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arxiv: 2512.22897 · v3 · submitted 2025-12-28 · 💻 cs.LG · cs.MM

Federated Multi-Task Clustering

Pith reviewed 2026-05-16 18:50 UTC · model grok-4.3

classification 💻 cs.LG cs.MM
keywords federated learningmulti-task clusteringspectral clusteringlow-rank regularizationtensor representationprivacy preservationalternating direction method of multipliers
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The pith

The FMTC framework learns personalized clustering models for heterogeneous clients by organizing them into a tensor and applying low-rank regularization to capture shared structure.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper addresses limitations in existing federated clustering approaches, which often rely on unreliable pseudo-labels and fail to model correlations among clients. FMTC introduces a client-side module that learns a parameterized mapping for robust out-of-sample inference and a server-side module that stacks client models into a tensor subject to low-rank regularization. This joint formulation is solved via a privacy-preserving ADMM algorithm that alternates between local client updates and server aggregation. Experiments on real-world datasets show consistent outperformance over baseline and state-of-the-art federated clustering methods.

Core claim

The FMTC framework learns personalized clustering models for heterogeneous clients while collaboratively leveraging their shared underlying structure in a privacy-preserving manner. Client models are organized into a unified tensor on the server, low-rank regularization is applied to discover the common subspace, and an ADMM-based distributed algorithm decomposes the optimization into parallel local updates and server aggregation.

What carries the argument

The tensorial correlation module that organizes all client models into a single tensor and applies low-rank regularization to extract their shared subspace.

If this is right

  • Personalized models can be learned without relying on pseudo-labels generated during training.
  • Shared structure across clients is explicitly modeled through the low-rank constraint on the stacked tensor.
  • The ADMM solver enables fully decentralized execution while maintaining data privacy.
  • The approach supports out-of-sample inference on new points via the learned parameterized mapping.
  • Performance gains are demonstrated across multiple real-world datasets against existing federated clustering baselines.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The tensor formulation could be replaced by other multi-view or multi-task regularizers if the low-rank assumption proves too restrictive for certain data distributions.
  • Extending the client-side mapping to deep neural networks might further improve out-of-sample generalization beyond the current linear or kernelized form.
  • The same server-side tensor construction could be applied to federated supervised tasks where clients hold related but non-identical label spaces.
  • Varying the tensor rank adaptively during training rather than fixing it in advance could reduce sensitivity to hyperparameter choice.

Load-bearing premise

Organizing client models into a single tensor and applying low-rank regularization will reliably discover meaningful shared structure across heterogeneous clients without introducing bias or requiring careful tuning of the rank parameter.

What would settle it

Running the same experiments after removing the low-rank term from the objective and observing no statistically significant drop in clustering accuracy or NMI on the reported datasets.

Figures

Figures reproduced from arXiv: 2512.22897 by Fazeng Li, Gan Sun, Qianqian Wang, Suyan Dai, Xu Tang, Yang Cong.

Figure 1
Figure 1. Figure 1: Motivation of our federated multi-task clustering model, where clients [PITH_FULL_IMAGE:figures/full_fig_p001_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: The architecture of our Federated Multi-Task Clustering (FMTC) framework, where the process begins with heterogeneous data samples [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: t-SNE visualization of the WebKB, 20Newsgroups, Reuters, and [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Convergence analysis of our proposed FMTC framework on three datasets. For each dataset, we plot the overall objective function value and the [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Parameter sensitivity analysis of FMTC on the WebKB4 dataset. The [PITH_FULL_IMAGE:figures/full_fig_p008_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Comprehensive comparison of In-Sample (IS) and Out-of-Sample (OOS) performance across all six datasets and three evaluation metrics (ACC, NMI, [PITH_FULL_IMAGE:figures/full_fig_p009_6.png] view at source ↗
read the original abstract

Spectral clustering has emerged as one of the most effective clustering algorithms due to its superior performance. However, most existing models are designed for centralized settings, rendering them inapplicable in modern decentralized environments. Moreover, current federated learning approaches often suffer from poor generalization performance due to reliance on unreliable pseudo-labels, and fail to capture the latent correlations amongst heterogeneous clients. To tackle these limitations, this paper proposes a novel framework named Federated Multi-Task Clustering (i.e.,FMTC), which intends to learn personalized clustering models for heterogeneous clients while collaboratively leveraging their shared underlying structure in a privacy-preserving manner. More specifically, the FMTC framework is composed of two main components: client-side personalized clustering module, which learns a parameterized mapping model to support robust out-of-sample inference, bypassing the need for unreliable pseudo-labels; and server-side tensorial correlation module, which explicitly captures the shared knowledge across all clients. This is achieved by organizing all client models into a unified tensor and applying a low-rank regularization to discover their common subspace. To solve this joint optimization problem, we derive an efficient, privacy-preserving distributed algorithm based on the Alternating Direction Method of Multipliers, which decomposes the global problem into parallel local updates on clients and an aggregation step on the server. To the end, several extensive experiments on multiple real-world datasets demonstrate that our proposed FMTC framework significantly outperforms various baseline and state-of-the-art federated clustering algorithms.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript proposes Federated Multi-Task Clustering (FMTC), a framework for personalized clustering in federated settings with heterogeneous clients. It features a client-side personalized clustering module that learns parameterized mapping models for robust out-of-sample inference without pseudo-labels, and a server-side tensorial correlation module that stacks client models into a tensor and applies low-rank regularization to extract shared structure. The joint optimization is solved via a privacy-preserving ADMM algorithm with local client updates and server aggregation. Experiments on real-world datasets are claimed to show significant outperformance over baselines and state-of-the-art federated clustering methods.

Significance. If the empirical superiority and the low-rank tensor mechanism hold under rigorous validation, this work could advance federated clustering by enabling personalization while collaboratively capturing latent correlations in a privacy-preserving way. The avoidance of unreliable pseudo-labels and the use of an efficient distributed ADMM solver are practical strengths. The tensor formulation offers a structured way to model multi-task correlations that may generalize to other federated multi-task problems.

major comments (2)
  1. [§3.2] §3.2 (tensorial correlation module): the low-rank regularization on the stacked client-model tensor is presented as reliably discovering shared structure, but no theorem, approximation-error bound, or heterogeneity condition is given under which the models admit a low-rank factorization without significant bias or artificial correlations. This assumption is load-bearing for the central multi-task claim.
  2. [§4] §4 (experiments): the claim of significant outperformance on real-world datasets is stated without visible details on experimental setup, exact baselines, metrics, statistical significance tests, rank-parameter selection procedure, or ADMM convergence behavior. These omissions prevent assessment of whether gains are due to the proposed mechanism or dataset-specific effects.
minor comments (1)
  1. [Abstract] Abstract: the phrase 'several extensive experiments' would benefit from naming the datasets and reporting at least one quantitative result to give readers an immediate sense of the scale of improvement.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the detailed and constructive report. We address each major comment below, indicating planned revisions to the manuscript.

read point-by-point responses
  1. Referee: [§3.2] §3.2 (tensorial correlation module): the low-rank regularization on the stacked client-model tensor is presented as reliably discovering shared structure, but no theorem, approximation-error bound, or heterogeneity condition is given under which the models admit a low-rank factorization without significant bias or artificial correlations. This assumption is load-bearing for the central multi-task claim.

    Authors: We acknowledge that the manuscript does not include a formal theorem or approximation-error bound characterizing the low-rank factorization under specific heterogeneity conditions. The low-rank assumption is motivated by standard multi-task learning literature (e.g., tensor-based MTL works) and is validated empirically through the reported performance gains. In the revision we will add a dedicated paragraph in §3.2 discussing the modeling assumption, including qualitative conditions on client heterogeneity (measured via model divergence) under which the low-rank structure is expected to hold without introducing substantial bias, together with a brief reference to related theoretical results in the MTL literature. revision: partial

  2. Referee: [§4] §4 (experiments): the claim of significant outperformance on real-world datasets is stated without visible details on experimental setup, exact baselines, metrics, statistical significance tests, rank-parameter selection procedure, or ADMM convergence behavior. These omissions prevent assessment of whether gains are due to the proposed mechanism or dataset-specific effects.

    Authors: We agree that the experimental section lacks sufficient detail for full reproducibility and assessment. In the revised manuscript we will expand §4 to include: (i) complete experimental setup (hyperparameters, data partitioning, client sampling), (ii) an explicit list of all baselines with citations, (iii) the precise evaluation metrics, (iv) results of statistical significance tests (paired t-tests with p-values), (v) the rank-parameter selection procedure (grid search over validation performance), and (vi) convergence plots and iteration counts for the ADMM solver across datasets. These additions will clarify that the observed gains stem from the proposed tensor regularization rather than implementation artifacts. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation relies on standard ADMM and empirical validation

full rationale

The FMTC framework defines client-side parameterized mapping for clustering and server-side low-rank tensor regularization on stacked client models to capture shared structure, solved via ADMM decomposition into local updates and server aggregation. No equations or steps reduce by construction to fitted inputs or self-citations; the low-rank term is introduced as an explicit modeling choice rather than defined via the target metric or prior self-work. The abstract and described components present the approach as a mechanism for personalization and correlation discovery, with performance claims resting on experiments across datasets rather than tautological reductions. This is a standard non-circular proposal of a regularized federated objective.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The framework rests on the assumption that heterogeneous client models share a low-rank common subspace that can be recovered via tensor regularization; no explicit free parameters or invented entities are detailed in the abstract, though the low-rank penalty strength is implicitly required.

free parameters (1)
  • low-rank regularization strength
    Controls the degree of shared structure enforced across client models; value not specified in abstract.
axioms (1)
  • domain assumption Heterogeneous clients share an underlying common subspace that can be captured by low-rank tensor structure.
    Invoked to justify the server-side tensorial correlation module.

pith-pipeline@v0.9.0 · 5558 in / 1299 out tokens · 18741 ms · 2026-05-16T18:50:57.866672+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

50 extracted references · 50 canonical work pages

  1. [1]

    On spectral clustering: Analysis and an algorithm,

    A. Y . Ng, M. I. Jordan, and Y . Weiss, “On spectral clustering: Analysis and an algorithm,”Adv. Neural Inf. Process. Syst. (NIPS), vol. 14, pp. 849–856, 2001

  2. [2]

    Anchor-based fast spectral ensemble clustering,

    R. Zhang, S. Hang, Z. Sun, F. Nie, R. Wang, and X. Li, “Anchor-based fast spectral ensemble clustering,”Inf. Fusion, vol. 113, p. 102587, 2025

  3. [3]

    Incremental Nyström-based multiple kernel clustering,

    Y . Feng, W. Liang, X. Wan, J. Liu, S. Liu, Q. Qu, R. Guan, H. Xu, and X. Liu, “Incremental Nyström-based multiple kernel clustering,” in Proc. AAAI Conf. Artif. Intell. (AAAI), vol. 39, no. 16, 2025, pp. 16 613– 16 621

  4. [4]

    Deep spectral clustering with projected adaptive feature selection,

    Y . Zhao, Z. Bi, P. Zhu, A. Yuan, and X. Li, “Deep spectral clustering with projected adaptive feature selection,”IEEE Trans. Geosci. Remote Sens., 2025

  5. [5]

    Spectral contrastive clustering,

    J. Williams and A. Robles-Kelly, “Spectral contrastive clustering,” Pattern Recognit., vol. 166, p. 111671, 2025

  6. [6]

    Communication-efficient learning of deep networks from decentralized data,

    B. McMahan, E. Moore, D. Ramage, S. Hampson, and B. A. y Arcas, “Communication-efficient learning of deep networks from decentralized data,” inProc. Int. Conf. Artif. Intell. Statist. (AISTATS), 2017, pp. 1273– 1282

  7. [7]

    FedX: Unsupervised federated learning with cross knowledge distillation,

    S. Han, S. Park, F. Wu, S. Kim, C. Wu, X. Xie, and M. Cha, “FedX: Unsupervised federated learning with cross knowledge distillation,” in Proc. Eur . Conf. Comput. Vision (ECCV), 2022, pp. 691–707

  8. [8]

    Unsupervised federated learning for unbalanced data,

    M. Servetnyk, C. C. Fung, and Z. Han, “Unsupervised federated learning for unbalanced data,” inProc. IEEE Global Commun. Conf. (GLOBECOM). IEEE, 2020, pp. 1–6

  9. [9]

    Federated K-means cluster- ing: A novel edge AI based approach for privacy preservation,

    H. H. Kumar, V . Karthik, and M. K. Nair, “Federated K-means cluster- ing: A novel edge AI based approach for privacy preservation,” inProc. IEEE Int. Conf. Cloud Comput. Emerg. Markets (CCEM). IEEE, 2020, pp. 52–56

  10. [10]

    Federated K-means clustering,

    S. Garst and M. Reinders, “Federated K-means clustering,” inProc. Int. Conf. Pattern Recognit. (ICPR). Springer, 2024, pp. 107–122

  11. [11]

    Federated spectral clustering via secure similarity reconstruction,

    D. Qiao, C. Ding, and J. Fan, “Federated spectral clustering via secure similarity reconstruction,”Adv. Neural Inf. Process. Syst. (NeurIPS), vol. 36, pp. 58 520–58 555, 2023

  12. [12]

    Towards personalized federated learning,

    A. Z. Tan, H. Yu, L. Cui, and Q. Yang, “Towards personalized federated learning,”IEEE Trans. Neural Netw. Learn. Syst., vol. 34, no. 12, pp. 9587–9603, 2023

  13. [13]

    Adaptive personalized federated learning,

    Y . Deng, M. M. Kamani, and M. Mahdavi, “Adaptive personalized federated learning,”arXiv preprint arXiv:2003.13461, 2020

  14. [14]

    Consistent graph learning for multi-view spectral clustering,

    D. Xie, Q. Gao, Y . Zhao, F. Yang, and W. Song, “Consistent graph learning for multi-view spectral clustering,”Pattern Recognit., vol. 154, p. 110598, 2024

  15. [15]

    EPLSC: A new semi-supervised ensemble spectral clustering algorithm based on the graph P-laplacian for genetic data,

    V . Garcia and A. Sanchez, “EPLSC: A new semi-supervised ensemble spectral clustering algorithm based on the graph P-laplacian for genetic data,”Adv. Eng. Intell. Syst., vol. 4, no. 01, pp. 102–113, 2025

  16. [16]

    Enhancing generalized spectral clustering with embedding laplacian graph regular- ization,

    H. Zhang, J. Yang, B. Zhang, Y . Tang, W. Du, and B. Wen, “Enhancing generalized spectral clustering with embedding laplacian graph regular- ization,”CAAI Trans. Intell. Technol., 2024

  17. [17]

    Two-pronged feature reduction in spectral clustering with optimized landmark selection,

    A. Rouhi, A. Bouyer, B. Arasteh, and X. Liu, “Two-pronged feature reduction in spectral clustering with optimized landmark selection,” Appl. Soft Comput., vol. 161, p. 111775, 2024

  18. [18]

    Deep spectral clustering via joint spectral embed- ding and K-means,

    W. Guo and W. Ye, “Deep spectral clustering via joint spectral embed- ding and K-means,” inProc. IEEE Int. Conf. Syst. Man Cybern. (SMC). IEEE, 2024, pp. 3293–3299

  19. [19]

    Federated clustering and semi-supervised learning: A new partnership for personalized human activity recognition,

    R. Presotto, G. Civitarese, and C. Bettini, “Federated clustering and semi-supervised learning: A new partnership for personalized human activity recognition,”Pervasive Mobile Comput., vol. 88, p. 101726, 2023

  20. [20]

    Federated learning with soft cluster- ing,

    C. Li, G. Li, and P. K. Varshney, “Federated learning with soft cluster- ing,”IEEE Internet Things J., vol. 9, no. 10, pp. 7773–7782, 2022

  21. [21]

    An efficient framework for clustered federated learning,

    A. Ghosh, J. Chung, D. Yin, and K. Ramchandran, “An efficient framework for clustered federated learning,”IEEE Trans. Inf. Theory, vol. 68, no. 12, pp. 8076–8091, 2022

  22. [22]

    Clustered federated learning: Model-agnostic distributed multitask optimization under privacy con- straints,

    F. Sattler, K.-R. Müller, and W. Samek, “Clustered federated learning: Model-agnostic distributed multitask optimization under privacy con- straints,”IEEE Trans. Neural Netw. Learn. Syst., vol. 32, no. 8, pp. 3710–3722, 2021

  23. [23]

    LCFed: An efficient clustered federated learning framework for heterogeneous data,

    Y . Zhang, H. Chen, Z. Lin, Z. Chen, and J. Zhao, “LCFed: An efficient clustered federated learning framework for heterogeneous data,” inProc. IEEE Int. Conf. Acoust., Speech Signal Process. (ICASSP). IEEE, 2025, pp. 1–5

  24. [24]

    Asynchronous federated clustering with unknown number of clusters,

    Y . Zhang, Y . Zhang, Y . Lu, M. Li, X. Chen, and Y .-m. Cheung, “Asynchronous federated clustering with unknown number of clusters,” arXiv preprint arXiv:2412.20341, 2024

  25. [25]

    Federated K-means clus- tering via dual decomposition-based distributed optimization,

    V . Yfantis, A. Wagner, and M. Ruskowski, “Federated K-means clus- tering via dual decomposition-based distributed optimization,”Franklin Open, vol. 10, p. 100204, 2025

  26. [26]

    Efficient federated multi-view clustering with integrated matrix factorization and K-means,

    W. Feng, Z. Wu, Q. Wang, B. Dong, Z. Tao, and Q. Gao, “Efficient federated multi-view clustering with integrated matrix factorization and K-means,” inProc. Int. Joint Conf. Artif. Intell. (IJCAI), 2024, pp. 439– 447

  27. [27]

    A survey on multi-task learning,

    Y . Zhang and Q. Yang, “A survey on multi-task learning,”IEEE Trans. Knowl. Data Eng., vol. 34, no. 12, pp. 5586–5609, 2022

  28. [28]

    Cross-silo federated learning: Chal- lenges and opportunities,

    C. Huang, J. Huang, and X. Liu, “Cross-silo federated learning: Chal- lenges and opportunities,”arXiv preprint arXiv:2206.12949, 2022

  29. [29]

    Personalized cross-silo federated learning on non-iid data,

    Y . Huang, L. Chu, Z. Zhou, L. Wang, J. Liu, J. Pei, and Y . Zhang, “Personalized cross-silo federated learning on non-iid data,” inProc. AAAI Conf. Artif. Intell. (AAAI), vol. 35, no. 9, 2021, pp. 7865–7873

  30. [30]

    Structural deep incomplete multi-view clustering network,

    J. Wen, Z. Wu, Z. Zhang, L. Fei, B. Zhang, and Y . Xu, “Structural deep incomplete multi-view clustering network,” inProc. 30th ACM Int. Conf. Inf. Knowl. Manage. (CIKM). New York, NY , USA: ACM, 2021, pp. 3538–3542

  31. [31]

    Deep incomplete multi-view clustering via mining cluster complementarity,

    J. Xu, C. Li, Y . Ren, L. Peng, Y . Mo, X. Shi, and X. Zhu, “Deep incomplete multi-view clustering via mining cluster complementarity,” inProc. AAAI Conf. Artif. Intell. (AAAI), vol. 36, no. 8, 2022, pp. 8761– 8769

  32. [32]

    Incomplete multiview spectral clustering with adaptive graph learning,

    J. Wen, Y . Xu, and H. Liu, “Incomplete multiview spectral clustering with adaptive graph learning,”IEEE Trans. Cybern., vol. 50, no. 4, pp. 1418–1429, 2020. JOURNAL OF LATEX CLASS FILES, VOL. 14, NO. 8, AUGUST 2021 11

  33. [33]

    Consensus guided incomplete multi-view spectral clustering,

    J. Wen, H. Sun, L. Fei, J. Li, Z. Zhang, and B. Zhang, “Consensus guided incomplete multi-view spectral clustering,”Neural Netw., vol. 133, pp. 207–219, 2021

  34. [34]

    Unified tensor framework for incomplete multi-view clustering and missing-view inferring,

    J. Wen, Z. Zhang, Z. Zhang, L. Zhu, L. Fei, B. Zhang, and Y . Xu, “Unified tensor framework for incomplete multi-view clustering and missing-view inferring,” inProc. AAAI Conf. Artif. Intell. (AAAI), vol. 35, no. 11, 2021, pp. 10 273–10 281

  35. [35]

    Tensor robust principal component analysis with a new tensor nuclear norm,

    C. Lu, J. Feng, Y . Chen, W. Liu, Z. Lin, and S. Yan, “Tensor robust principal component analysis with a new tensor nuclear norm,”IEEE Trans. Pattern Anal. Mach. Intell., vol. 42, no. 4, pp. 925–938, 2020

  36. [36]

    Multitask Bregman clustering,

    J. Zhang and C. Zhang, “Multitask Bregman clustering,”Neurocomput- ing, vol. 74, no. 10, pp. 1720–1734, 2011

  37. [37]

    Smart multitask Bregman clustering and multitask kernel clustering,

    X. Zhang, X. Zhang, and H. Liu, “Smart multitask Bregman clustering and multitask kernel clustering,”ACM Trans. Knowl. Discov. Data, vol. 10, no. 1, pp. 1–29, 2015

  38. [38]

    Multitask spectral clustering by exploring intertask correlation,

    Y . Yang, Z. Ma, Y . Yang, F. Nie, and H. T. Shen, “Multitask spectral clustering by exploring intertask correlation,”IEEE Trans. Cybern., vol. 45, no. 5, pp. 1083–1094, 2015

  39. [39]

    Scalable federated one-step multi-view clustering with tensorized regularization,

    W. Feng, D. Liu, Q. Wang, W. Liang, and Z. Yan, “Scalable federated one-step multi-view clustering with tensorized regularization,” inProc. AAAI Conf. Artif. Intell. (AAAI), vol. 39, no. 16, 2025, pp. 16 586– 16 594

  40. [40]

    FedSpectral+: Spectral clustering using federated learning,

    J. Thakkar and D. Joshi, “FedSpectral+: Spectral clustering using federated learning,”arXiv preprint arXiv:2302.02137, 2023

  41. [41]

    C. D. Manning,Introduction to information retrieval. Syngress Publishing„ 2008

  42. [42]

    Global convergence of ADMM in nonconvex nonsmooth optimization,

    Y . Wang, W. Yin, and J. Zeng, “Global convergence of ADMM in nonconvex nonsmooth optimization,”J. Sci. Comput., vol. 78, no. 1, pp. 29–63, 2019. APPENDIX In this section, we provide the convergence analysis for Algorithm 1. The overall problem is non-convex due to the orthogonality constraintF T t Ft =Iand potentially the tensor regularizer∥W∥ p Sp (forp...

  43. [43]

    ,Wm,F 1,

    Reformulation as a Two-Block Problem The original problem can be cast as a two-block constrained optimization problem: min X1,X2 G(X1) +H(X 2)s.t.AX 1 +BX 2 = 0,(21) where the blocks are defined as: •Block 1:X 1 = (W 1, . . . ,Wm,F 1, . . . ,Fm). •Block 2:X 2 =Z. •Block 1 Objective:G(X 1) = Pm t=1 ft(Wt,F t), which is non-convex. •Block 2 Objective:H(X 2)...

  44. [44]

    These results typically show that if the algorithm’s parameters are chosen correctly, the sequence of iterates converges to a stationary point

    Invoking Standard ADMM Convergence Theory The convergence of ADMM for two-block non-convex optimization problems is well-established in the literature (e.g., Wang, Yin, and Zeng, 2019). These results typically show that if the algorithm’s parameters are chosen correctly, the sequence of iterates converges to a stationary point. The key requirements for th...

  45. [45]

    The objective function is bounded from below (Assump- tion A1)

  46. [46]

    The smooth parts of the objective have Lipschitz con- tinuous gradients (Assumption A2’)

  47. [47]

    In our case: •TheW t-subproblem is solved exactly

    The subproblems for each block are solved to a sufficient degree of accuracy. In our case: •TheW t-subproblem is solved exactly. Its objective is strongly convex with modulusρdue to the penalty term, which guarantees a sufficient decrease of at least ρ 2 ∥Wk+1 t −W k t ∥2 F . •TheF t-subproblem satisfies the sufficient decrease condition (Assumption A3’)....

  48. [48]

    The spe- cific condition is typically of the formρ > cL f for some constantc, ensuring that the quadratic penalty dominates any potential increase caused by non-convexity

    The penalty parameterρis sufficiently large. The spe- cific condition is typically of the formρ > cL f for some constantc, ensuring that the quadratic penalty dominates any potential increase caused by non-convexity. Under these conditions, it can be proven that a carefully con- structed Lyapunov function (often involvingL ρ and proximal terms related to ...

  49. [49]

    •Primal Feasibility: The dual update rule isY k+1 t −Yk t = ρ(Wk+1 t −Z k+1 t )

    Verifying KKT Conditions at the Limit Point The convergence of consecutive iterates allows us to estab- lish the KKT conditions at any limit point(W ∗,F ∗,Z ∗,Y ∗). •Primal Feasibility: The dual update rule isY k+1 t −Yk t = ρ(Wk+1 t −Z k+1 t ). Since the sequence of iterates is bounded and the difference between consecutive iterates goes to zero, it can ...

  50. [50]

    He was an Associate Professor with the State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, until 2024. He has authored papers in top-tier conferences such as CVPR, ICCV , ECCV , AAAI, IJCAI, and ICDM, as well as top-tier journals including TPAMI, TNNLS, TIP, TMM, TCSVT, and Pattern Recognition. His current rese...