Enumerative Sphere Shaping Library

This project implements the enumerative sphere shaping (ESS) (implementation follows this paper) and optimum ESS (OESS) algorithms in Rust. For ease of use it also contains the subproject pyrsess which provides Python bindings for the Rust code.

• Documentation
• Source
• PyRSESS

Installation

The Rust code can be compiled and run with cargo run. To use the Python bindings refer to the README in the pyrsess subfolder. An optimized build can be created using cargo build --release.

The documentation can be compiled with cargo doc. It can then be found as .html files in ./target/doc/ess/. The entry point is ./target/doc/rsess/index.html. By default the documentation focuses on the public interface of rsess. If the reader is interested in the inner workings of rsess, running cargo doc --document-private-items may yield additional insights.

Testing

Some test are located in src/tests.rs, these can be run with cargo test.

Rust Code Overview

• File src/lib.rs
  • Defines the trait DistributionMatcher
    • Fixes common methods for ESS and OESS
  • Defines the structs ESS and OESS which implement DistributionMatcher
    • User interfaces for the ESS / OESS algorithms
      • Offer the encode / decode functions
    • Offer utilities like calculating the amplitude distribution or average energy
  • Defines the struct ASK
    • Represents the amplitude shift keying modulation scheme
• File src/trellis.rs
  • Defines the struct Trellis
    • Represents the trellis used internally by the ESS and OESS algorithms
    • Implements (forward and reverse) trellis construction
    • Implements indexing algorithms used in encode / decode
• File src/iterators.rs
  • Defines an iterator Amplitudes
    • Iterates trough amplitude values in a given ASK with some extra constraints
  • Defines an iterator Energies
    • Iterates through energy levels in a trellis
• File src/tests.rs
  • Defines tests for the remaining code
  • Roughly divided into three sections: Trellis, ESS and OESS