tree 6ef6f4a4627e928f5dacdb9517da154f5c4238e4
parent bd90384226a7f8629467f72fc410a9e8086a2dff
author Sameer Agarwal <sameeragarwal@google.com> 1402029013 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1408393891 -0700

Refactor SolverImpl.

Replace SolverImpl with

 a. A minimizer specific preprocessor class.
 b. A generic Solve function inside solver.cc
 c. Presummarize and Postsummarize functions to handle
    updates to the summary object.

The existing SolverImpl class was a mixture of the above three
things and was increasingly complicated code to follow. This change,
breaks it into its three separate constituents, with the aims of
better separation of concerns and thus better testability and
reliability.

The call to Solver::Solve() now consists of

1. Presummarize - summarize the given state of the problem and solver
   options.
2. Preprocess - Setup everything that is needed to call the minimizer.
   This includes, removing redundant parameter and residual blocks,
   setting up the reordering for the linear solver, creating the
   linear solver, evaluator, inner iteration minimizer etc.
3. Minimize.
4. Post summarize - summarize the result of the preprocessing and the
   solve.

Change-Id: I80f35cfc9f2cbf78f1df4aceace27075779d8a3a