Crate seqpacker 

seqpacker

High-performance sequence packing for LLM training.

Seqpacker solves the bin-packing problem for variable-length sequences: given a set of sequences and a maximum pack length, pack them into the fewest bins possible while minimizing padding waste.

Quick Start

use seqpacker::{Packer, PackStrategy, Sequence};

let packer = Packer::new(2048)
    .with_strategy(PackStrategy::FirstFitDecreasing);

let sequences = vec![
    Sequence::new(0, 500),
    Sequence::new(1, 600),
    Sequence::new(2, 400),
];

let result = packer.pack(sequences).unwrap();
println!("Efficiency: {:.2}%", result.metrics.efficiency * 100.0);

Available Algorithms

Algorithm	Time	Approx. Ratio	Best For
NextFit	O(n)	2.0	Memory-constrained streaming
FirstFit	O(n log B)	1.7	Online baseline
BestFit	O(n log B)	1.7	Tighter packing
WorstFit	O(n log B)	2.0	Even distribution
FirstFitDecreasing	O(n log n)	1.22	Default offline (recommended)
BestFitDecreasing	O(n log n)	1.22	Tightest offline packing
FirstFitShuffle	O(n log n)	~1.3	Training randomness
ModifiedFirstFitDecreasing	O(n log n)	1.18	Mixed-size distributions
Harmonic-K	O(n)	~1.69	Bounded-space online

Re-exports

pub use error::PackError;

pub use metrics::PackMetrics;

pub use pack::Pack;

pub use packer::PackResult;

pub use packer::Packer;

pub use packer::PackerConfig;

pub use sequence::Sequence;

pub use strategy::PackStrategy;

pub use stream::StreamPacker;

pub use stream::StreamStrategy;

Modules

algorithms

Bin-packing algorithm implementations.

dev

Development helpers and debugging macros.

engine

Generic greedy packing engine.

error

Error types for the seqpacker library.

metrics

Packing quality metrics.

pack

Bin and Pack types for packing output.

packer

Main Packer interface - entry point for users.

placement

PlacementIndex trait and implementations for bin selection.

sequence

Input sequence types for packing.

strategy

Packing strategy enum and algorithm trait.

stream

Streaming packer for bounded-space online algorithms.

validation

Solution validation — checks all universal packing invariants.

Macros

dbg_type

Print a value’s type and content for debugging.