Fengzdadi opened a new issue, #98: URL: https://github.com/apache/datasketches-go/issues/98
## Overview This issue tracks the implementation of `VarOptItemsSketch` (Variance Optimal Sampling) for the Go library, following the Java and C++ implementations. VarOpt provides weighted sampling with optimal variance for subset sum estimation - useful for network traffic monitoring, ad analytics, and log sampling. ## Proposed Implementation Plan We plan to split this into **multiple PRs** for easier review: ### PR 1: Core VarOptItemsSketch (basic functionality) - [ ] Add `VarOptItems` family (ID=13) to `internal/family.go` - [ ] Implement `VarOptItemsSketch[T]` struct with fields: k, n, h, m, r, totalWtR, data, weights - [ ] Implement warmup mode (n ≤ k): store all items - [ ] Implement estimation mode (n > k): weighted sampling with tau threshold - [ ] Min-heap operations for H region - [ ] Basic unit tests ### PR 2: Serialization & Compatibility - [ ] Implement `ToByteArray()` (Java-compatible format) - [ ] Implement `NewVarOptItemsSketchFromSlice()` - [ ] Add cross-language compatibility tests - [ ] Generate test data files for validation ### PR 3: Subset Sum Estimation - [ ] Implement `EstimateSubsetSum(predicate)` returning bounds - [ ] Pseudo-hypergeometric confidence intervals - [ ] Tests for estimation accuracy ### PR 4: VarOptItemsUnion (optional, can be deferred) - [ ] Implement union with gadget/marks mechanism - [ ] Serialization for union state ## References - Java: [`VarOptItemsSketch.java`](https://github.com/apache/datasketches-java/blob/master/src/main/java/org/apache/datasketches/sampling/VarOptItemsSketch.java) - C++: [`var_opt_sketch.hpp`](https://github.com/apache/datasketches-cpp/blob/master/sampling/include/var_opt_sketch.hpp) - Algorithm paper: [Variance Optimal Sampling](https://datasketches.apache.org/docs/Sampling/VarOptSamplingSketches.html) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
