libMesh/libmesh — pull request #271 by dschwen (2014-06-12 15:32:22+00:00)
Title: Tone down AutoDiff error reporting and make it switch-offable

In certain applications, such as ParsedFunction, derivatives are build proactively and may never be used. We silence all AutoDiff exceptions in that case to avoid confusing the user.
It is up to the user to verify that the derivatives of a ParsedFunction were build successfully.