[petsc-dev] I do not think this is the right solution

[Matthew Knepley]

On Sun, Mar 18, 2012 at 11:52 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Mar 18, 2012, at 11:39 AM, Matthew Knepley wrote:
>
> > https://bitbucket.org/petsc/petsc-dev/changeset/7ae47bfbd6e9
> >
> > Why are we using the assembled flag to determine whether garray and
> colmap
> > should be created? That seems like an abuse of the flag. Shouldn't we
> check
> > for these when we need them?
>
>    This has always been the use of that flag since day one. That is the
> reason for the existence of that flag. Now you want to change the meaning
> of the flag.
>
>   Since your MatGetRow() MatSetValues() paradigm only works properly if no
> new nonzeros are introduced (otherwise people will get assembled errors
> after they've put in some values) what is wrong with my proposed solution
> of MatGetRowWrite() which is the correct interface for changing some values
> in the row but not the nonzero structure.


Your own metric. It complicates the interface. I have to know that I only
want to change existing nonzeros, when it is
perfectly easy for SetValues() to detect this AND I already went and found
all the places where this happens.

   Matt


>
>   Barry
>
> >
> >    Matt
> >
> > --
> > What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> > -- Norbert Wiener
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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