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Record W4394761142 · doi:10.1137/22m1519523

Analyzing Vector Orthogonalization Algorithms

2024· article· en· W4394761142 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.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueSIAM Journal on Matrix Analysis and Applications · 2024
Typearticle
Languageen
FieldComputer Science
TopicMatrix Theory and Algorithms
Canadian institutionsMcGill University
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsOrthogonalizationLanczos resamplingRoundingAlgorithmHermitian matrixOrthogonalityMathematicsConjugate gradient methodLanczos algorithmKrylov subspaceMatrix (chemical analysis)Round-off errorSequence (biology)Stiefel manifoldMachine epsilonIterative methodEigenvalues and eigenvectorsComputer science

Abstract

fetched live from OpenAlex

.Computer implementations of vector orthogonalization algorithms produce a sequence of supposedly orthogonal vectors, but rounding-errors can cause loss of orthogonality and rank. Nevertheless these computational algorithms can be very effective as parts of various methods. We develop a general theory based on the augmented orthogonal matrix developed in [SIAM J. Matrix Anal. Appl., 31 (2009), pp. 565–583] that can be applied to any such algorithm. This can be combined with a rounding-error analysis of the algorithm to analyze its finite-precision behavior. We apply this combination to prove that a particular Lanczos tridiagonalization of a Hermitian matrix always computes components for which backward-stable solutions to \(Ax\!=\!b\), \(A\!=\!A^H\), exist. If an appropriate rounding-error analysis is available, the approach can apparently be applied to any computation producing a sequence of supposedly orthogonal \(n\)-vectors, where a linear combination of these vectors is intended to approximate some quantity.Keywordsvector orthogonalizationfinite-precision computationsloss of orthogonalityLanczos processthe method of conjugate gradients (CG)Krylov subspace methodsconvergence of iterative solution of equationslarge sparse matricesMSC codes65F1065F2565F3065F5065G5015A2315A57

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.

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)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.942
Threshold uncertainty score0.947

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.003
Science and technology studies0.0000.000
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
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 head0.009
GPT teacher head0.285
Teacher spread0.276 · 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