Function newton_system_fixed_lazy 

pub fn newton_system_fixed_lazy<const N: usize, R, J>(
    residual_at: R,
    jacobian_at: J,
    start: [f64; N],
    criteria: Criteria,
) -> OgeomResult<([f64; N], f64, Convergence, usize)>
where
    R: FnMut(&[f64; N]) -> [f64; N],
    J: FnMut(&[f64; N]) -> Option<[[f64; N]; N]>,

newton_system_fixed with the residual and the Jacobian measured apart, the Jacobian only where a step is taken.

The damped search measures every trial point and keeps few, and where the Jacobian costs more than the residual (a spline surface’s derivatives against its point) most of that goes on Jacobians never used. The iteration is the one newton_system_fixed runs on |x| (residual(x), jacobian(x)), a None Jacobian standing for a point that cannot be measured: an infinite residual and a zero Jacobian. So it answers the same to the bit.

Errors

As newton_system_fixed.