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Record W4385076334 · doi:10.1016/j.ejor.2023.07.026

A linear programming approach to difference-of-convex piecewise linear approximation

2023· article· en· W4385076334 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

VenueEuropean Journal of Operational Research · 2023
Typearticle
Languageen
FieldMathematics
TopicAdvanced Optimization Algorithms Research
Canadian institutionsQueen's University
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsPiecewise linear functionPolytopeMathematical optimizationLinear programmingMathematicsBottleneckLinear approximationApproximation algorithmApproximation errorDimension (graph theory)AlgorithmComputer scienceDiscrete mathematicsNonlinear systemCombinatorics

Abstract

fetched live from OpenAlex

We address the problem of finding continuous piecewise linear (CPWL) approximations of deterministic functions of any dimension that satisfy any predefined error-tolerance, while keeping the number of polytopes that partition the approximation domain low. Specifically, we focus on overcoming the major computational bottleneck of the CPWL Approximation Algorithm (CPWL-AA) that has been proposed in the recent literature. CPWL-AA uses the difference-of-convex CPWL representation to search CPWL approximations which can partition the approximation domain to have polytopes of any shape. A computational bottleneck of the method is to solve a mixed-integer linear program (MILP) in which the number of binary variables is large for many problems of practical interest. In this paper, we overcome this by introducing a method that obtains a high quality solution of the MILP by iteratively solving a linear program (LP). We further reduce the computational expense by developing a method that treats some constraints in the LP problem as lazy constraints. Through a computational study we demonstrate that the proposed methods substantially reduce the computation time of CPWL-AA, while maintaining high quality CPWL approximations. With this, we demonstrate that we can generate CPWL approximations that satisfy predefined error-tolerances on functions of up to five dimensions within reasonable solution times.

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)0.009
metaresearch head score (Gemma)0.008
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
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 score0.484
Threshold uncertainty score0.981

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0090.008
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.002
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.001
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 head0.251
GPT teacher head0.446
Teacher spread0.195 · 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