[petsc-users] RAM usage by a sparse matrix

[Alexander Goncharov]

Thank you, Matt!

On Thu, 2012-08-09 at 19:16 -0500, Matthew Knepley wrote:
> On Thu, Aug 9, 2012 at 3:19 PM, Alexander Goncharov
> <alexvg77 at gmail.com> wrote:
>         Hello PETSC developers!
>         
>         I would like to ask a couple of questions about symmetric
>         sparse matrix
>         storage
>         
>         1. Is matrix frees unused preallocated nonzero space. For
>         example, when
>         run with option -info, it says how many nonzeros were unused.
>         Is this
>         unused space unallocated?
> 
> 
> Yes, during assembly.
>  
>         2. How PETSC stores symmetric sparse matrices on a GPU? Does
>         it stores
>         only half of it or not?
> 
> 
> We do not have symmetric storage on the GPU since we only have what
> the CUDA libraries have.
> 
> 
>    Matt
>  
>         Thank you!
>         
>         Alexander.
>         
> 
> 
> 
> 
> -- 
> 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