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Record W2787899424 · doi:10.1137/17m1136225

Learning Theory of Randomized Sparse Kaczmarz Method

2018· article· en· W2787899424 on OpenAlexaff
Yunwen Lei, Ding‐Xuan Zhou

Bibliographic record

VenueSIAM Journal on Imaging Sciences · 2018
Typearticle
Languageen
FieldEngineering
TopicSparse and Compressive Sensing Techniques
Canadian institutionsToronto Metropolitan University
FundersResearch Grants Council, University Grants CommitteeNational Natural Science Foundation of China
KeywordsMathematicsBregman divergenceCompressed sensingConvergence (economics)ConvexityThresholdingSequence (biology)GeneralizationCombinatoricsFunction (biology)Applied mathematicsAlgorithmDiscrete mathematicsMathematical analysisArtificial intelligenceComputer scienceImage (mathematics)

Abstract

fetched live from OpenAlex

In this paper we propose an online learning algorithm, a general randomized sparse Kaczmarz method, for generating sparse approximate solutions to linear systems and present learning theory analysis for its convergence. Under a mild assumption covering the case of noisy random measurements in the sampling process or nonlinear regression function, we show that the algorithm converges in expectation if and only if the step size sequence $\{\eta_t\}_{t\in\mathbb{N}}$ satisfies $\lim_{t\to\infty}\eta_t=0$ and $\sum_{t=1}^{\infty}\eta_t=\infty$. Convergence rates are also obtained and linear convergence is shown to be impossible under the assumption of positive variance of the sampling process. A sufficient condition for almost sure convergence is derived with an additional restriction $\sum_{t=1}^{\infty}\eta_t^2 <\infty$. Our novel analysis is performed by interpreting the randomized sparse Kaczmarz method as a special online mirror descent algorithm with a nondifferentiable mirror map and using the Bregman distance. The sufficient and necessary conditions are derived by establishing a restricted variant of strong convexity for the involved generalization error and using the special structures of the soft-thresholding operator.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.003
metaresearch head score (Gemma)0.009
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.004
Threshold uncertainty score0.015

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0030.009
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0010.001
Science and technology studies0.0010.002
Scholarly communication0.0010.002
Open science0.0020.002
Research integrity0.0020.002
Insufficient payload (model declined to judge)0.0040.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.018
GPT teacher head0.296
Teacher spread0.278 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations13
Published2018
Admission routes1
Has abstractyes

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