On Wed, Nov 4, 2009 at 2:06 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> > This is tricky because some C/C++ compilers long double uses 128 bits of > space but actually (on Intel) only uses 80 of the bits (those are the bits > that floating point unit handles). So you do not really get 128 bits. Also > MPI may not properly handle the 128 bit doubles. > I figured that his types were just C++ types once he said they were provided by a package. > I am investigating qd now. Is there any MPI implementation that uses qd? > Do you need MPI? > Can't we just make a type the correct number of bytes long? Matt > Barry > > > > On Nov 4, 2009, at 1:33 PM, Matthew Knepley wrote: > > If you are alright with EVERYTHING running with that, it already works. >> Just set PetscScalar >> to that type. I would help you setup a configure switch for it if needed. >> >> If you only want it for some operations, we would have to hear more >> specifics. >> >> Thanks, >> >> Matt >> >> On Wed, Nov 4, 2009 at 10:45 AM, Todd Munson <tmunson at mcs.anl.gov> wrote: >> >> Barry and Matt, >> >> I was wondering how hard it would be to modify PETSc to support >> double-double and quad-double arithmetic using the QD package >> from LBL? >> >> Its looking more and more likely that I may need this functionality for >> some upcoming projects that have bad scaling issues and I don't want to have >> to reimplement KSP and PC methods... >> >> Cheers, Todd. >> >> >> >> >> -- >> 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20091104/eb82322e/attachment.html>