Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Kirk, Benjamin (JSC-EG311)
>>> That's good to keep in mind. PETSc performance (at least in the older >>> versions where I've made this mistake) becomes atrocious if it's asked >>> to create new non-zero matrix entries on the fly without >>> preallocation. >> >> Presumably MatMatMult in PETSc (or the equivalent in trilinos)

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Roy Stogner
On Mon, 17 Sep 2012, David Knezevic wrote: > On 09/17/2012 01:33 PM, Roy Stogner wrote: >> That's good to keep in mind. PETSc performance (at least in the older >> versions where I've made this mistake) becomes atrocious if it's asked >> to create new non-zero matrix entries on the fly without >

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread David Knezevic
On 09/17/2012 01:33 PM, Roy Stogner wrote: > On Mon, 17 Sep 2012, John Peterson wrote: > >> On Mon, Sep 17, 2012 at 8:42 AM, Andrew E Slaughter >> wrote: >>> I need to multiply two SparseMatrix objects together, in parallel, does >>> libMesh have this functionality? >>> >>> One possible solution

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Roy Stogner
On Mon, 17 Sep 2012, John Peterson wrote: > On Mon, Sep 17, 2012 at 8:42 AM, Andrew E Slaughter > wrote: >> I need to multiply two SparseMatrix objects together, in parallel, does >> libMesh have this functionality? >> >> One possible solution is to use the PETSc MatMatMult function, but this >>

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread John Peterson
On Mon, Sep 17, 2012 at 8:42 AM, Andrew E Slaughter wrote: > I need to multiply two SparseMatrix objects together, in parallel, does > libMesh have this functionality? > > One possible solution is to use the PETSc MatMatMult function, but this > requires that I use PetscMatrix objects, which I als

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Roy Stogner
On Mon, 17 Sep 2012, Derek Gaston wrote: > While that is probably true... we should probably enhance the SparseMatrix > interface to handle mat*mat cases... maybe Andrew would be willing to > supply a patch?! ;-) I'd be thrilled to see that. PetscMatrix does give easy access to the PETSc Mat,

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Derek Gaston
While that is probably true... we should probably enhance the SparseMatrix interface to handle mat*mat cases... maybe Andrew would be willing to supply a patch?! ;-) Derek On Mon, Sep 17, 2012 at 8:48 AM, Kirk, Benjamin (JSC-EG311) < benjamin.kir...@nasa.gov> wrote: > Check the PETSC matrix libm

Re: [Libmesh-users] SparseMatrix multiplication.

2012-09-17 Thread Kirk, Benjamin (JSC-EG311)
Check the PETSC matrix libmesh documentation - I think there is a method to return the raw PETSC object. I know there is for vectors anyway! -Ben On Sep 17, 2012, at 9:42 AM, "Andrew E Slaughter" wrote: > I need to multiply two SparseMatrix objects together, in parallel, does > libMesh ha