Kirill Voronin kvoro...@labchem.sscc.ru writes:
But looking at
http://www.mcs.anl.gov/petsc/petsc-current/src/ksp/ksp/impls/bcgs/bcgs.c,
I see that there should be two for each iteration of do loop.
Can this 3-d call happen due to the monitoring routines?
Yes, -ksp_monitor_true_residual
Dave May dave.mayhe...@gmail.com writes:
This type of bizarre unexplainable behaviour usually indicates memory
corruption.
For example: an illegal read of write from an array.
I suggest you run your code through valgrind to rule this out.
Also, I would recommend you modify and annotate your
Luc Berger-Vergiat lb2...@columbia.edu writes:
Configure once with $PETSC_ARCH=arch-dbg, --with-debugging=1 and once
with $PETSC_ARCH=arch-opt, --with-debugging=0
Then you can switch environment variables approprately
Note: the environment variables have to influence the way your program
Chung-Kan Huang ckhua...@gmail.com writes:
Hi,
I am trying to output the matrix but when I looked at
PetscViewerSetFormat It doesn't seem to provide ways to output matrix in
CSR format.
Am I looking at the right place?
It is a (binary) CSR format. There is no standard CSR file format.
Chung-Kan Huang ckhua...@gmail.com writes:
Hi,
Does PETSc provide means for conversion between AIJ BAIJ.
Did you try MatConvert?
My matrix is created as AIJ because it makes life easy for most part of the
applications
Why does the assembly code know what format it is assembling? All the
siddhesh godbole siddhesh4godb...@gmail.com writes:
hello,
i am not able to initiate multiple processes through mpiexec , when i do
that, i get following error on example problems in ksp
iitm@iitm:~/Downloads/petsc-3.5.2/src/ksp/ksp/examples/tutorials$ mpiexec
-n 3 ex1
Assuming ex1 does
Matthew Knepley knep...@gmail.com writes:
Fieldsplit block preconditioners can be used on this type of matrix, but
success obviously depends on the
analytic character of the operators. In particular, if we assume that we
have great PCs for the diagonal,
then B is the most important variable,
Umut Tabak u.ta...@tudelft.nl writes:
Thx for the swift reply, well, you mean directly or iteratively? I
looked a bit more but I am not sure if that is possible iteratively or
not, I guess it is not since the character of the blocks on the diagonal
are not well suited to iterative solution
Matthew Knepley knep...@gmail.com writes:
I don't like this business of ISes holding pointers to other ISes. This
fundamentally
changes the model. The hashing sounds workable.
ISs are immutable and a reference would probably be held anyway, so I
don't think it's evil.
We also have to think
Colin McAuliffe cjm2...@columbia.edu writes:
I'd be interested in implementing this, I think I should have some time to
spend on it in a few weeks. I suppose the ISSubset function should
determine which ISs were used to make up a third IS? Can this be done by
having ISSum attach a list of
Colin McAuliffe cjm2...@columbia.edu writes:
Dear all, I have a four field problem with dof structure stored in a DM
shell. The matrix is a MatNest. This works fine except for when I try to
group fields.
Colin, MatGetSubMatrix_Nest does not implement the case of unions of
index sets. The
Eric Chamberland eric.chamberl...@giref.ulaval.ca writes:
Hi,
We are asking ourselves what would be the most efficient way to
create/do assembly/solve a problem involving a lumped matrix in PETSC?
Lumping frequently comes from reduced quadrature, so you could simply
use the reduced
Fande Kong fd.k...@siat.ac.cn writes:
Hi all,
I make a very simple code, but run into some error messages.
Code:
#include petsc.h
static char help[] = simple test.\n\n;
#undef __FUNCT__
#define __FUNCT__ main
int main(int argc,char **argv)
{
PetscMPIInt tag = 0;
Ghosh, Swarnava sghosh2...@gatech.edu writes:
Hello,
I am trying to install petsc 3.4.5 with Elemental 0.85 using the following
command:
./configure --with-cc=gcc --with-cxx=g++ --with-fc=gfortran
--download-f-blas-lapack=1 --download-mpich --download-cmake
Alp Kalpalp alpkalp...@gmail.com writes:
Thanks for the answers,
Jed, PCPG stands for Preconditioned
Acronyms like PCG were outdated before I was born, much like digital
computer. All Krylov methods in PETSc are preconditioned; let's not
contribute to meaningless acronyms.
Conjugate
Alp Kalpalp alpkalp...@gmail.com writes:
Thanks for the answers,
Please forgive me, I forgot to say that my stiffness matrix is not changing
during time steps. I could not remember directly but just after a google
search..I just hit this
Umut Tabak u.ta...@tudelft.nl writes:
Preconditioner side: my experience was that one should be really lucky
to get a good preconditioner which is really really rare, as mentioned,
especially for ill-conditioned problems, almost impossible. If my
condition number estimate is above, say, 1e4
Alp Kalpalp alpkalp...@gmail.com writes:
In FETI, system is replaced with a coarse problem of dual variables
Not a coarse problem (those are removed in the standard FETI-DP
formulation), but the Lagrange multipliers defining an interface
problem. BDDC is a primal version with the same
Christoph Pohl metal-gear-...@web.de writes:
Dear fellow PETSc users,
I've been trying to subtract one matrix from another, i.e. Y = Y - X, using
`call MatAXPY(Y, minus_one, X, SAME_NONZERO_PATTERN, ierr)`.
You can only use SAME_NONZERO_PATTERN pattern if the matrices have the
same nonzero
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
Dear petsc-users,
I'm trying to setup matrices and data structures for use with
MatGetLocalSubMatrix, but I'm rather lost in a world of ISes and block sizes.
I have the layouts and so forth correct where all my fields have block
Florian Lindner mailingli...@xgm.de writes:
Hello,
I have a piece of code that looks like that:
// PETSC_COMM_WORLD = MPI_COMM_WORLD;
PetscBool petscIsInitialized;
PetscInitialized(petscIsInitialized);
if (not petscIsInitialized) {
PetscErrorCode ierr;
std::cout
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
What is ISSetBlockSize for then? Just hanging information on the IS for use
elsewhere?
The index set would need to be contiguous:
static PetscErrorCode ISSetBlockSize_Stride(IS is,PetscInt bs)
{
IS_Stride *sub =
Gilles Steiner gilles.stei...@epfl.ch writes:
Hello Petsc Users,
I have an issue trying to use FiledSplitPC in parallel.
My goal : I want to get a linear system from petsc binary files and
solve this in parallel with the FieldSplitPC.
The problem I want to solve is an FE approximation of
paul zhang paulhuaizh...@gmail.com writes:
Jed,
I want to use CMake for a package that dependents on PETSc. It seems work
this morning.
Sounds like you're set. You can use my FindPETSc.cmake if you want.
signature.asc
Description: PGP signature
UK paulhuaizh...@uky.edu writes:
Hi All,
Does anyone have the experience of using cmake to get some out-of-source
libraries to work with PETSc? Your help is highly appreciated it.
Can you be more precise? You built some package and you want PETSc to
use it, or you want to use CMake for a
Lisandro Dalcin dalc...@gmail.com writes:
We can experiment in this code with some extra APIs to let users
specify the initial derivative. What about TSAlphaSetSolution(ts,U,V)
and TSAlphaGetSolution(ts,U,V), where U and V are the initial
solution and derivative vectors?
For multistep
Barry Smith bsm...@mcs.anl.gov writes:
Miguel,
Thanks for reporting this, you have found a bug in our code. When we
changed the adapt type we did not zero out the function pointers for the old
basic adaptor hence they were improperly called when the object was finally
destroyed at
Andrew Spott ansp6...@colorado.edu writes:
In the slepc and petsc docs, is there a way to tell if a function is going to
copy, modify, or just “look” at a petsc object that is a parameter?
Specifically there are two examples that I’m curious about (I’m trying to
chase down a bug):
Andrew Spott ansp6...@colorado.edu writes:
Thanks for the help regarding etags. I used to have them set up, I’ll have
to reconfigure them.
Actually, do call ESPSetOperators so that EPS knows….
Unfortunately this just confused me more. Am I reading this correctly in
that doing:
paul zhang paulhuaizh...@gmail.com writes:
Hi all,
I was wondering if PETSc has a point implicit method solver or similar
implemented.
-pc_type pbjacobi
signature.asc
Description: PGP signature
Alp Kalpalp alpkalp...@gmail.com writes:
Hi,
How to understand that I should reconfigure after a git pull?
It is usually not necessary, but may be necessary if changes in config/
are relevant to you. You can see the changes to config/ with
$ git pull
$ git log --stat ORIG_HEAD.. --
Sun, Hui hus...@ucsd.edu writes:
After reading some documentation, I figured it out myself. MATAIJ can
be MATSEQAIJ or MATMPIAIJ, depending on the number of processors
involved. Thus, I need to include the command
MatSeqAIJSetPreallocation as well, to cover both cases.
Or call
Young, Matthew, Adam m...@bu.edu writes:
Is there an advantage to using MatXAIJSetPreallocation (as Jed
suggested) or either of the SEQ/MPI preallocation routines (as Hui
originally considered) instead of calling MatSetUp to cover all cases?
If you don't preallocate, MatSetUp guesses:
Sun, Hui hus...@ucsd.edu writes:
Estimation of possible speedup of MPI programs based on Streams benchmark.
It appears you have 1 node(s)
Does this result basically says that my MacBook only have one node?
However, I know my computer has 4 cores, as I type sysctl -n hw.ncpu
in bash, it
Sun, Hui hus...@ucsd.edu writes:
Thank you Jed. I don't know how to use lstopo from the hwloc,
A search engine will solve that problem.
but I looked up the cores and memory from the hardware overview from
my MAC, it has
Number of Processors: 1
Total Number of Cores:2
Besides,
Luc Berger-Vergiat lb2...@columbia.edu writes:
Hi all,
I would like to know if there would be an easy way of computing the Sp
preconditioner for a fieldsplit schur complement using the following
formula:
Sp=A11-A10*diag(inv(A00))*A01
instead of
Sp=A11-A10*inv(diag(A00))*A01
Not in
Sun, Hui hus...@ucsd.edu writes:
Hello,
I try to use external packages such as umfpack or superlu, which are listed
here:
http://www.mcs.anl.gov/research/projects/petsc/documentation/linearsolvertable.html
I have PETSc compiled and installed with those external packages. Presumably
I
Jose E. Roman jro...@dsic.upv.es writes:
SLEPc is intended for large-scale eigenproblems, where you compute
only part of the eigenvalue/eigenvector pairs because
computing/storing all of them would be unaffordable. For small-medium
problems use LAPACK or ScaLAPACK.
Or Elemental
Bishesh Khanal bishes...@gmail.com writes:
Ok, I now see that KSPGetSolution(ksp, x) gives a GLOBAL vector in x and
not a local vector; hence the runtime memory error above since I can't
access ghost values in indices such as [i-1] wth the global vec.
Was there any reason not to make this
paul zhang paulhuaizh...@gmail.com writes:
Hi Jed,
Does this mean I've passed the default test?
It's an MPI test. Run this to see if PETSc solvers are running correctly:
make PETSC_DIR=/home/hzh225/LIB_CFD/nP/petsc-3.5.2 PETSC_ARCH=linux-gnu-intel
test
Is the open matplotlib an issue?
paul zhang paulhuaizh...@gmail.com writes:
Hi Jed,
Now I see PETSc is compiled correctly. However, when I attempted to call
petscksp.h in my own program (quite simple one), it failed for some
reason. Attached you can see two cases. The first is just the test of MPI,
which is fine. The
paul zhang paulhuaizh...@gmail.com writes:
Some error messages attached.
-- Detecting CXX compiler ABI info - done
CMake Error at
/share/cluster/RHEL5.4/x86_64/apps/cmake/2.8.4/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:91
(MESSAGE):
PETSc could not be found. Be sure to
paul zhang paulhuaizh...@gmail.com writes:
Like this? still in trouble though...
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
set(PETSC_DIR /home/hzh225/LIB_CFD/nP/petsc-3.5.2)
If you're going to manually set local paths in your build files, then
CMake is definitely a waste of time. These are
paul zhang paulhuaizh...@gmail.com writes:
Sounds like a warning, is it serious?
No, as explained in the message.
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes - Success
-- PETSc requires extra include paths, but
paul zhang paulhuaizh...@gmail.com writes:
Hello,
I compiled the newest version of petsc-3.5.2 and tried to test an example
code with it. I could managed the compilation, but as I ran the sample,
some error popped out. Could you please have a check? (files attached. I
did search the issue
Please keep the discussion on-list.
paul zhang paulhuaizh...@gmail.com writes:
I set some breakpoints, which shows the code breaks down at the
PetscInitialize(argc,argv,(char *)0,help);
Run in a debugger and send a stack trace. This is most likely due to a
misconfigured environment/MPI.
Derek Gaston fried...@gmail.com writes:
I am changing the stencil of my preconditioning matrix in the middle of a
solve a solve... and I'm running into this:
Can you PCReset() after changing the stencil?
The implementation of MatGetSubMatrices_MPIAIJ caches some intermediate
structures to
Derek Gaston fried...@gmail.com writes:
BTW: Ignore Jed's gibberish about PCReset(), you've got no business
messing with that.
Hah - will do. :-)
Yeah, my reply was premature and crappy. This should be handled
correctly without shenanigans.
signature.asc
Description: PGP signature
Kirill Voronin kvoro...@labchem.sscc.ru writes:
Hello!
Thanks Matthew Knepley and Barry Smith for the answers to my previous
questions!
I am solving Ax = b with PETSC BiCGStab with user-defined preconditioner
and want to compare it with other iteration process.
The question is
1)
Is
Barry Smith bsm...@mcs.anl.gov writes:
The only concern is that the user might not exceed that depth, so why
should they have to set an arbitrary and excessively big value?
We could check the value of the environmental variable and print the error
message when the error occurs and is
Håkon Strandenes haa...@hakostra.net writes:
My local HPC group have found a solution to this problem:
On MPT it is possible to set an environment variable MPI_TYPE_DEPTH with
default value 8. The MPI_TYPE_DEPTH variable limits the maximum depth of
derived datatypes that an application can
Gaetan Kenway gaet...@gmail.com writes:
The untransposed system converges about 6 orders of magnitude with
GRMES(100), ASM (overlap 1) and ILU(1) with RCM reordering. The test is run
on 128 processors. There are no convergence difficulties.
However, when I try to solve the transpose of the
Barry Smith bsm...@mcs.anl.gov writes:
On Nov 26, 2014, at 3:35 PM, Håkon Strandenes haa...@hakostra.net wrote:
Is it really PETSc's taks to warn about this? PETSc should trust HDF5 to
just work and HDF5 should actually print sensible warnings/error messages.
Shouldn't it?
Yes, but
Orxan Shibliyev orxan.shi...@gmail.com writes:
Hi
I have an unstructured grid formed with DMPLEX. There are several DOFs
associated with the grid such as density, pressure and so on. I would like
to view the densities (preferably with Tecplot) on each node. How can I do
that?
View with
Anush Krishnan k.an...@gmail.com writes:
And is it possible to generate an indefinite preconditioner from a
matrix that is symmetric positive definite (I remember seeing a thread
about this recently)?
See, for example, Kershaw's matrix in src/ksp/pc/examples/tutorials/ex1.c.
signature.asc
Welland, Michael J. mwell...@anl.gov writes:
I'm using PCFieldSplit with 2 fields, and sometimes the ksp solver for
one of those fields diverges. Is it possible to have it immediately
kill the outer ksp solver when this happens?
I can't think of a nice way. You could set a convergence test
Dave May dave.mayhe...@gmail.com writes:
PETSc team, seems the webpages
http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSeqAIJGetArray.html
http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSeqAIJRestoreArray.html
both contain a typo. The input matrix
Matthew Knepley knep...@gmail.com writes:
These are very new, so there could be bugs lurking. It would help our
testing if this is
reproducuble on a standard example. Does this happen if you try to solve
KSP ex2
or SNES ex5 with PIPECG?
I can reproduce. PIPECG has evidently been broken
Sascha Schnepp m...@saschaschnepp.net writes:
The issue could be related to this code in
KSPCreate_PIPECG
ierr =
KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_LEFT,2);CHKERRQ(ierr);
ierr =
KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_LEFT,2);CHKERRQ(ierr);
ierr =
Harshad Sahasrabudhe hsaha...@purdue.edu writes:
Hi,
I want to implement a Predictor-Corrector algorithm for solving a coupled
Schrödinger-Poisson system using SNES. I can calculate the next step using
my predictor algorithm and don't want PETSc to calculate the next step. I
only need PETSc
Fande Kong fd.k...@siat.ac.cn writes:
Hi all,
If I do a matrix assembly with the flag MAT_FLUSH_ASSEMBLY, will it involve
any communications across processors?
Yes, that's the point of this assembly mode. You call it to flush the
stash of values that need to be sent to other processes, to
De Groof, Vincent Frans Maria vincent.de-gr...@uibk.ac.at writes:
Dear all,
I am writing a few variations on the PCG algorithm. Starting with my own PCG
implementation, I noticed that my routine is quite a bit slower (~20%). I
think I tracked it down to the MatSolve calls in PCApply. I am
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
So is the problem that the nullspace belongs to the appropriate
operator, but at the point you tell the solver, you don't necessarily
have all the operators to hand? Moreover, depending on the PC choice,
the nullspaces of the operator
Barry Smith bsm...@mcs.anl.gov writes:
Perhaps we need a generic way of attaching null spaces to parts of
matrices and to parts of matrices in different basis (which is what
a Schur complement is). So (and this is likely overly simplistic)
one could supply a null space, an index
Barry Smith bsm...@mcs.anl.gov writes:
Indeed it could. Perhaps we could start by unifying the concept of a
sub matrix and a Schur complement of the same part of the matrix?
I'm not sure how to do that.
We can certainly define an interface that works this way, but I'm not
sure it's
Dmitry Karpeyev karp...@mcs.anl.gov writes:
I think the problem-specific solver configuration can be carried out by an
additional user-specified callback (attached, e.g., using PCSetUserSetUp())
called from PCSetUp().
The problem of propagating it down the hierarchy can be solved by using DMs
Kirill Voronin kvoro...@labchem.sscc.ru writes:
Hello everyone!
Can anyone help with the following question - if I am solving a symmetric
SLAE (both structure and values), is it possible to store only the upper
trinagular part of the matrix and apply all PETSC routines like KSPsolve
etc.?
Filippo Leonardi filippo.leona...@sam.math.ethz.ch writes:
I'm stupid: somehow I was in master and didn't notice that. Sorry for the
confusion.
The branch 'mark/ksp-zero-eig' has been merged to 'master' now.
signature.asc
Description: PGP signature
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
OK, so it's sounds like this is probably a deliberate choice. I note that
the code currently does this:
fieldsplit.c:703
ierr = MatSetFromOptions(jac-schur);CHKERRQ(ierr);
ierr = MatGetNullSpace(jac-pmat[1],
Matthew Knepley knep...@gmail.com writes:
at which point the nullspace is not attached, no?
Crap, that is right. I think we should propagate the nullspace from pmat[1].
Uh, there is no reason pmat[1] can be expected to have the same null
space. pmat[1] is the zero matrix in some important
吕超 luc...@mail.iggcas.ac.cn writes:
Dear all,
Now, I need create a big matrix, but only some rows have values,
other rows are all 0. The spy of the matrix looks like the
figure below.
You can create a matrix like this, but the default distribution is for
balancing rows.
Miguel Arriaga miguelarriagaecu...@gmail.com writes:
Hi there,
I have a matrix shell where the Mult operation looks like this:
y=1/2(K+K*) x
with K=M^-1 A and K* its transpose.
1- For setting-up the operation MatMult, since I need to do a KSPSolve on
M, should I set-up the KSP on the
Miguel Arriaga miguelarriagaecu...@gmail.com writes:
Hi,
Thank you so much for your reply.
1
One note that I forgot to mention is that I'm using FORTRAN (sorry!).
Is it possible to set up the context to pass M and the ksp for M? I also
try to avoid common blocks but in this case it seemed
Florian Lindner mailingli...@xgm.de writes:
I'm more or less aware of that, but I'm surprised that the performance is
such poor.
If you've ever written a naive triply-nested loop dgemm, you'd know that
it gives up orders of magnitude.
I changed the format of matrixC to dense now, but the
Evan Um eva...@gmail.com writes:
Dear PETSC users,
I hope that I can have a comment about errors I got during sparse symmetric
matrix construction. In this example, I used three processes. The size of a
test matrix is 52105-by-52105. The length of array d_nnz and o_nnz is 17461
at rank 0,
Evan Um eva...@gmail.com writes:
Dear Jed,
Thanks for your help many times. These numbers mean the total number of
elements to be added using MatSetValues(). For example, at process 0,
148767+5821 elements are added to matrix B. In other words, the length of
arrays (i.e.
Evan Um eva...@gmail.com writes:
Dear Jed,
In my problem, each process has a part of contiguous rows of matrix B. In
this partitioned matrix, locations of non-zero elements are irregular
because it is a part of unstructured matrix. It is hard to define the
distribution of a vector that the
Filippo Leonardi filippo.leona...@sam.math.ethz.ch writes:
Sorry for the late update.
I tested the code with the branch:
ksp-zero-eig
But the problem seems to still be there, also tried:
-ksp_chebyshev_estimate_eigenvalues_random
but does not change.
These are probably on levels, like
Norihiro Watanabe norihir...@gmail.com writes:
as far as I read http://www.vtk.org/VTK/img/file-formats.pdf, there is no
comment marker in ASCII VTK format.
Note that for any use beyond the simplest debugging, you should use the
VTK XML formats of PETSCVIEWERVTK. Write to *.vtr or *.vts for
Barry Smith bsm...@mcs.anl.gov writes:
I've tried to use a direct solver like suggested on pp 72, but:
./petBench 600 1 -ksp_type preonly -pc_type lu
You cannot use LU with SBAIJ format. Only Cholesky. So use -pc_type cholesky
And using a sparse matrix format for a dense matrix is a
Gautam Bisht gbi...@lbl.gov writes:
Hi Jed,
On Thu, Oct 30, 2014 at 9:22 PM, Jed Brown j...@jedbrown.org wrote:
Gautam Bisht gbi...@lbl.gov writes:
All,
While running src/ts/examples/tutorials/ex8.c (in PETSc 3.5.1) for TSTYPE
sundials and pseudo, I noticed that the solver
Gautam Bisht gbi...@lbl.gov writes:
All,
While running src/ts/examples/tutorials/ex8.c (in PETSc 3.5.1) for TSTYPE
sundials and pseudo, I noticed that the solver overshoots the final time.
Is this what you're looking for?
Mengqi Zhang joll...@gmail.com writes:
It seems that the parallel running doesn't work, the elapsed time is
roughly the same.
http://www.mcs.anl.gov/petsc/documentation/faq.html#computers
You see that in the process of assembling the matrix in the parallel
case, the two cores are working
Evan Um eva...@gmail.com writes:
PETSC users,
As memory is at a premium in my problem, I want to compute only the upper
triangular elements of a matrix and then construct a parallel sparse
symmetric matrix. In this case, do I have to use MatSetOption
Mark Adams mfad...@lbl.gov writes:
OK, so the first time there is no RHS and so not eigen estimate and the
next solves do not check to see if a valid eigen estimate has been created.
I think so. I'm hoping Filippo will confirm.
Jed: could we just check for zero iterations in the eigen
Miguel Angel Salazar de Troya salazardetr...@gmail.com writes:
Sorry to be pushy, but could anyone help me on this?
Your last email didn't have a specific question, so I'm not sure how to
answer. What you want to do is possible, but not trivial and might
require library modifications to avoid
Matthew Knepley knep...@gmail.com writes:
On Tue, Oct 28, 2014 at 10:34 AM, Rongliang Chen rongliang.c...@gmail.com
wrote:
Hello,
I have a very elementary question. I am trying to learn the PETSc finite
volume method codes. Can you tell me which book did you refer to for the
PETSc FVM?
Rongliang Chen rongliang.c...@gmail.com writes:
Thanks Matt and Jed,
I am trying to write a parallel FVM code on unstructured grid for
compressible NS equations. I found that the finite volume code on the
structured mesh is easy to write but for the unstructured mesh, it is
really
Tabrez Ali st...@geology.wisc.edu writes:
Matt and Jed
But it does appear to work well in practice (as in I get the correct
solution).
Your correct solution has a residual seven orders of magnitude bigger
than the initial guess. Does that not give you pause?
signature.asc
Description:
Rongliang Chen rongliang.c...@gmail.com writes:
Hi Jed,
I am solving the 3D compressible Navier-Stokes equations. I have read
the ex11.c for several days and still do not fully understand this. I
will look at the older version as you suggested. Maybe I need to go to
your office to ask
Tabrez Ali st...@geology.wisc.edu writes:
Jed
You're right and it is precisely what I am trying to understand as well.
I am attaching the comparison to the analytical solution. As you can see
the agreement is almost perfect, except at the discontinuity (y=0 in the
analytical solution).
Rongliang Chen rongliang.c...@gmail.com writes:
Yes. I am at CU Boulder. I will read the Berger paper first, and then if
possible, I will go to your office to talk with you when you are free.
I can meet before 5pm this afternoon or tomorrow any time other than 12-1pm.
Note that the example
Sharp Stone thron...@gmail.com writes:
Hi Matt,
Thank you very much for your reply.
The ts_view output is attached below. I found my code results say SNES has
not been set up, and PC has not been set up. Does this cause the
problem? If so I do not see example ex17 explicitly set up the
Barry Smith bsm...@mcs.anl.gov writes:
On Oct 23, 2014, at 1:32 AM, Filippo Leonardi
filippo.leona...@sam.math.ethz.ch wrote:
Tested on this branch: the program no longer crashes, but the solution is
actually still wrong.
Yes, we never said that this fixed the problem.
Jed ?
Sharp Stone thron...@gmail.com writes:
Hi Matt,
That is why we asked this. We do not think the calculation of DAE
F-functions are wrong. But even if the F-functions are not accurate, we
expect the TS solver would still call TSSetIJacobian(), but actually it
does not call TSSetIJacobian()
Filippo Leonardi filippo.leona...@sam.math.ethz.ch writes:
-ksp_chebyshev_estimate_eigenvalues_random
Can try this but the problem, to me, seems deeper (because inherited from
each
solve afterwards).
Are you changing the operator between solves? Or just solving different
right-hand sides?
Florian Lindner mailingli...@xgm.de writes:
Hello,
I am redoing an radial basis function interpolation algorithm using petsc in
our software.
Using basis function with compact carrier is blazingly fast. These basis
function result in sparse matrices.
ierr = MatSetType(matrixC,
Arne Morten Kvarving arne.morten.kvarv...@sintef.no writes:
thanks for educating me! i wasn't aware richardson could break definiteness.
This is usually caused by the Richardson parameter being too aggressive.
An analogous breakdown occurs with Chebyshev when the eigenvalue
estimate is too
Arne Morten Kvarving arne.morten.kvarv...@sintef.no writes:
On 23/10/14 15:53, Jed Brown wrote:
hi jed,
Arne Morten Kvarving arne.morten.kvarv...@sintef.no writes:
Do you mean if the matrix is _not_ marked SPD? Interestingly, CG is
no i mean to warn if the matrix is marked SPD, main KSP
Barry Smith bsm...@mcs.anl.gov writes:
It is any interesting question if there is anything one can “do” to
a preconditioner to insure that it is SPD or detect if it may not
be BEFORE actually running the CG with that preconditioned.
You can use an eigensolver for the extreme
1201 - 1300 of 3946 matches
Mail list logo
