Hi,
I do not use preconditioners for the surface integral formula, because it it
well-conditioned.
I tested several preconditoners, the convergence rates by using
precoditioners are more or less the same as the one without preconditioners.
Zhengyong
On Tue, May 10, 2011 at 11:48 AM, Danesh Daro
Hi,
Yes this is more or less what I am using, however in addition to surface
I use volume integrals too for current distributions. Well, I know that
condition number should be decreased in general to improve the
convergence, but can you please let me know what preconditioner did you
use? I have n
Yes, My problem is originally dense. That's why I used LAPACK to solve
the equation. After some sparsifications, when the problem becomes
sparse, I use sparse solvers. As I wrote, I have successfully used
direct sparse solvers using other packages and now I am moving to
iterative solvers using PET
HI?
I was working on solving Maxwell equations by surface integral approaches. If
you are working on this, try to decrease the condition numbers of your integral
operators so that it is reasonable to use GMRES solver in a limited number of
iterations, which is a need for applying fast multipole
On Mon, May 9, 2011 at 19:06, Danesh Daroui wrote:
> Thanks for the tip, but I already have two different version of my
> solver with PARDISO and MUMPS. Sparse Direct Solvers gave us a great
> contribution but I need to move to O(n^2) time complexity, So I really
> need to employ iterative solver
Hi,
Thanks for the tip, but I already have two different version of my
solver with PARDISO and MUMPS. Sparse Direct Solvers gave us a great
contribution but I need to move to O(n^2) time complexity, So I really
need to employ iterative solvers! :)
Regards,
D.
On Mon, 2011-05-09 at 19:01 +0200
On Mon, May 9, 2011 at 18:50, Danesh Daroui wrote:
> A direct solver? Never! :) I am escaping from time complexity of direct
> solvers, otherwise I already have a LAPACK based code that works well.
>
Sparse direct solvers are quite different. Scalability is still not optimal,
but it's not like f
On Mon, 2011-05-09 at 11:35 -0500, Barry Smith wrote:
> The code is very slow for one of two reasons
>
> 1) the matrix preallocation is not correct and it is spending a great deal of
> time in the MatSetValues() calls. To check this run the code with -info and
> grep the output for malloc. My gu
On Mon, May 9, 2011 at 18:29, Danesh Daroui wrote:
> No I didn't put "no-debugging" when I compiled. I will re-compile it. I
> am solving a set of Maxwell equations in integral form. I know that my
> coefficient matrix has a large condition number too. Would you please
> explain more about "-ksp_
Hi,
No I didn't put "no-debugging" when I compiled. I will re-compile it. I
am solving a set of Maxwell equations in integral form. I know that my
coefficient matrix has a large condition number too. Would you please
explain more about "-ksp_view" and "-log_summary"? How can I use these
options?
On Mon, May 9, 2011 at 18:02, Danesh Daroui wrote:
> it
> shouldn't be that slow! Am I right or I am missing something?
>
What equations are you solving? Did you build PETSc --with-debugging=0? Run
with -ksp_view -log_summary and send the output.
-- next part --
An HTML a
Hi again,
The issue is solved and it was due to a bug in my code. But now the
problem is that PETSc is extremely slow when I try to solve even a small
equation. I fill the matrix and right-hand-side and call the solver as
below:
ierr=KSPCreate(PETSC_COMM_WORLD, &ksp);
ierr=KSPSetOperators(ksp, M
The code is very slow for one of two reasons
1) the matrix preallocation is not correct and it is spending a great deal of
time in the MatSetValues() calls. To check this run the code with -info and
grep the output for malloc. My guess is that you are not preallocating for the
diagonal and
Hi,
I checked my code and there is no zero on the diagonal. I also modified the code
so if there is any zero on the diagonal it will be stored anyway. After this
change the problem still exists! I am not sure if I have called PETSc functions
correctly or in correct sequence. But anyway, it return
Dear PETSc users,
I have recently started to use PETSc in our code. As the first try, I
assemble the matrix row by row and then put each non-zero element in
each row into PETSc matrix. Then I start to solve the equation. I use
PETSc on a multi-core machine, so I will not use MPI in my program. I
Danesh,
Some of the PETSc solvers (like the default ILU) require that you put
entries on all the diagonal locations of the matrix, even if they are zero. So
you should explicitly put a 0 on the diagonal locations that have 0 and the
issue will go away.
Barry
On May 6, 2011, at 1:1
16 matches
Mail list logo
