Use absl::btree_map instead of std::map Change-Id: Iece280a6cb0f37fa0bc572046b9d7f79ca825ebc
Ceres Solver is an open source C++ library for modeling and solving large, complicated optimization problems. It is a feature rich, mature and performant library which has been used in production at Google since 2010. Ceres Solver can solve two kinds of problems.
Please see ceres-solver.org for more information.