Function approximate 

pub fn approximate(
    points: &[Point3],
    degree: usize,
    num_control_points: usize,
) -> Result<NurbsCurve, MathError>

Approximate a set of points with a NURBS curve of specified number of control points.

Uses least-squares fitting: the resulting curve minimizes the sum of squared distances to the data points. The curve generally does NOT pass through the points unless num_control_points == points.len().

Errors

Returns an error if parameters are invalid.