Function nbFindSpan

cadquery/occ_impl/nurbs.py:407–453

NURBS book A2.1 with modifications to handle periodic usecases. Parameters ---------- u : float Parameter value. order : int Spline order. knots : ndarray Knot vector. Returns ------- Span index.

(
    u: float,
    order: int,
    knots: Array,
    low: Optional[int] = None,
    high: Optional[int] = None,
)

@njiti
def nbFindSpan(
    u: float,
    order: int,
    knots: Array,
    low: Optional[int] = None,
    high: Optional[int] = None,
) -> int:
    """
    NURBS book A2.1 with modifications to handle periodic usecases.

    Parameters
    ----------
    u : float
        Parameter value.
    order : int
        Spline order.
    knots : ndarray
        Knot vector.

    Returns
    -------
    Span index.

    """

    if low is None:
        low = order

    if high is None:
        high = knots.shape[0] - order - 1

    mid = (low + high) // 2

    if u >= knots[-1]:
        return high - 1  # handle last span
    elif u < knots[0]:
        return low

    while u < knots[mid] or u >= knots[mid + 1]:
        if u < knots[mid]:
            high = mid
        else:
            low = mid

        mid = (low + high) // 2

    return mid


@njiti