Stability and numerical dispersion analysis of CE-FDTD method
Bibliographic record
Abstract
The complex-envelope finite-difference time-domain (CE-FDTD) method has been developed in order to efficiently simulate electromagnetic structures with band-limited signals. This method has most often been formulated in terms of wave equations, leaving its numerical properties significantly understudied. In this paper, full-wave CE-FDTD formulations, and a comprehensive analysis of the numerical stability and dispersion of this method are presented. It is found that that the maximum time step allowed for stability is strongly dependent upon the ratio of the carrier wavelength to spatial step sizes. When this ratio is larger than a threshold value, the time step is bounded by a Courant-Frederick-Levy (CFL) condition. When this ratio is lower than the threshold value, the time step is no longer bounded by this stability condition. However, in such instances, the associated numerical dispersion errors become unacceptably large (more than 200%). Therefore, in comparison with the conventional FDTD method, the CE-FDTD method is proven to be not advantageous in terms of computation efficiency for an accuracy of a similar level.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
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 teacher head, 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".