pylibsparseir 0.6.0

Python bindings for the libsparseir library

Python bindings for libsparseir

This is a low-level binding for the libsparseir library.

Requirements

• Python >= 3.10
• CMake (for building the C++ library)
• C++11 compatible compiler
• numpy >= 1.26.4
• scipy

BLAS Support

This package automatically uses SciPy's BLAS backend for optimal performance. No additional BLAS installation is required - SciPy will provide the necessary BLAS functionality.

Build

Install Dependencies and Build

# First, prepare the build by copying necessary files from parent directory
python3 prepare_build.py

# Then build the package
uv build

This will:

• Copy source files (src/, include/, cmake/) from the parent libsparseir directory
• Build the C++ libsparseir library using CMake with automatic BLAS support via SciPy
• Create both source distribution (sdist) and wheel packages

Development Build

For development:

# Install in development mode (will auto-prepare if needed)
uv sync

Note for CI/CD: In CI environments, you must run prepare_build.py before building:

# In CI/CD scripts
cd python
python3 prepare_build.py
uv build

See .github-workflows-example.yml for a complete GitHub Actions example.

BLAS Configuration

The package automatically uses SciPy's BLAS backend, which provides optimized BLAS operations without requiring separate BLAS installation. The build system is configured to use SciPy's BLAS functions directly.

Clean Build Artifacts

To remove build artifacts and files copied from the parent directory:

uv run clean

This will remove:

• Build directories: build/, dist/, *.egg-info
• Copied source files: include/, src/, cmake/ (copied by prepare_build.py)
• Compiled libraries: pylibsparseir/*.so, pylibsparseir/*.dylib, pylibsparseir/*.dll
• Cache directories: pylibsparseir/__pycache__

Build Process Overview

The build process works as follows:

1. File Preparation: prepare_build.py copies necessary files from the parent libsparseir directory:

   • Source files (../src/ → src/)
   • Header files (../include/ → include/)
   • CMake configuration (../cmake/ → cmake/)

2. Package Building: uv build or uv sync uses scikit-build-core to:

   • Configure CMake with automatic BLAS support via SciPy
   • Compile the C++ library with dynamic BLAS symbol lookup (for SciPy compatibility)
   • Package everything into distributable wheels and source distributions

3. Installation: The built package includes the compiled shared library and Python bindings

Why File Copying?: The prepare_build.py script copies files from the parent directory instead of using symbolic links to ensure:

• Cross-platform compatibility (Windows doesn't handle symlinks well)
• Proper inclusion in source distributions (sdist)
• Clean separation between the main C++ library and Python bindings

Conda Build

This package can also be built and distributed via conda-forge. The conda recipe is located in conda-recipe/ and supports multiple platforms and Python versions.

Building conda packages locally:

# Install conda-build
conda install conda-build

# Build the conda package
cd python
conda build conda-recipe

# Build for specific platforms
conda build conda-recipe --platform linux-64
conda build conda-recipe --platform osx-64
conda build conda-recipe --platform osx-arm64

Supported platforms:

• Linux x86_64
• macOS Intel (x86_64)
• macOS Apple Silicon (ARM64)

Supported Python versions:

• Python 3.11, 3.12, 3.13

Supported NumPy versions:

• NumPy 2.1, 2.2, 2.3

The conda build automatically:

• Uses SciPy's BLAS backend for optimal performance
• Cleans up old shared libraries before building
• Builds platform-specific packages with proper dependencies

Performance Notes

BLAS Support

This package automatically uses SciPy's optimized BLAS backend for improved linear algebra performance:

• Automatic BLAS: Uses SciPy's BLAS functions for optimal performance
• No additional setup: SciPy provides all necessary BLAS functionality

The build system automatically configures BLAS support through SciPy. You can verify BLAS support by checking the build output for messages like:

export SPARSEIR_DEBUG=1
python -c "import pylibsparseir"

This will show:

BLAS support enabled
Registered SciPy BLAS dgemm @ 0x...

Troubleshooting

Build fails with missing source files:

# Make sure to run prepare_build.py first
python3 prepare_build.py
uv build

Clean rebuild:

# Remove all copied files and build artifacts
uv run clean
python3 prepare_build.py
uv build