Release 0.4.0

What's Changed

Added

• OpenQASM 3.0 Export - Export quantum circuits to OpenQASM format for real quantum hardware execution
  • Full support for OpenQASM 3.0 syntax including conditionals
  • Export via Qx.Export.OpenQASM.to_qasm/2 with customizable options
  • Supports all quantum gates, measurements, barriers, and conditional operations
  • Enables seamless integration with IBM Quantum, Rigetti, and other quantum hardware platforms
• Error Handling Documentation (qx-gd5) - Comprehensive CONTRIBUTING.md with error handling philosophy and best practices
  • Detailed guidelines for error types, messages, and recovery strategies
  • Error handling patterns for library developers
  • Examples of proper error propagation and context enrichment
  • Documentation of all custom error types and their use cases
• Test Coverage Integration (qx-xbf) - Complete test coverage metrics and CI/CD integration
  • Added ExCoveralls dependency for code coverage reporting
  • Achieved 66.4% test coverage across the codebase
  • Integrated coverage reporting into CI/CD pipeline
  • Configured multiple coverage output formats (HTML, JSON, Cobertura)
  • Added GitHub Actions integration for coverage tracking

Changed

• Predicate Function Conventions (qx-7iw) - Enhanced predicate naming and specifications
  • Added @spec type specifications to all predicate functions
  • Improved naming conventions for boolean-returning functions
  • Enhanced documentation for predicate function usage patterns
  • Better consistency across module APIs
• Module Documentation (qx-sdb) - Verified comprehensive module documentation
  • Confirmed all modules have proper @moduledoc documentation
  • Ensured consistent documentation style across the codebase
  • Enhanced module-level descriptions and usage examples

Fixed

• Credo strict mode compliance in OpenQASM export module
  • Refactored complex pattern matching to reduce cyclomatic complexity
  • Used Enum.map_join/3 for better performance
  • Added inline Credo exception for legitimate gate mapping complexity

Improved

• Development workflow with better error handling guidelines
• Code quality with comprehensive type specifications
• Test coverage visibility and tracking
• Documentation completeness and consistency
• Hardware integration capabilities via OpenQASM export

Installation

Add to your mix.exs:

def deps do
  [
    {:qx_sim, "~> 0.4.0"}
  ]
end

Documentation

• Hex.pm: https://hex.pm/packages/qx_sim/0.4.0
• Docs: https://hexdocs.pm/qx_sim/0.4.0

Release 0.3.0

What's Changed

Added

• Runtime Backend Selection - Major new feature allowing backend specification at runtime without compile-time configuration
  • Added :backend option to Qx.run/2, Qx.get_state/2, and Qx.get_probabilities/2
  • Users can now specify different backends for different circuits: Qx.run(circuit, backend: EXLA.Backend)
  • Supports all Nx backends including EXLA (CPU/CUDA/ROCm) and EMLX (Apple Silicon GPU)
  • Combines with other options: Qx.run(circuit, backend: EXLA.Backend, shots: 2048)
  • Maintains full backward compatibility with existing code
  • Implemented using Nx.with_default_backend/2 for proper scoped execution
  • Comprehensive documentation added to README.md with usage examples and best practices

Changed

• Draw Module Refactoring - Reorganized visualization code for better maintainability and clarity
  • Split large 1,531-line Qx.Draw module into 5 focused sub-modules:
    • Qx.Draw.VegaLite - VegaLite chart generation for LiveBook (178 lines)
    • Qx.Draw.SVG.Charts - SVG histogram and bar charts (199 lines)
    • Qx.Draw.SVG.Bloch - Bloch sphere visualization with 3D projection (267 lines)
    • Qx.Draw.SVG.Circuit - Quantum circuit diagrams with IEEE notation (596 lines)
    • Qx.Draw.Tables - State table formatting with Kino support (196 lines)
  • Qx.Draw now serves as a clean API facade, delegating to specialized sub-modules
  • Maintains 100% backward compatibility - no API changes required
  • Improved code organization following single responsibility principle
  • Better separation of concerns between rendering formats and visualization types
  • All 557 tests continue to pass

Fixed

• Fixed Nx backend configuration anti-pattern where library imposed compile-time backend choices on users
• Eliminated warnings about undefined Nx.default_backend/2 function

Installation

Add to your mix.exs:

def deps do
  [
    {:qx_sim, "~> 0.3.0"}
  ]
end

Documentation

• Hex.pm: https://hex.pm/packages/qx_sim/0.3.0
• Docs: https://hexdocs.pm/qx_sim/0.3.0

Release 0.2.5

What's Changed

Fixed

• More fixes to the pipeline

Installation

Add to your mix.exs:

def deps do
  [
    {:qx_sim, "~> 0.2.5"}
  ]
end

Documentation

• Hex.pm: https://hex.pm/packages/qx_sim/0.2.5
• Docs: https://hexdocs.pm/qx_sim/0.2.5

v0.2.3: Fix Nx.Defn Compilation Errors

Fixed

• Simplified application configuration to resolve Nx.Defn compilation issues
• Removed unnecessary application dependencies that were causing compile-time conflicts

Installation

def deps do
  [
    {:qx_sim, "~> 0.2.3"}
  ]
end

Links

• Hex.pm Package: https://hex.pm/packages/qx_sim/0.2.3
• Documentation: https://hexdocs.pm/qx_sim/0.2.3
• Changelog: https://github.com/richarc/qx/blob/main/CHANGELOG.md

What's Changed

This is a bug fix release addressing compilation errors that some users experienced when installing qx_sim from Hex.pm. The error "module Nx.Defn is not loaded" has been resolved by simplifying the application configuration.

Full Changelog: v0.2.2...v0.2.3

Qx v0.2.1 - Quantum Computing Simulator

Full Changelog: v0.2.0...v0.2.1

Qx v0.2.0 - Quantum Computing Simulator

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog,
and this project adheres to Semantic Versioning.

0.2.0 - 2025-11-01

Added

Core Quantum Computing Features

• Full quantum circuit API with chainable operations via Qx module
• Support for 20+ quantum gates including:
  • Single-qubit gates: H, X, Y, Z, S, T, Sdg, Tdg
  • Parametric rotation gates: RX, RY, RZ with arbitrary angles
  • Two-qubit gates: CNOT (CX), CZ (Controlled-Z), SWAP
  • Multi-qubit support up to 20 qubits
• Measurement operations with classical bit storage and reset capabilities
• Conditional operations based on classical measurement results
• Statevector simulation using Nx tensors with Complex64 format
• Direct state access via Qx.get_state/1

Visualization

• Circuit visualization using VegaLite
• Multiple chart styles: bar charts, probability distributions, Bloch sphere
• SVG export capability for publication-quality figures
• Example visualization scripts in examples/ directory

Performance & Acceleration

• EXLA backend integration for CPU acceleration
• EMLX backend support for Apple Silicon GPU acceleration (M1/M2/M3/M4)
• Automatic backend detection and configuration
• JIT compilation support via Nx.Defn

Benchmarking Suite

• Professional benchmarking infrastructure using Benchee
• GHZ state scaling benchmarks (5, 10, 15, 20 qubits)
• Backend comparison benchmarks (Binary, EXLA CPU, EMLX GPU, EXLA CUDA/ROCm)
• HTML report generation with interactive graphs
• Statistical analysis with warmup, iterations, and memory profiling
• Safe GPU backend detection with graceful fallback

Documentation & Examples

• Comprehensive API documentation with examples
• Example files demonstrating:
  • Basic quantum circuit operations
  • Complex number handling
  • Bell state creation
  • Quantum teleportation protocol
  • Conditional circuit operations
  • Grover's search algorithm
  • Circuit visualization techniques
• Performance benchmarking guide
• Backend configuration documentation

Error Handling

• Structured error types for better debugging:
  • Qx.QubitIndexError - Invalid qubit indices
  • Qx.StateNormalizationError - State vector normalization issues
  • Qx.MeasurementError - Measurement failures
  • Qx.ConditionalError - Conditional operation errors
  • Qx.ClassicalBitError - Classical bit access errors
  • Qx.GateError - Gate application failures
  • Qx.QubitCountError - Invalid qubit count specifications

Changed

• Updated state representation to use :c64 (Complex64) tensor format for improved performance
• Migrated from Torchx to EMLX for Apple Silicon GPU acceleration (pure Elixir, no Python)
• Enhanced error messages with context and suggestions
• Improved documentation structure with module grouping
• Updated examples to work with latest Complex number API

Fixed

• Complex number handling in example files for :c64 format
• CZ gate now properly exposed in main Qx module API
• Backend detection error handling for unavailable GPU platforms
• Output directory creation in visualization examples
• Grover's algorithm now uses proper CZ gates instead of H-CX-H decomposition

Developer Experience

• Added :usage_rules dependency for better development ergonomics
• Comprehensive test suite with 549 passing tests
• Modular architecture separating concerns (Circuit, Operations, Simulation, etc.)
• Clean API design following Elixir conventions

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0.1.0 - 2024-10-05

Added

• Initial release
• Basic quantum circuit functionality
• Core gate operations
• Statevector simulation
• Nx backend integration

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Future Roadmap

Potential Additions

• Additional quantum gates (Toffoli, Fredkin, controlled rotations)
• Quantum Fourier Transform implementation
• Noise models for realistic simulations
• Density matrix simulation for mixed states
• OpenQASM import/export
• Performance optimizations for larger circuits
• Integration with quantum hardware providers

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