From: David Fuentes <fuentesdt@gm...>  20100518 14:46:26

On Tue, 18 May 2010, Roy Stogner wrote: > > On Mon, 17 May 2010, David Fuentes wrote: > >> Can the >> >> src/systems/implicit_system.C >> ImplicitSystem::qoi_parameter_hessian_vector_product >> >> routine be used > > Unfortunately the answer is probably "no" right here  the forward and > adjoint sensitivity methods are passing verification benchmark tests > right now, but the hessian is failing and the hessian_vector_product > hasn't been tested yet. Thanks Roy, I've always wondered where are the libMesh regression tests stored? Are they available to the public? For verification benchmarks of my adjoint hessian, I am currently 1) comparing adjoint gradient against finite difference gradient 2) comparing sensitivity gradient against adjoint gradient 3) and finally comparing adjoint hessian calculations against finite difference of the gradient to compute the hessian Are there any other verfication benchmarks are you currently finding useful? > >> w/ a time dependent system where you need to store the >> entire solution history for the state variable, 1st adjoint problem, and >> the linear combination of the "weighted" sensitivity to form the hessian >> vector product? > > And this answer is definitely "no". Right now adjoint_solve() assumes > you're solving a steady system. > >> In what data structures would you store the solution history? > > Not sure yet (which is part of the reason for that second "no"). For > large systems with implicit solvers the best thing to do is to write > and read (asynchronously) to disk. For smaller implicit systems we'd > want to keep the whole thing in memory. We're not planning on any > (efficient) support for explicit systems. What did you have in mind for this ? For smaller implicit systems, I have my own (hacked) version of your TransientSystem Class where I created a (class member) std::vector of NumericVectors to store the data. Solving heat equation, I run out of memory pretty quick for larger number of time steps. df >  > Roy > 