产生更多样化的分子。随着一次性生成的改进基础,我们的算法有助于设计更有效的分子生成方法。
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群体模棱两可(例如,SE(3)均衡性)是科学的关键物理对称性,从经典和量子物理学到计算生物学。它可以在任意参考转换下实现强大而准确的预测。鉴于此,已经为将这种对称性编码为深神经网络而做出了巨大的努力,该网络已被证明可以提高下游任务的概括性能和数据效率。构建模棱两可的神经网络通常会带来高计算成本以确保表现力。因此,如何更好地折衷表现力和计算效率在模棱两可的深度学习模型的设计中起着核心作用。在本文中,我们提出了一个框架来构建可以有效地近似几何量的se(3)等效图神经网络。受差异几何形状和物理学的启发,我们向图形神经网络介绍了局部完整帧,因此可以将以给定订单的张量信息投射到框架上。构建本地框架以形成正常基础,以避免方向变性并确保完整性。由于框架仅是由跨产品操作构建的,因此我们的方法在计算上是有效的。我们在两个任务上评估我们的方法:牛顿力学建模和平衡分子构象的产生。广泛的实验结果表明,我们的模型在两种类型的数据集中达到了最佳或竞争性能。
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这项工作引入了离题,这是一种用于生成具有分类节点和边缘属性图的图形的离散denoising扩散模型。我们的模型定义了一个扩散过程,该过程逐步编辑了具有噪声(添加或删除边缘,更改类别)的图形以及学会恢复此过程的图形变压器网络。有了这两种成分,我们将分布学习将上的分布学习减少到一个简单的分类任务序列。我们通过提出一个新的马尔可夫噪声模型来进一步提高样品质量,该模型在扩散过程中保留节点和边缘类型的边际分布,并通过在每个扩散步骤中添加从嘈杂图中得出的辅助图理论特征。最后,我们提出了一个指导程序,以根据图形级特征调理生成。总体而言,离题可以在分子和非分子数据集上达到最新性能,在平面图数据集上,有效性提高了3倍。特别是,这是第一个模型,将鳞片缩放到包含130万个药物样分子的大型鳄梨调子数据集,而无需使用分子特异性表示,例如微笑或片段。
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分子模拟的粗粒度(CG)通过将选定的原子分组为伪珠并大幅加速模拟来简化粒子的表示。但是,这种CG程序会导致信息损失,从而使准确的背景映射,即从CG坐标恢复细粒度(FG)坐标,这是一个长期存在的挑战。受生成模型和e象网络的最新进展的启发,我们提出了一个新型模型,该模型严格嵌入了背态转换的重要概率性质和几何一致性要求。我们的模型将FG的不确定性编码为不变的潜在空间,并通过Equivariant卷积将其解码为FG几何形状。为了标准化该领域的评估,我们根据分子动力学轨迹提供了三个综合基准。实验表明,我们的方法始终恢复更现实的结构,并以显着的边距胜过现有的数据驱动方法。
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偶极矩是一个物理量,指示分子的极性,并通过反映成分原子的电性能和分子的几何特性来确定。大多数用于表示传统图神经网络方法中图表表示的嵌入方式将分子视为拓扑图,从而为识别几何信息的目标造成了重大障碍。与现有的嵌入涉及均值的嵌入不同,该嵌入适当地处理分子的3D结构不同,我们的拟议嵌入直接表达了偶极矩局部贡献的物理意义。我们表明,即使对于具有扩展几何形状的分子并捕获更多的原子相互作用信息,开发的模型甚至可以合理地工作,从而显着改善了预测结果,准确性与AB-Initio计算相当。
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包括协调性信息,例如位置,力,速度或旋转在计算物理和化学中的许多任务中是重要的。我们介绍了概括了等级图形网络的可控e(3)的等值图形神经网络(Segnns),使得节点和边缘属性不限于不变的标量,而是可以包含相协同信息,例如矢量或张量。该模型由可操纵的MLP组成,能够在消息和更新功能中包含几何和物理信息。通过可操纵节点属性的定义,MLP提供了一种新的Activation函数,以便与可转向功能字段一般使用。我们讨论我们的镜头通过等级的非线性卷曲镜头讨论我们的相关工作,进一步允许我们引脚点点的成功组件:非线性消息聚集在经典线性(可操纵)点卷积上改善;可操纵的消息在最近发送不变性消息的最近的等价图形网络上。我们展示了我们对计算物理学和化学的若干任务的方法的有效性,并提供了广泛的消融研究。
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在本文中,我们提出了多分辨率的等级图变分性Autiachoders(MGVAE),第一层级生成模型以多分辨率和等分的方式学习和生成图。在每个分辨率级别,MGVAE采用更高的顺序消息,以便在学习中对图进行编码,同时学习将其分配到互斥的集群中并赋予最终产生潜在分布的层次结构的较低分辨率。然后,MGVAE构造分层生成模型以改变地解码成粗糙的图形的层次。重要的是,我们提出的框架是关于节点排序的端到端排列等级。MGVAE通过多种生成任务实现竞争结果,包括一般图生成,分子产生,无监督的分子表示学习,以预测分子特性,引用图的链路预测,以及基于图的图像生成。
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Steerable convolutional neural networks (CNNs) provide a general framework for building neural networks equivariant to translations and other transformations belonging to an origin-preserving group $G$, such as reflections and rotations. They rely on standard convolutions with $G$-steerable kernels obtained by analytically solving the group-specific equivariance constraint imposed onto the kernel space. As the solution is tailored to a particular group $G$, the implementation of a kernel basis does not generalize to other symmetry transformations, which complicates the development of group equivariant models. We propose using implicit neural representation via multi-layer perceptrons (MLPs) to parameterize $G$-steerable kernels. The resulting framework offers a simple and flexible way to implement Steerable CNNs and generalizes to any group $G$ for which a $G$-equivariant MLP can be built. We apply our method to point cloud (ModelNet-40) and molecular data (QM9) and demonstrate a significant improvement in performance compared to standard Steerable CNNs.
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Graph neural networks have recently achieved great successes in predicting quantum mechanical properties of molecules. These models represent a molecule as a graph using only the distance between atoms (nodes). They do not, however, consider the spatial direction from one atom to another, despite directional information playing a central role in empirical potentials for molecules, e.g. in angular potentials. To alleviate this limitation we propose directional message passing, in which we embed the messages passed between atoms instead of the atoms themselves. Each message is associated with a direction in coordinate space. These directional message embeddings are rotationally equivariant since the associated directions rotate with the molecule. We propose a message passing scheme analogous to belief propagation, which uses the directional information by transforming messages based on the angle between them. Additionally, we use spherical Bessel functions and spherical harmonics to construct theoretically well-founded, orthogonal representations that achieve better performance than the currently prevalent Gaussian radial basis representations while using fewer than 1 /4 of the parameters. We leverage these innovations to construct the directional message passing neural network (DimeNet). DimeNet outperforms previous GNNs on average by 76 % on MD17 and by 31 % on QM9. Our implementation is available online. 1
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Molecular dynamics (MD) has long been the de facto choice for simulating complex atomistic systems from first principles. Recently deep learning models become a popular way to accelerate MD. Notwithstanding, existing models depend on intermediate variables such as the potential energy or force fields to update atomic positions, which requires additional computations to perform back-propagation. To waive this requirement, we propose a novel model called DiffMD by directly estimating the gradient of the log density of molecular conformations. DiffMD relies on a score-based denoising diffusion generative model that perturbs the molecular structure with a conditional noise depending on atomic accelerations and treats conformations at previous timeframes as the prior distribution for sampling. Another challenge of modeling such a conformation generation process is that a molecule is kinetic instead of static, which no prior works have strictly studied. To solve this challenge, we propose an equivariant geometric Transformer as the score function in the diffusion process to calculate corresponding gradients. It incorporates the directions and velocities of atomic motions via 3D spherical Fourier-Bessel representations. With multiple architectural improvements, we outperform state-of-the-art baselines on MD17 and isomers of C7O2H10 datasets. This work contributes to accelerating material and drug discovery.
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模棱两可的神经网络,其隐藏的特征根据G组作用于数据的表示,表现出训练效率和提高的概括性能。在这项工作中,我们将群体不变和模棱两可的表示学习扩展到无监督的深度学习领域。我们根据编码器框架提出了一种通用学习策略,其中潜在表示以不变的术语和模棱两可的组动作组件分开。关键的想法是,网络学会通过学习预测适当的小组操作来对齐输入和输出姿势以解决重建任务的适当组动作来编码和从组不变表示形式进行编码和解码数据。我们在Equivariant编码器上得出必要的条件,并提出了对任何G(离散且连续的)有效的构造。我们明确描述了我们的旋转,翻译和排列的构造。我们在采用不同网络体系结构的各种数据类型的各种实验中测试了方法的有效性和鲁棒性。
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Normalizing Flows are generative models which produce tractable distributions where both sampling and density evaluation can be efficient and exact. The goal of this survey article is to give a coherent and comprehensive review of the literature around the construction and use of Normalizing Flows for distribution learning. We aim to provide context and explanation of the models, review current state-of-the-art literature, and identify open questions and promising future directions.
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没有标签的预处理分子表示模型是各种应用的基础。常规方法主要是处理2D分子图,并仅专注于2D任务,使其预验证的模型无法表征3D几何形状,因此对于下游3D任务有缺陷。在这项工作中,我们从完整而新颖的意义上处理了3D分子预处理。特别是,我们首先提议采用基于能量的模型作为预处理的骨干,该模型具有实现3D空间对称性的优点。然后,我们为力预测开发了节点级预处理损失,在此过程中,我们进一步利用了Riemann-Gaussian分布,以确保损失为E(3) - 不变,从而实现了更多的稳健性。此外,还利用了图形噪声量表预测任务,以进一步促进最终的性能。我们评估了从两个具有挑战性的3D基准:MD17和QM9的大规模3D数据集GEOM-QM9预测的模型。实验结果支持我们方法对当前最新预处理方法的更好疗效,并验证我们设计的有效性。
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生成建模旨在揭示产生观察到的数据的潜在因素,这些数据通常可以被建模为自然对称性,这些对称性是通过不变和对某些转型定律等效的表现出来的。但是,当前代表这些对称性的方法是在需要构建模棱两可矢量场的连续正式化流中所掩盖的 - 抑制了它们在常规的高维生成建模域(如自然图像)中的简单应用。在本文中,我们专注于使用离散层建立归一化流量。首先,我们从理论上证明了对紧凑空间的紧凑型组的模棱两可的图。我们进一步介绍了三个新的品牌流:$ g $ - 剩余的流量,$ g $ - 耦合流量和$ g $ - inverse自动回旋的回旋流量,可以提升经典的残留剩余,耦合和反向自动性流量,并带有等效的地图, $。从某种意义上说,我们证明$ g $ equivariant的差异性可以通过$ g $ - $ residual流量映射,我们的$ g $ - 剩余流量也很普遍。最后,我们首次在诸如CIFAR-10之类的图像数据集中对我们的理论见解进行了补充,并显示出$ G $ equivariant有限的有限流量,从而提高了数据效率,更快的收敛性和提高的可能性估计。
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