On Thu, Jun 18, 2009 at 4:42 PM, Roy Stogner<royst...@ices.utexas.edu> wrote:
>
> On Thu, 18 Jun 2009, Brent Kraczek wrote:
>
>> Please let me know if you want anything changed.
>
> We can ignore my criticisms if other developers disagree, but:
>
>
> Doing matrix-based norms in LinearImplicitSystem rather than in
> SparseMatrix doesn't make sense to me. Every LinearImplicitSystem
> user can use a new SparseMatrix easily, but the converse is not true.
Agree with Roy here.
> Calling:
> system.get_matrix("energy").energy_norm(*system.solution);
> is a little more involved than
> system.calc_sys_energy();
> but it would be a lot more flexible. At most, the latter call should
> be a nicely named pseudonym that calls the former.
Indeed.
> The only reason for I can see for the library rather than the user to
> manage creation of an energy matrix is if we want the library itself
> be able to make use of an energy norm. For example, we're now
> standardizing on "adjoint_solution" as a vector name just so that
> adjoint-based library infrastructure can know what it should access.
> Are there circumstances in which we'd want the library itself to call
> calc_sys_energy()?
>
>
> Your tmpVec is serial; better would be to clone() the input vector so
> as to avoid wasting memory when the input vector (e.g. the solution)
> is parallel. Best still would be to directly calculate v'*A*v without
> the temp vector, but that would require linear algebra package
> specific implementations.
Which I think is the right way to do it... whether we call it energy
or whatever else, this should be a method of SparseMatrix which takes
a NumericMatrix and returns a scalar. That way we do it once and for
all, and we do it efficiently with specialized code or fall back on a
generic implementation sitting in the base class.
BTW, sorry I never got back to you on why we call
libmesh_assert(this->closed()); at the beginning of operator=. Did
you ever determine if that was actually necessary...?
--
John
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