PETSc sparsity

[Mark Adams]

Just a note, my way is much simpler - its two lines of code in a loop  
over the boundary nodes, followed by an MatAsseblyBegin/End, and you  
don't have to deal with parallel issues explicitly - PETSc does.  For  
my FE codes the cost of this (dumb) way is negligible, PETSc  
implements these methods pretty well.

Mark

On Jun 15, 2007, at 4:28 PM, Toby Young wrote:

>
>
> Barry,
>
> Thank you for an interesting response.
>
>>   For algorithms that require dealing with the sparsity structure of
>> the matrix we generally just include the appropriate private  
>> include file
>> for the matrix format and access the data directly in the  
>> underlying format.
>
> Can you please elaborate. What do you mean by "the appropriate privat
> include file for the matrix"? Sorry, I got lost there.
>
> Best,
> 	Toby
>
> -----
>
> Toby D. Young (Adiunkt)
> Department of Computational Science
> Institute of Fundamental Technological Research
> Polish Academy of Science
> Room 206, ul. Swietokrzyska 21
> 00-049 Warszawa, POLAND
>

**********************************************************************
Mark Adams Ph.D.                                   Columbia University
289 Engineering Terrace                                        MC 4701
New York NY 10027
adams at pppl.gov                                www.columbia.edu/~ma2325
voice: 212.854.4485                                  fax: 212.854.8257
**********************************************************************