On Thu, Mar 08, 2012 at 09:53:48PM +0000, Garth N. Wells wrote: > > > On 8 Mar 2012, at 21:43, Johan Hake <[email protected]> wrote: > > > On Thu, Mar 8, 2012 at 9:40 PM, Garth N. Wells <[email protected]> wrote: > >> This change is not safe. For a matrix and a vector to be compatible in > >> parallel, it is not sufficient to check the global size. > > > > True. The logic is that a user need to provide a result vector with > > correct size and parallell structure. If not just pass an empty > > vector. The problem with always resizing the result is that one loose > > performance for iterative solvers using A.mult(x, y). > > > The only proper solution that I see is that a user is responsible > for making sure that the size is right and that the function do no > resizing. The change is a half-way house, so I think that it should > be reverted. The old code was safe, and the proper, efficient > alternative is that no resizing be done.
It should be possible to send in an empty vector and get automatic resize. -- Anders > Garth > > > > > Johan > > > >> Garth > >> > >> > >> > >> > >> ---------- Forwarded message ---------- > >> From: <[email protected]> > >> Date: 8 March 2012 20:31 > >> Subject: [Branch ~dolfin-core/dolfin/trunk] Rev 6630: Avoid > >> unnessesary resize of result vector for A.mult(x, y) > >> To: Garth Wells <[email protected]> > >> > >> > >> ------------------------------------------------------------ > >> revno: 6630 > >> committer: Johan Hake <[email protected]> > >> branch nick: work-trunk > >> timestamp: Thu 2012-03-08 21:25:41 +0100 > >> message: > >> Avoid unnessesary resize of result vector for A.mult(x, y) > >> -- Apply patch from Joachim > >> modified: > >> ChangeLog > >> dolfin/la/EpetraMatrix.cpp > >> dolfin/la/GenericMatrix.h > >> dolfin/la/PETScMatrix.cpp > >> dolfin/la/uBLASMatrix.h > >> dolfin/swig/la/post.i > >> test/unit/la/python/KrylovSolver.py > >> > >> > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
