commit 83098e12e8b2252797a6570ba340c181eeddbd07
author Sameer Agarwal <sameeragarwal@google.com> Fri Mar 02 17:19:42 2018 -0800
committer Sameer Agarwal <sameeragarwal@google.com> Tue Mar 06 19:12:14 2018 +0000
tree 4952ba9060a66505b1d2c7ce98a225d8d7c864f8
parent df2d882540872a399bb1841798b57d6afdc96e7a

Two changes to how we manage user's state.

1. When Solver::Options::update_state_every_iteration = true,
   the StateUpdatingCallback only updates the state on a
   successful iteration. This works fine but will not work
   if the user provides an EvaluationCallback, because
   every call to Evaluator::Evaluate will change the state
   visible to the user. This means that on unsuccessful
   iterations when the user's IterationCallback is called
   the state visible to the user would be the last evaluation
   which did not lead to an improved cost. This CL forces
   the StateUpdatingCallback to unconditionally update
   the user visible state.

2. When the minimizer terminates, we update the user visible
   state only if the solution is usable, otherwise the user's
   state will remain the same. To maintain this invariant
   we will now cache the user's state and make sure we
   use it to reset it upon return if the solver is not
   successful.

Change-Id: Ic1f8fa6cb10d2753130ea752c70ff3d6b2f1462f