Fix Apple Clang weak symbols warnings Change-Id: I71eba56ca37060c83d05ff14d6f9bfaef61e9493
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.