Optimization
Computing Approximate Graph Edit Distance via Optimal Transport
Cheng, Qihao, Yan, Da, Wu, Tianhao, Huang, Zhongyi, Zhang, Qin
Given a graph pair $(G^1, G^2)$, graph edit distance (GED) is defined as the minimum number of edit operations converting $G^1$ to $G^2$. GED is a fundamental operation widely used in many applications, but its exact computation is NP-hard, so the approximation of GED has gained a lot of attention. Data-driven learning-based methods have been found to provide superior results compared to classical approximate algorithms, but they directly fit the coupling relationship between a pair of vertices from their vertex features. We argue that while pairwise vertex features can capture the coupling cost (discrepancy) of a pair of vertices, the vertex coupling matrix should be derived from the vertex-pair cost matrix through a more well-established method that is aware of the global context of the graph pair, such as optimal transport. In this paper, we propose an ensemble approach that integrates a supervised learning-based method and an unsupervised method, both based on optimal transport. Our learning method, GEDIOT, is based on inverse optimal transport that leverages a learnable Sinkhorn algorithm to generate the coupling matrix. Our unsupervised method, GEDGW, models GED computation as a linear combination of optimal transport and its variant, Gromov-Wasserstein discrepancy, for node and edge operations, respectively, which can be solved efficiently without needing the ground truth. Our ensemble method, GEDHOT, combines GEDIOT and GEDGW to further boost the performance. Extensive experiments demonstrate that our methods significantly outperform the existing methods in terms of the performance of GED computation, edit path generation, and model generalizability.
Sparse Hierarchical Non-Linear Programming for Inverse Kinematic Planning and Control with Autonomous Goal Selection
-- Sparse programming is an important tool in robotics, for example in real-time sparse inverse kinematic control with a minimum number of active joints, or autonomous Cartesian goal selection. However, current approaches are limited to real-time control without consideration of the underlying non-linear problem. This prevents the application to non-linear problems like inverse kinematic planning while the robot simultaneously and autonomously chooses from a set of potential end-effector goal positions. Instead, kinematic reachability approximations are used while the robot's whole body motion is considered separately. This can lead to infeasible goals. Furthermore, the sparse constraints are not prioritized for intuitive problem formulation. Lastly, the computational effort of standard sparse solvers is cubically dependent on the number of constraints which prevents real-time control in the presence of a large number of possible goals. In this work, we develop a non-linear solver for sparse hierarchical non-linear programming. Sparse non-linear constraints for autonomous goal selection can be formulated on any priority level, which enables hierarchical decision making capabilities. Sparse programming is an important tool in robotics due to the inherent redundancy both in the robot's kinematics and motion planning. Robots typically possess more degrees of freedom than are necessary to fulfill a given kinematic task.
Go With the Flow: Fast Diffusion for Gaussian Mixture Models
Rapakoulias, George, Pedram, Ali Reza, Tsiotras, Panagiotis
Schr\"{o}dinger Bridges (SB) are diffusion processes that steer, in finite time, a given initial distribution to another final one while minimizing a suitable cost functional. Although various methods for computing SBs have recently been proposed in the literature, most of these approaches require computationally expensive training schemes, even for solving low-dimensional problems. In this work, we propose an analytic parametrization of a set of feasible policies for steering the distribution of a dynamical system from one Gaussian Mixture Model (GMM) to another. Instead of relying on standard non-convex optimization techniques, the optimal policy within the set can be approximated as the solution of a low-dimensional linear program whose dimension scales linearly with the number of components in each mixture. Furthermore, our method generalizes naturally to more general classes of dynamical systems such as controllable Linear Time-Varying systems that cannot currently be solved using traditional neural SB approaches. We showcase the potential of this approach in low-to-moderate dimensional problems such as image-to-image translation in the latent space of an autoencoder, and various other examples. We also benchmark our approach on an Entropic Optimal Transport (EOT) problem and show that it outperforms state-of-the-art methods in cases where the boundary distributions are mixture models while requiring virtually no training.
Towards An Unsupervised Learning Scheme for Efficiently Solving Parameterized Mixed-Integer Programs
Qu, Shiyuan, Dong, Fenglian, Wei, Zhiwei, Shang, Chao
In this paper, we describe a novel unsupervised learning scheme for accelerating the solution of a family of mixed integer programming (MIP) problems. Distinct substantially from existing learning-to-optimize methods, our proposal seeks to train an autoencoder (AE) for binary variables in an unsupervised learning fashion, using data of optimal solutions to historical instances for a parametric family of MIPs. By a deliberate design of AE architecture and exploitation of its statistical implication, we present a simple and straightforward strategy to construct a class of cutting plane constraints from the decoder parameters of an offline-trained AE. These constraints reliably enclose the optimal binary solutions of new problem instances thanks to the representation strength of the AE. More importantly, their integration into the primal MIP problem leads to a tightened MIP with the reduced feasible region, which can be resolved at decision time using off-the-shelf solvers with much higher efficiency. Our method is applied to a benchmark batch process scheduling problem formulated as a mixed integer linear programming (MILP) problem. Comprehensive results demonstrate that our approach significantly reduces the computational cost of off-the-shelf MILP solvers while retaining a high solution quality. The codes of this work are open-sourced at https://github.com/qushiyuan/AE4BV.
Sharper Error Bounds in Late Fusion Multi-view Clustering Using Eigenvalue Proportion
Du, Liang, Jiang, Henghui, Li, Xiaodong, Guo, Yiqing, Chen, Yan, Li, Feijiang, Zhou, Peng, Qian, Yuhua
Multi-view clustering (MVC) aims to integrate complementary information from multiple views to enhance clustering performance. Late Fusion Multi-View Clustering (LFMVC) has shown promise by synthesizing diverse clustering results into a unified consensus. However, current LFMVC methods struggle with noisy and redundant partitions and often fail to capture high-order correlations across views. To address these limitations, we present a novel theoretical framework for analyzing the generalization error bounds of multiple kernel $k$-means, leveraging local Rademacher complexity and principal eigenvalue proportions. Our analysis establishes a convergence rate of $\mathcal{O}(1/n)$, significantly improving upon the existing rate in the order of $\mathcal{O}(\sqrt{k/n})$. Building on this insight, we propose a low-pass graph filtering strategy within a multiple linear $k$-means framework to mitigate noise and redundancy, further refining the principal eigenvalue proportion and enhancing clustering accuracy. Experimental results on benchmark datasets confirm that our approach outperforms state-of-the-art methods in clustering performance and robustness. The related codes is available at https://github.com/csliangdu/GMLKM .
A Many Objective Problem Where Crossover is Provably Indispensable
This paper addresses theory in evolutionary multiobjective optimisation (EMO) and focuses on the role of crossover operators in many-objective optimisation. The advantages of using crossover are hardly understood and rigorous runtime analyses with crossover are lagging far behind its use in practice, specifically in the case of more than two objectives. We present a many-objective problem class together with a theoretical runtime analysis of the widely used NSGA-III to demonstrate that crossover can yield an exponential speedup on the runtime. In particular, this algorithm can find the Pareto set in expected polynomial time when using crossover while without crossover it requires exponential time to even find a single Pareto-optimal point. To our knowledge, this is the first rigorous runtime analysis in many-objective optimisation demonstrating an exponential performance gap when using crossover for more than two objectives.
Graph Neural Networks Are Evolutionary Algorithms
In this paper, we reveal the intrinsic duality between graph neural networks (GNNs) and evolutionary algorithms (EAs), bridging two traditionally distinct fields. Building on this insight, we propose Graph Neural Evolution (GNE), a novel evolutionary algorithm that models individuals as nodes in a graph and leverages designed frequency-domain filters to balance global exploration and local exploitation. Through the use of these filters, GNE aggregates high-frequency (diversity-enhancing) and low-frequency (stability-promoting) information, transforming EAs into interpretable and tunable mechanisms in the frequency domain. Extensive experiments on benchmark functions demonstrate that GNE consistently outperforms state-of-the-art algorithms such as GA, DE, CMA-ES, SDAES, and RL-SHADE, excelling in complex landscapes, optimal solution shifts, and noisy environments. Its robustness, adaptability, and superior convergence highlight its practical and theoretical value. Beyond optimization, GNE establishes a conceptual and mathematical foundation linking EAs and GNNs, offering new perspectives for both fields. Its framework encourages the development of task-adaptive filters and hybrid approaches for EAs, while its insights can inspire advances in GNNs, such as improved global information propagation and mitigation of oversmoothing. GNE's versatility extends to solving challenges in machine learning, including hyperparameter tuning and neural architecture search, as well as real-world applications in engineering and operations research. By uniting the dynamics of EAs with the structural insights of GNNs, this work provides a foundation for interdisciplinary innovation, paving the way for scalable and interpretable solutions to complex optimization problems.
TSDS: Data Selection for Task-Specific Model Finetuning
Liu, Zifan, Karbasi, Amin, Rekatsinas, Theodoros
Finetuning foundation models for specific tasks is an emerging paradigm in modern machine learning. The efficacy of task-specific finetuning largely depends on the selection of appropriate training data. We present TSDS (Task-Specific Data Selection), a framework to select data for task-specific model finetuning, guided by a small but representative set of examples from the target task. To do so, we formulate data selection for task-specific finetuning as an optimization problem with a distribution alignment loss based on optimal transport to capture the discrepancy between the selected data and the target distribution. In addition, we add a regularizer to encourage the diversity of the selected data and incorporate kernel density estimation into the regularizer to reduce the negative effects of near-duplicates among the candidate data. We connect our optimization problem to nearest neighbor search and design efficient algorithms to compute the optimal solution based on approximate nearest neighbor search techniques. We evaluate our method on data selection for both continued pretraining and instruction tuning of language models. We show that instruction tuning using data selected by our method with a 1% selection ratio often outperforms using the full dataset and beats the baseline selection methods by 1.5 points in F1 score on average. Our code is available at https://github.com/ZifanL/TSDS.
Scalable Quantum-Inspired Optimization through Dynamic Qubit Compression
Tran, Co, Tran, Quoc-Bao, Son, Hy Truong, Dinh, Thang N
Hard combinatorial optimization problems, often mapped to Ising models, promise potential solutions with quantum advantage but are constrained by limited qubit counts in near-term devices. We present an innovative quantum-inspired framework that dynamically compresses large Ising models to fit available quantum hardware of different sizes. Thus, we aim to bridge the gap between large-scale optimization and current hardware capabilities. Our method leverages a physics-inspired GNN architecture to capture complex interactions in Ising models and accurately predict alignments among neighboring spins (aka qubits) at ground states. By progressively merging such aligned spins, we can reduce the model size while preserving the underlying optimization structure. It also provides a natural trade-off between the solution quality and size reduction, meeting different hardware constraints of quantum computing devices. Extensive numerical studies on Ising instances of diverse topologies show that our method can reduce instance size at multiple levels with virtually no losses in solution quality on the latest D-wave quantum annealers.
Accelerating process control and optimization via machine learning: A review
Mitrai, Ilias, Daoutidis, Prodromos
The design and operation of chemical processes depend on An alternative approach is to accelerate the solution process decisions spanning a wide range of scales, from the molecular itself by 1) selecting a solution strategy (algorithm selection) up to the enterprise-wide, and constrained by multiple physical and 2) tuning it (algorithm configuration) such that a desired and chemical phenomena [1, 2, 3, 4]. Process control and optimization performance function like solution time is minimized. The acceleration methods provide a systematic framework to identify is usually achieved by exploiting some underlying the best possible decisions in designing and operating a process, property of the decision-making problem. An example is the subject to constraints that emerge from physics or design case of structured decision-making problems, where the structure and operational considerations. Over the last few decades, there can be used as the basis of decomposition-based optimization have been significant advances in both theory and algorithm development algorithms, which are usually faster than monolithic algorithms regarding the control of nonlinear and constrained for large-scale problems [24]. Although this approach process systems [5, 6, 7, 8, 9, 10], as well as the solution of does not compromise solution quality, selecting and tuning a broad classes of optimization problems [11, 12, 13, 14, 15].