Expand description
ConvCheck trait — port of IpConvCheck.hpp.
Upstream ConvergenceCheck::CheckConvergence reads the NLP error
and iter count off IpData()/IpCq(). The default trait method
pushes that read to the caller (the main loop in ipopt_alg.rs)
so simple convergence policies stay pure scalar state machines
over (nlp_err, iter_count). The richer
ConvCheck::check_convergence_with_state entry point exposes
the live (IpoptData, IpoptCq) so policies that need iterate
components — notably the restoration-side
RestoFilterConvergenceCheck::TestOrigProgress — can read them.
Default impl just delegates to the scalar method, preserving
backwards compatibility for every existing impl.