Optimize i = !is.na(...)
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Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 35/100
- Issue type
- Refactor
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- r
- Domain
- data, performance
Research direction
Start by tracing data.table's implementation of i = !is.na(...) and :=, using the linked Stack Overflow example as the behavioral reference. Identify tests covering this expression and measure its current working-memory use; done means the fused operation preserves the result without allocating two columns of working RAM.
Written by the indexing model from the issue text.
Description
Loop fuse so that it doesn't churn through 2 column's worth of working RAM. In fact, no working RAM is needed at all if it does the := as well as it loops through i. So fuse the i into the := step too.
http://stackoverflow.com/a/33024625/403310
- Dominant language
- R
- Stars
- 3.9k
- Forks
- 1.1k
- Avg merge
- 14h 4m
- Merged PRs (30d)
- 4
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.
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