Fix bug in implicit type conversion to unsigned type in `clamp` function. This would fail with underflow error when we attempted to subtract radius from 0.
Fix bug in implicit type conversion to unsigned type in `clamp` function. This would fail with underflow error when we attempted to subtract radius from 0.

innolitics/natural-neighbor-interpolation,innolitics/natural-neighbor-interpolation,innolitics/natural-neighbor-interpolation