Fande Kong writes:
> (1) The snes can solve my nonlinear problem with a default Jacobian
> provided in the Petsc using finite differences, but this method may cause
> some new nonzero allocations for the preallocated matrix.
Why are there new nonzeros? This must mean preallocation was incorrect
Hi all,
(1) The snes can solve my nonlinear problem with a default Jacobian
provided in the Petsc using finite differences, but this method may cause
some new nonzero allocations for the preallocated matrix.
(2) A Matrix-free version of snes also works well for my nonlinear problem,
but it does n
The phase-field system developed by Michael Tonks (copied on this email)
will be part of the open-source release of MOOSE (hopefully by the end of
next week). Feel free to contact either myself or Mike for more
information while we all wait...
In the meantime you can also check out some of the yo
Christophe Ortiz writes:
> Hi all,
>
> Recently I have implemented a 1D problem of coupled diffusion equations
> using PETSc. I did it using finite differences for diffusion terms and
> F(t,U,U_t) = 0. It works pretty well with ARKIMEX3. I get a nice timestep
> variation and all boundary conditio
Åsmund Ervik writes:
> We're talking about adding a refined level-set grid method
> (M. Herrmann, doi:10.1016/j.jcp.2007.11.002) to our code. Currently we
> solve two-phase Navier-Stokes (ghost fluid method) together with a
> standard level-set approach on a uniform Cartesian grid.
>
> What we're
On Fri, Feb 21, 2014 at 12:34 PM, Chung-Kan Huang wrote:
> Hello,
>
> In my application I like to use
> PetscErrorCode KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure
> flag)
> and have Pmat different from Amat
>
> if Amat = L + D + U
> then Pmat = Amat - L* - U* + rowsum(L* + U*)
> wher
On Feb 21, 2014, at 2:41 PM, Chung-Kan Huang wrote:
> Hello,
>
> In my application I like to use
> PetscErrorCode KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure flag)
> and have Pmat different from Amat
>
> if Amat = L + D + U
> then Pmat = Amat - L* - U* + rowsum(L* + U*)
> where
Barry,
Thanks for your time. I have a better understanding now.
Greg
>-Original Message-
>From: Barry Smith [mailto:bsm...@mcs.anl.gov]
>Sent: Friday, February 21, 2014 4:48 PM
>To: Fischer, Greg A.
>Cc: petsc-users@mcs.anl.gov
>Subject: Re: [petsc-users] partial stencil in DMDA?
>
>
>
On Feb 21, 2014, at 2:42 PM, Fischer, Greg A. wrote:
> Barry,
>
> If I'm interpreting correctly, the 2nd case would work fine for me. However,
> perhaps I was previously over-complicating the problem. Could I not just:
>
> 1. create a DMDA
> 2. create a global vector with DOF=1
> 3. call VecD
On Fri, Feb 21, 2014 at 3:28 PM, Barry Smith wrote:
>
> Though ml does support 64 bit integers for long vectors they do it in a
> fundamentally different way than PETSc; only certain integer data is stored
> in 64 bit form while most integer values are stored in 32 bit integers. In
> PETSc we m
Barry,
If I'm interpreting correctly, the 2nd case would work fine for me. However,
perhaps I was previously over-complicating the problem. Could I not just:
1. create a DMDA
2. create a global vector with DOF=1
3. call VecDuplicateVecs() against the DOF=1 global vector for my other ~100
DOFs
Hello,
In my application I like to use
PetscErrorCode KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure flag)
and have Pmat different from Amat
if Amat = L + D + U
then Pmat = Amat - L* - U* + rowsum(L* + U*)
where L* and U* is a portion of L and U and rowsum(L* + U*) will add into D
I k
Hello,
In my application I like to use
PetscErrorCode KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure flag)
and have Pmat different from Amat
if Amat = L + D + U
then Pmat = Amat - L* - U* + rowsum(L* + U*)
where L* and U* is a portion of L and U and rowsum(L* + U*) will add into D
I k
Though ml does support 64 bit integers for long vectors they do it in a
fundamentally different way than PETSc; only certain integer data is stored in
64 bit form while most integer values are stored in 32 bit integers. In PETSc
we manage all integers as either 32 or 64 bit so mixing the two
Greg,
The general mechanism for moving elements of vector between processes is
with VecScatterCreate() and VecScatterBegin/End() with it you can indicate
exactly what values are to move and to where, but it is all based on “one
dimension” indexing into the vector.
DMDA provides a
Hello everyone,
When I compile petsc with options -with-64-bit-indices and ml packages, I
got the error like this: "Cannot use ml with 64 bit integers, it is not
coded for this capability".
If I want to use ml as a preconditioner for long vectors (> 2 billions), is
there any solution?
Thank you
Barry,
Thanks! I have another question. The user manual says:
PETSc currently provides no container for multiple arrays
sharing the same distributed array communication; note, however, that the dof
parameter handles many cases of interest.
In my application, each space l
On Feb 21, 2014, at 11:02 AM, Fischer, Greg A.
wrote:
> Hello,
>
> I’m interested in using PETSc to manage distributed arrays. Based on my
> reading about the DMDA objects, I see that ghost points can be communicated
> in box-type stencils or star-type stencils.
>
> For my application, as
Hello,
I'm interested in using PETSc to manage distributed arrays. Based on my reading
about the DMDA objects, I see that ghost points can be communicated in box-type
stencils or star-type stencils.
For my application, assume that I have a 2D DMDA object with star-type
stencils. For a typical
19 matches
Mail list logo
