...@mcs.anl.gov [petsc-users-boun...@mcs.anl.gov] on
behalf of Barry Smith [bsm...@mcs.anl.gov]
Sent: Thursday, July 23, 2015 6:13 AM
To: Lawrence Mitchell
Cc: petsc-users@mcs.anl.gov
Subject: Re: [petsc-users] Null space/Near null space
On Jul 23, 2015, at 3:42 AM, Lawrence Mitchell
--
From: petsc-users-boun...@mcs.anl.gov [petsc-users-boun...@mcs.anl.gov] on
behalf of Barry Smith [bsm...@mcs.anl.gov]
Sent: Thursday, July 23, 2015 6:13 AM
To: Lawrence Mitchell
Cc: petsc-users@mcs.anl.gov
Subject: Re: [petsc-users] Null space/Near null space
On Jul 23, 2015, at 3
On Jul 23, 2015, at 3:42 AM, Lawrence Mitchell
lawrence.mitch...@imperial.ac.uk wrote:
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On 22/07/15 23:57, Barry Smith wrote:
If your matrix has a null space you should always be setting
MatSetNullSpace.
If you know the near null
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On 22/07/15 23:57, Barry Smith wrote:
If your matrix has a null space you should always be setting
MatSetNullSpace.
If you know the near null space then you should also always set it
(it cannot do any harm) because some preconditioners can
Should I be using MatSetNearNullSpace (as opposed to MatSetNullSpace) with
-pc_type hypre -pc_hypre_type boomeramg since BoomerAMG is multigrid?
--Matt
--
Matthew Young
Graduate Student
Boston University Dept. of Astronomy
Young, Matthew, Adam m...@bu.edu writes:
Should I be using MatSetNearNullSpace (as opposed to MatSetNullSpace) with
-pc_type hypre -pc_hypre_type boomeramg since BoomerAMG is multigrid?
As far as I know, Hypre doesn't directly use either of these.
MatSetNullSpace is for an actual null space.
If your matrix has a null space you should always be setting MatSetNullSpace.
If you know the near null space then you should also always set it (it cannot
do any harm) because some preconditioners can take advantage of it.
I do not think PETSc currently has code that transfers near
