Commit Graph

2 Commits

Author SHA1 Message Date
Eric Coissac
a016ad5b8a Refactor kmer index to disk-based partitioning with minimizer
Refactor kmer index package to use disk-based partitioning with minimizer

- Replace roaring64 bitmaps with disk-based kmer index
- Implement partitioned kmer sets with delta-varint encoding
- Add support for frequency filtering during construction
- Introduce new builder pattern for index construction
- Add streaming operations for set operations (union, intersect, etc.)
- Add support for super-kmer encoding during construction
- Update command line tool to use new index format
- Remove dependency on roaring bitmap library

This change introduces a new architecture for kmer indexing that is more memory efficient and scalable for large datasets.
2026-02-09 17:52:37 +01:00
Eric Coissac
500144051a Add jj Makefile targets and k-mer encoding utilities
Add new Makefile targets for jj operations (jjnew, jjpush, jjfetch) to streamline commit workflow.

Introduce k-mer encoding utilities in pkg/obikmer:
- EncodeKmers: converts DNA sequences to encoded k-mers
- ReverseComplement: computes reverse complement of k-mers
- NormalizeKmer: returns canonical form of k-mers
- EncodeNormalizedKmers: encodes sequences with normalized k-mers

Add comprehensive tests for k-mer encoding functions including edge cases, buffer reuse, and performance benchmarks.

Document k-mer index design for large genomes, covering:
- Use cases and objectives
- Volume estimations
- Distance metrics (Jaccard, Sørensen-Dice, Bray-Curtis)
- Indexing options (Bloom filters, sorted sets, MPHF)
- Optimization techniques (k-2-mer indexing)
- MinHash for distance acceleration
- Recommended architecture for presence/absence and counting queries
2026-02-04 14:27:10 +01:00