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Record W2790000037 · doi:10.48550/arxiv.1803.02414

A gradient method in a Hilbert space with an optimized inner product: achieving a Newton-like convergence

2018· preprint· en· W2790000037 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueArXiv.org · 2018
Typepreprint
Languageen
FieldMathematics
TopicAdvanced Optimization Algorithms Research
Canadian institutionsMcMaster UniversityUniversity of Ottawa
Fundersnot available
KeywordsMathematicsLinear subspaceGradient descentHilbert spaceApplied mathematicsSubspace topologyProjection (relational algebra)Convergence (economics)Inner product spaceParameterized complexityMathematical analysisCombinatoricsAlgorithmPure mathematicsComputer science

Abstract

fetched live from OpenAlex

In this paper we introduce a new gradient method which attains quadratic convergence in a certain sense. Applicable to infinite-dimensional unconstrained minimization problems posed in a Hilbert space $H$, the approach consists in finding the energy gradient $g(λ)$ defined with respect to an optimal inner product selected from an infinite family of equivalent inner products $(\cdot,\cdot)_λ$ in the space $H$. The inner products are parameterized by a space-dependent weight function $λ$. At each iteration of the method, where an approximation to the minimizer is given by an element $u\in H$, an optimal weight $\hlambda$ is found as a solution of a nonlinear minimization problem in the space of weights $Λ$. It turns out that the projection of $κg(\hlambda)$, where $0<κ\ll 1$ is a fixed step size, onto a certain finite-dimensional subspace generated by the method is consistent with Newton's step $h$, in the sense that $P_u(κg(\hlambda))=P_u(h)$, where $P_u$ is an operator describing the projection onto the subspace. As demonstrated by rigorous analysis, this property ensures that thus constructed gradient method attains quadratic convergence for error components contained in these subspaces, in addition to the linear convergence typical of the standard gradient method. We propose a numerical implementation of this new approach and analyze its complexity. Computational results obtained based on a simple model problem confirm the theoretically established convergence properties, demonstrating that the proposed approach performs much better than the standard steepest-descent method based on Sobolev gradients. The presented results offer an explanation of a number of earlier empirical observations concerning the convergence of Sobolev-gradient methods.

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Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.002
metaresearch head score (Gemma)0.002
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.362
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0020.002
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.001
Research integrity0.0000.002
Insufficient payload (model declined to judge)0.0000.000

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 head0.090
GPT teacher head0.387
Teacher spread0.297 · 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