v0.4.1

• Improvements
  • Improved compression speed 10-20% by simplifying histogram partitioning, learning from Rust 1.81's new sorting algorithms.
  • Made compression avoid offset bits when it causes little harm to compression ratio, improving compression and decompression speed in specific cases.
• CLI
  • Added delta=Lookback chunk config support.
  • Added Parquet 16-bit data type support in benchmarks.

Python v0.3.2

Upgraded Rust implementation to 0.4.1.

v0.4.0

• New format version (3)
• API breaking changes
  • All metadata types (e.g. ChunkMeta) now live in the pco::metadata:: module.
  • Metadata and ChunkCompressor types are no longer generic to latent type. Instead they contain dynamically-typed values, leveraging the dtype_dispatch crate.
  • Renamed NumberLike => Number.
  • Delta encoding is now configured via DeltaSpec enum of an Option<usize>, and similarly ChunkMeta contains a DeltaEncoding enum.
• API additions
  • Added simple_compress_into function.
  • Added a Lookback delta encoding that improves compression ratio on some types of data.
• Improvements
  • Improved bin optimization speed on Windows slightly.
  • Improved FloatQuant auto mode heuristics, improving the size/speed tradeoff.
  • Reduced binary size via fewer unnecessary specializations.
• Degradations
  • Automatic detection of the new Lookback delta encoding is fairly slow, often increasing compression time ~10%. We're likely to try ameliorating this in future releases.

Python v0.3.1

• Added DeltaSpec.try_lookback() configuration.
• Upgraded Rust implementation to 0.4.0.

Python v0.3.0

• Published Python 3.13 wheels for the first time (assuming this works).
• Replaced delta_encoding_order optional int configuration with delta_spec class.

v0.3.1

Reduced minimum version requirement for half crate.

v0.3.0

• New format version (2)
• API breaking changes
  • Replaced FloatMultSpec and IntMultSpec with mode_spec: ModeSpec in ChunkConfig.
  • Removed auto_delta_encoding_order function.
• API additions
  • Added support for 16-bit data types.
  • Added LatentDescriber API, accessible by NumberLike::get_latent_describer.
• Improvements
  • Added FloatQuant mode and automatic detection for it, improving compression ratio on quantized float data.
  • Increased compression speed for high compression levels slightly.

Python v0.2.0

• Added support for 16-bit types.
• Replaced separate int_mult_spec and float_mult_spec configs withmode_spec: ModeSpec.
• Upgraded Rust implementation from 0.2.5 to 0.3.0.

Python v0.1.1

Upgraded Rust implementation from 0.1.3 to 0.2.5.

v0.2.5

Fixed a bug in v0.2.4 that caused a panic during histogram computation under certain conditions.