bad bug in decompose, radical
Nobody has claimed this yet.
- Dominant language
- Macaulay2
- Stars
- 435
- Forks
- 297
- Avg merge
- 4d 20h
- Merged PRs (30d)
- 11
Description
We need to find and fix this bug before the next release!
```
restart
n = 5
R = ZZ/32003[x_0..x_(n-1),y_0..y_(n-1)];
Itrig = ideal apply(n, i->x_i^2+y_i^2-1);
SegreI =minors(2,genericMatrix(R,n,2))
I=Itrig+SegreI; -- this is a radical ideal with 16 components, all the same dimension.
tally for i from 0 to 20 list (J := ideal I_*; radical J == J)
```
This last line sometimes gives the right answer (all true's), sometimes some true and some false, and sometimes it gives an error.
I'm not sure when this bug started (the bug occurs on M2 1.20 as well, I think).
Contributor guide
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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
Run the supplied Macaulay2 script and focus on the final tally over the ideals I_*. Investigate the decompose/radical computation exercised by `radical J == J`; done means repeated runs consistently return the correct radical results for all 16 components without errors.
Written by the indexing model from the issue text.
Assessment
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 30/100