CosmoStat / CosmoStat/sp_validation
m-bias errors: leave-one-tile-out jackknife; drop the cumulative file
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- Dominant language
- Python
- Stars
- 2
- Forks
- 5
- Avg merge
- 1d 14h
- Merged PRs (30d)
- 19
Description
ImageSimMBias computes m/c on the full pooled sample with a paired object bootstrap. Object resampling assumes galaxies are independent, but tile-level systematics (PSF model, background, selection) correlate objects within a tile, so the bootstrap can underestimate the error.
- Carry a tile id per object through the extracted cut catalogue (patch name from
final_cat_*.hdf5). - Add a leave-one-tile-out jackknife for m/c errors, reported alongside the bootstrap; disagreement between the two is itself a tile-systematics diagnostic.
- Replace
mbias_cumulative.yaml/plot_convergence(stateful across runs, mixes code versions) with an in-run convergence curve: m on the first k tiles, k=1..N, jackknife errors.
Raised by Fabian (Slack, 2026-09-14); he'd read the cumulative plot as per-tile averaging — the estimator is already full-sample.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by tracing ImageSimMBias and the extracted cut catalogue, including how patch names from final_cat_*.hdf5 are handled. Then inspect mbias_cumulative.yaml and plot_convergence. Done means tile IDs are carried through, leave-one-tile-out jackknife errors appear alongside bootstrap errors, and convergence is computed in-run without the cumulative file.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data, testing-qa
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100