A subsampled truncated-Newton method for multiparameter full-waveform inversion
Bibliographic record
Abstract
ABSTRACT Accounting for the Hessian in full-waveform inversion (FWI) can lead to higher convergence rates, improved resolution, and better mitigation of parameter trade-off in multiparameter problems. In spite of these advantages, the adoption of second-order optimization methods (e.g., truncated Newton [TN]) has been precluded by their high computational cost. We propose a subsampled TN (STN) algorithm for time-domain FWI with applications presented for the elastic isotropic case. By using uniform or nonuniform source subsampling during the computation of Hessian-vector products, we reduce the number of partial differential equation solves required per iteration when compared to the conventional TN algorithm. We evaluate the performance of STN through synthetic inversions on the Marmousi II and BP 2.5D models, using the limited-memory Broyden–Fletcher–Goldfarb–Shanno and TN algorithms as benchmarks. We determine that STN reaches a target misfit reduction at an overall cost comparable to first-order gradient methods, while retaining favorable convergence properties of TN methods. Furthermore, we evaluate an example in which nonuniform sampling outperforms uniform sampling in STN due to highly nonuniform source contributions to the Hessian.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".