Re: [Libmesh-devel] Nonlinear Solver Callbacks

[Roy S. <roy...@ic...>]

On Fri, 30 Apr 2010, Derek Gaston wrote:

> On Apr 30, 2010, at 1:14 PM, Roy Stogner wrote:
>
>       I went a little *too* OO with FEMSystem - in hindsight there should
>       have been a separate subclassable Physics object to attach which
>       included the residual evaluation functions, and requiring subclassing
>       of FEMSystem itself was more work and less flexible.
> 
> 
> Yeah - but all we're talking about here is an abstract base class that consists of:
> 
> class ProblemInterface
> {
> public:
>   virtual void residual() = 0;
>   virtual void jacobian() = 0;
> };
> 
> It's not going to be a huge burden...

Okay, I misunderstood what we were talking about then.  This is just
fine - it effectively *is* what I was calling a "functor" approach,
despite it not being a plain "overload operator()".  I thought you
were talking about requiring users to overload NonlinearSystem.

> About backward compatibility: come on!  This is adding _one_
> argument to _two_ functions.  Most codes will be able to fix this in
> 10 seconds!  We can change it and announce it on libmesh-users and
> it will be fine.  If users are upset about that small of a change...
> then they should be using a libMesh release instead of svn....

Fair enough.  I'll leave the decision up to Ben; he's the first person
I thought of who would be affected.
---
Roy