Aug 2026· IEEE Transactions on Visualization and Computer Graphics· Vol PP, pp. 1-15· 0 citations
Medicine
TL;DR
Three fast algorithms for reducing the time complexity of tsNET algorithm from O(nm) time to O(nlogn) time and O(n) time are presented and a comparison between these algorithms and DRGraph, another dimension reduction-based graph drawing algorithm is presented.
Abstract
The tsNET algorithm utilizes t-SNE to compute high-quality graph drawings, preserving the neighborhood and clustering structure of vertices. In this paper, we present three fast algorithms for reducing the time complexity of tsNET algorithm from O(nm) time to O(nlogn) time and O(n) time. To reduce the runtime of tsNET, there are three components that need to be reduced: (C0) computation of high-dimensional probabilities, (C1) computation of KL divergence, and (C2) entropy computation. Specifically, we integrate our new fast approaches for C0 and C2 with fast t-SNE algorithms for C1. We first present O(nlogn)-time BH-tsNET, based on (C0) new O(n)-time partial BFS-based high-dimensional probability com putation and (C2) new O(nlogn)-time quadtree-based entropy computation, integrated with (C1) O(nlogn)-time quadtree based KL divergence computation of BH-SNE. We next present faster O(nlogn)-time FIt-tsNET, using (C0) O(n)-time partial BFS-based high-dimensional probability computation and (C2) quadtree-based O(nlogn)-time entropy computation, integrated with (C1) O(n)-time interpolation-based KL divergence com putation of FIt-SNE. Finally, we present the fastest O(n) time L-tsNET, integrating (C2) new O(n)-time FFT-accelerated interpolation-based entropy computation with (C0) O(n)-time partial BFS-based high-dimensional probability computation, and (C1) O(n)-time interpolation-based KL divergence com putation of FIt-SNE. Extensive experiments using benchmark data sets confirm that BH-tsNET, FIt-tsNET, and L-tsNET outperform tsNET, running 93.5%, 96%, and 98.6% faster while computing similar quality drawings in terms of quality metrics (neighborhood preservation, stress, edge crossing, and shape-based metrics) and visual comparison. We also present a comparison between our algorithms and DRGraph, another dimension reduction-based graph drawing algorithm.
PBS is proposed and analyzed, a simple sublinear approximation algorithm for power-law graphs with parameter $\beta\in[2,3)$ that does not require any preprocessing, yet exhibits performance comparable to light index-based algorithms (of linear or sublinear index size).
In the Big Data era, the scalability of clustering algorithms constitutes a key challenge. Traditional density-based methods (e.g., DBSCAN) offer robustness to noise and the ability to detect non-linear clusters, yet their quadratic time complexity $O(N^2)$ drastically limits their applicability. Conversely, partitional algorithms (e.g., K-Means), with their linear complexity $O(N)$, impose sphericity on the resulting groups and fail in the presence of outliers. This paper presents K-SCAN -- a novel hybrid algorithm that optimizes this trade-off. The method integrates preliminary vector quantization (stochastic Mini-Batch K-Means) to extract a reduced set of weighted micro-clusters, followed by a subsequent density-based structural analysis. Empirical evaluation on datasets of up to $10^6$ samples confirms the linear computational complexity of the proposed solution. K-SCAN achieves more than a 3-fold speed-up over the hierarchical BIRCH algorithm, avoiding the costly management of tree-based structures. The method precisely identifies non-linear manifolds while maintaining structural stability (Adjusted Rand Index>0.99), even with noise levels reaching 55\% of the data volume. The main limitation of the proposed algorithm, which could not be fully eliminated in the present study, remains its susceptibility to over-smoothing and its difficulty in separating clusters with highly heterogeneous local density. In complex visual spaces, this can lead to the loss of the finest topological details.
The findings indicate that the Eppstein-Wang algorithm provides a practical and scalable solution for average distance estimation, with higher reliability on unipartite graphs compared to bipartite graphs.
The techniques introduce novel dataset decompositions, enabling chaining arguments to be applied jointly across multiple components to solve the robust k -medians problem with m outliers.
Lingxiao Huang, Zhenyu Jiang, Yi Li et al.· International Colloquium on...· 0 citations
Lloyd's $K$-means algorithm, also known as na\"{i}ve $K$-means, is a widely used ad hoc optimization heuristic, designed to minimize the sum of squared errors (SSE) across all $K$-partitions of a dataset via iterative cluster refinement. In this work, we establish a novel connection between Lloyd's algorithm and the Frank-Wolfe (FW) algorithm, a prominent first-order method for projection-free optimization. We demonstrate that Lloyd's algorithm is a special case of FW. Leveraging recent advances in FW methods for concave objectives, we derive a non-asymptotic $\mathcal{O}(1/t)$ convergence rate to a local minimum of the SSE objective. To account for empty clusters, an outcome possible under Lloyd's greedy assignment, we develop an FW variant for semismooth objectives while retaining the same convergence rate that is solely controlled by the initial SSE value. We illustrate our findings with a simulation study for spherical Gaussian mixtures and a real-world image segmentation dataset.
Michael Pokojovy, J. Jobe, Simon Lacoste-Julien· 0 citations