Function approximate 

pub fn approximate(
    points: &[Point],
    degree: usize,
    control_count: usize,
    spacing: Spacing,
    tol: Tolerances,
) -> OgeomResult<BSplineCurve>

Fit a B-spline that passes near the points, with control_count control points.

The first and last points are interpolated exactly: a fitted curve that does not start where the data starts is almost never wanted, and the ends are where a free least-squares fit goes worst.

Errors

OgeomError::Construction if there are too few points, if control_count does not leave the system overdetermined, or if the normal equations are singular.