tree 798d6a218a068fcdbe2f7f49c2ed9a9770b5a45a
parent 3b1ad31a1fe89fe0bd78e1fffdf22d47d43faaf5
author Sameer Agarwal <sameeragarwal@google.com> 1386091694 -0800
committer Sameer Agarwal <sameeragarwal@google.com> 1386097104 -0800

Restore the state of the Problem after a call to Evaluate.

Calling Problem::Evaluate mutates the state of the parameter blocks.
In particular, depending on the set and order of parameter blocks
passed to the evaluate call, it will change the internal indexing
used by the Program object used by ProblemImpl. This needs to be
undone before Evaluate returns, otherwise the Problem object
is in an invalid state.

To help with testing and debugging in the future, a new method
Program::IsValid has been added which checks whether the problem
has its parameter and residual blocks in the right state.

Thanks to Stefan Leutenegger for reporting this.

Change-Id: I209b486a31433f0cbb58b570047649eca6d42b56