Delete unsupported autodiff
On Mon, Jul 28, 2014 at 01:40:53AM -0400, Bob Carpenter wrote:
> The big problem with using Eigen directly is that it doesn't
> support mixed types (double and autodiff var) in its matrix operators.
> And you really don't want to autodiff the algorithms themselves
> if you don't have to --- a lot of the linear algebra operations have
> analytic gradients (as do the matrix operators).