scatter estimate contains tiny negatives
Nobody has claimed this yet.
- Dominant language
- C++
- Stars
- 160
- Forks
- 113
- Avg merge
- 12d 15h
- Merged PRs (30d)
- 1
Description
Due to numerical rounding errors, and tricks played with thresholding to cope with zero efficiencies, the scatter estimate can contain negatives of the order of 1E-28. this might confuse some algorithms/people so maybe we should threshold them.
culprit code is likely
https://github.com/UCL/STIR/blob/b5ed62bfa581177e9f9d8fc355cf1317ee9e509f/src/scatter_buildblock/ScatterEstimation.cxx#L610-L615
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
Open src/scatter_buildblock/ScatterEstimation.cxx around lines 610-615 and inspect the thresholding used for zero efficiencies. Reproduce an estimate containing values around -1E-28, then determine the appropriate numerical threshold and verify that scatter estimates no longer expose tiny negative values.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- computer-vision
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100