Installation¶

Install from PyPI¶

pip install solweig

Verify the installation:

python -c "import solweig; print(solweig.__version__)"

Install from Source (for development)¶

To modify the code or contribute:

Python 3.11+
Rust toolchain — required to compile the compute core (install Rust)
uv — Python package manager (install uv)

git clone https://github.com/UMEP-dev/solweig.git
cd solweig
uv sync              # Install Python dependencies
maturin develop      # Compile Rust extension and link it

Optional Dependencies¶

SOLWEIG operates with numpy arrays alone, but file-based workflows benefit from the following packages:

Package	Purpose
`rasterio`	Loading/saving GeoTIFF rasters (installed by default)
`geopandas`	Rasterising vector data (e.g. tree polygons to a canopy grid)
`affine`	Geospatial coordinate transforms (installed by default)
`pyproj`	CRS handling and coordinate conversion (installed by default)

If only numpy arrays are used, rasterio and geopandas are not required.

GPU Acceleration¶

SOLWEIG uses GPU acceleration (via wgpu/Metal/Vulkan) when available. No additional setup is required.

import solweig

print(f"GPU available: {solweig.is_gpu_available()}")
print(f"Backend: {solweig.get_compute_backend()}")  # "gpu" or "cpu"

If no GPU is found, computation falls back to CPU. To force CPU mode:

solweig.disable_gpu()

Troubleshooting¶

`maturin: command not found`¶

Install via uv or pip:

uv tool install maturin
# or
pip install maturin

Build errors on macOS¶

Ensure Xcode command line tools are installed:

xcode-select --install

`import solweig` fails after `maturin develop`¶

Ensure the same Python environment created by uv sync is active. If using uv:

uv run python -c "import solweig; print('OK')"