Function nbCurveDer

cadquery/occ_impl/nurbs.py:667–729

NURBS book A3.2 with modifications to handle periodicity. Parameters ---------- u : Array Parameter values. order : int B-spline order. dorder : int Derivative order. knots : Array Knot vector. pts : Array Control points.

(
    u: Array, order: int, dorder: int, knots: Array, pts: Array, periodic: bool = False
)

@njit
def nbCurveDer(
    u: Array, order: int, dorder: int, knots: Array, pts: Array, periodic: bool = False
) -> Array:
    """
    NURBS book A3.2 with modifications to handle periodicity.

    Parameters
    ----------
    u : Array
        Parameter values.
    order : int
        B-spline order.
    dorder : int
        Derivative order.
    knots : Array
        Knot vector.
    pts : Array
        Control points.
    periodic : bool, optional
        Periodicity flag. The default is False.


    Returns
    -------
    Array
        Curve values and derivatives.

    """
    # number of control points
    nb = pts.shape[0]

    # handle periodicity
    u_, knots_ext, minspan, maxspan, deltaspan = _preprocess(u, order, knots, periodic)

    # number of param values
    nu = np.size(u)

    # chunk size
    n = order + 1

    # temp chunk storage
    temp = np.zeros((dorder + 1, n))

    # initialize
    out = np.zeros((nu, dorder + 1, 3))

    for i in range(nu):
        ui = u_[i]

        # find span
        span = nbFindSpan(ui, order, knots, minspan, maxspan) + deltaspan

        # evaluate chunk
        nbBasisDer(span, ui, order, dorder, knots_ext, temp)

        # multiply by ctrl points
        for j in range(order + 1):
            for k in range(dorder + 1):