The package license is now GPL-2, because the BOBYQA/NEWUOA ports and their R wrappers derive from the GPL-2 package 'minqa'.
M. J. D. Powell is added as an author for the BOBYQA/NEWUOA algorithms
and original Fortran code; sources and notices for all ported code
('trust', 'basin', 'minqa', Powell's Fortran) are listed in inst/COPYRIGHTS.
New steihaug(): a Steihaug truncated conjugate-gradient trust-region
Newton minimizer ported from the Rust crate 'basin', with exact-Hessian
and matrix-free (Hessian-vector product) modes, and a thread-safe C
entry point steihaug_solve_c().
New bobyqa() and newuoa(): thread-safe C++ ports of Powell's
derivative-free BOBYQA and NEWUOA from 'minqa' 1.2.8, drop-in
replacements for minqa::bobyqa()/minqa::newuoa(), with C entry points
bobyqa_solve_c()/newuoa_solve_c(). BOBYQA's RESCUE step evaluates
the intended point rather than minqa's uninitialized one.
.RcppTrustPtr() and RcppTrust.h gain appended slots for the new C
entry points and their result-free functions.
New vignette vignette("trust-region-methods").