Function select_objective_seed_on_log_lambda_grid 

pub fn select_objective_seed_on_log_lambda_grid<F>(
    rho_seed: &Array1<f64>,
    bounds: (f64, f64),
    n_smooths: usize,
    nullspace_coords: &[usize],
    eval_cost: F,
) -> Array1<f64>
where
    F: FnMut(&Array1<f64>) -> Option<f64>,

Choose an initial log-smoothing vector by evaluating the same objective the outer optimizer will minimize on a small deterministic grid around the analytic/heuristic seed.

This is initialization, not a fallback: no candidate is accepted unless it has a lower finite objective value under eval_cost, and the returned seed is still optimized by the normal outer solver.