Cython library that constructs a piecewise polynomial surrogate model on scattered point-cloud data in 1D, 2D, or 3D, by weighted least squares. From the surrogate you read off the function value and ...

3. The pure Python fallback (fastmath/_fallback.py) must implement the same functions using only numpy. 4. The __init__.py must try to import from .core, falling back to ._fallback.