Here is ts_view.
On Tue, Jun 2, 2015 at 2:40 PM, Barry Smith bsm...@mcs.anl.gov wrote:
Run for one time-step with -ts_view so we can see exactly what solver
options you are using.
Then run with the additional options -ksp_pc_side right
-ts_max_snes_failures -1
On Jun 2,
Dear all,
I need to evaluate the max and min eigenvalues of a matrix when I make the
Chebyshev polynomial approximation. Are there efficient ways to do this?
Thank you very much.
Xujun
http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
On Jun 2, 2015, at 2:38 PM, Tuan Nguyen tuan.v...@gmail.com wrote:
Thanks Matt!
It works now but there is issue of memory occur:
PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably
memory access out
Ok, now use a real integrator with adaptive timestep selection. I suggest
the additional options
-ts_type arkimex -ts_arkimex_fully_implicit -ts_adapt_monitor
but Emil and Jed will know much better than me.
Barry
On Jun 2, 2015, at 12:51 PM, Italo Tasso it...@tasso.com.br wrote:
I originally solve that example problem using LU. But when I solve this one:
http://fenicsproject.org/documentation/dolfin/1.5.0/python/demo/documented/stokes-iterative/python/documentation.html
By simply running their code as is for TH and adding the one like I
mentioned for MTH, I get the
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
Maybe Justin can chime in here, I don't know, I just happened to know
how the fenics implementation produces the basis, so proffered that.
Thanks, Lawrence. Unfortunately, my original questions remain
unanswered and now I'm doubly
Thanks Matt!
It works now but there is issue of memory occur:
PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably
memory access out of range
[3]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[3]PETSC ERROR: or see
Xujun Zhao xzha...@gmail.com writes:
I need to evaluate the max and min eigenvalues of a matrix
You need the min and max eigenvalues of the preconditioner operator.
But note that Chebyshev is not usually used as a stand-alone solver, but
rather as a smoother for multigrid or occasionally as a
On Tue, Jun 2, 2015 at 3:55 PM, Harshad Sahasrabudhe hsaha...@purdue.edu
wrote:
Hi,
Does PETSc have automatic differentiation capability? I'm solving an
elliptic non-linear equation in which calculating the correct Jacobian is
extremely demanding. The system doesn't converge with an
On Tue, Jun 2, 2015 at 4:05 PM, Harshad Sahasrabudhe hsaha...@purdue.edu
wrote:
I haven't tried the FD Jacobian. How do I enable that? I have been
providing the Jacobian.
Just do not provide the Jacobian. It will turn on.
Thanks,
Matt
On Tue, Jun 2, 2015 at 4:59 PM, Matthew
MTH did not converge with the default -ksp_rtol 1e-6 so I had to raise the
tolerance to 1e-5 in order to get a solution. Attached are the outputs for
TH and MTH
Last one with the svd did not work with the way the AMG PC was hard-coded
into FEniCS. Here's the list of preconditioners my
Justin Chang jychan...@gmail.com writes:
I originally solve that example problem using LU.
I'd like to learn why LU didn't notice that the system is singular.
(The checks are not reliable, but this case should be pretty obviously
bad.)
But when I solve this one:
Hi,
Does PETSc have automatic differentiation capability? I'm solving an
elliptic non-linear equation in which calculating the correct Jacobian is
extremely demanding. The system doesn't converge with an approximate
Jacobian. Is there any SNES solver I should try which doesn't use a
Jacobian?
I haven't tried the FD Jacobian. How do I enable that? I have been
providing the Jacobian.
On Tue, Jun 2, 2015 at 4:59 PM, Matthew Knepley knep...@gmail.com wrote:
On Tue, Jun 2, 2015 at 3:55 PM, Harshad Sahasrabudhe hsaha...@purdue.edu
wrote:
Hi,
Does PETSc have automatic differentiation
On Tue, Jun 2, 2015 at 4:00 PM, Justin Chang jychan...@gmail.com wrote:
MTH did not converge with the default -ksp_rtol 1e-6 so I had to raise the
tolerance to 1e-5 in order to get a solution. Attached are the outputs for
TH and MTH
This really looks like it was never solving this system.
Justin Chang jychan...@gmail.com writes:
Last one with the svd did not work with the way the AMG PC was hard-coded
into FEniCS. Here's the list of preconditioners my installation of FEniCS
supports:
Preconditioner| Description
Eduardo erocha@gmail.com writes:
I am solving a FEM solid mechanics linear elasticity model, for now the
only problem is the mesh that has needle-shaped and very flat elements.
Why does it have such elements? Is the material highly anisotropic
(e.g., fiber)? Is the geometry anisotropic
Hi Jed,
Here is my problem:
I want to evaluate a vector u = B*dw where B and dw are a matrix and a
stochastic vector. However, B = D^(-1/2) in which D is not explicitly
assembled, so it is expensive to directly evaluate B. One solution is to
make a Chebyshev approximation on B w.r.t. D, which
Ozzy,
Thanks for the update. I have changed the checking of the f() as suggested
by the cited reference in master.
Barry
On Jun 1, 2015, at 4:07 AM, Asbjørn Nilsen Riseth ris...@maths.ox.ac.uk
wrote:
Hi again Barry,
I sorted out the jacobian issue, and made a comparison
On Tue, Jun 2, 2015 at 6:13 AM, Justin Chang jychan...@gmail.com wrote:
In FEniCS's Stokes example (example 19), one defines the Taylor-Hood
function spaces with these three lines:
V = VectorFunctionSpace(mesh, CG, 2)
Q = FunctionSpace(mesh, CG, 1)
W = V * Q
To implement P2/(P1+P0), all
Eduardo, as Matt said you problem is ill conditioned but and you might find
that if you add more elements and make the mesh less anisotropic that your
solve faster, and you get a better solution obviously.
I'm not sure what options there are for better discretization but you can
probably do a lot
On Tuesday 02 June 2015 07:43:21 Matthew Knepley wrote:
On Tue, Jun 2, 2015 at 4:52 AM, Francesco Caimmi francesco.cai...@gmail.com
wrote:
with global_vec as v:
for i in xrange(start,end):
v[i] = 5.0*rank
The 'with' construction just uses
VecGetArray()
which
On Tue, Jun 2, 2015 at 9:30 AM, Francesco Caimmi francesco.cai...@polimi.it
wrote:
On Tuesday 02 June 2015 07:43:21 Matthew Knepley wrote:
On Tue, Jun 2, 2015 at 4:52 AM, Francesco Caimmi
francesco.cai...@gmail.com
wrote:
with global_vec as v:
for i in xrange(start,end):
On Mon, Jun 1, 2015 at 9:51 PM, Justin Chang jychan...@gmail.com wrote:
Jed,
I am not quite sure what you're asking for. Are you asking for how people
actually implement this augmented TH? In other words, how the shape/basis
functions for this mixed function space would look? I have only
On Tue, Jun 2, 2015 at 7:18 AM, Lawrence Mitchell
lawrence.mitch...@imperial.ac.uk wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 02/06/15 13:14, Matthew Knepley wrote:
On Tue, Jun 2, 2015 at 6:13 AM, Justin Chang jychan...@gmail.com
mailto:jychan...@gmail.com wrote:
In
On Tue, Jun 2, 2015 at 4:52 AM, Francesco Caimmi francesco.cai...@gmail.com
wrote:
Dear PETSC users,
first of all, many thanks to the developers for making PETSC available.
I am trying to get familiar with the library using petsc4py (my C/C++
knowledge is rudimentary to say the least), and
On Mon, Jun 1, 2015 at 11:24 PM, Eduardo erocha@gmail.com wrote:
I am solving a FEM solid mechanics linear elasticity model, for now the
only problem is the mesh that has needle-shaped and very flat elements.
Have you any suggestion of preconditioner (and references).
The problem here is
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 02/06/15 13:37, Matthew Knepley wrote:
This construction appears to throw away unisolvence.
Yes, it's normally used for building spaces where the resulting
enriched space is unisolvent (e.g. MINI).
In the Boffi paper, they use QR to solve
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
So-called enriched elements in FEniCS are not created with a nodal
basis, instead te basis for the space Q + P is just the
concatenation of the bases for Q and P separately and so tabulation of
basis functions at points is just the
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
So the mass matrix for CG1+DG0 is singular?
I believe so, yes.
Fabulous. Now let's take a one element domain. What is the norm of the
vector
u=((1,1,1),(-1))
in the basis {CG1, DG0}? Note that this represents the continuous
Matthew Knepley knep...@gmail.com writes:
for i in xrange(start,end):
global_vec[i] = 5.0*rank
No, you would need xrange(end-start):
Specifically, Python made a decision about indexing semantics that,
while not irrational, really sucks for distributed array computing. I'm
not aware
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 02/06/15 17:20, Jed Brown wrote:
Lawrence Mitchell lawrence.mitch...@imperial.ac.uk writes:
So the mass matrix for CG1+DG0 is singular?
I believe so, yes.
Fabulous. Now let's take a one element domain. What is the norm
of the vector
Dear all,
I installed PETSC 3.1-p8 library. I am trying compile the fortran code link
to Petsc but there is message saying about target file as follow:
****
*petsc-3.1-p8-openmpi/conf/rules:120: *** target file `clean' has both :
and :: entries. Stop.*
In my makefile I added double-colon to
I made a code to solve the Navier-Stokes equations, incompressible,
non-linear, all coupled, finite differences, staggered grid.
I am running the code with:
-ts_monitor -snes_monitor -ksp_monitor_true_residual -snes_converged_reason
-ksp_converged_reason -pc_type fieldsplit -pc_fieldsplit_type
On Tue, Jun 2, 2015 at 12:17 PM, Tuan Nguyen tuan.v...@gmail.com wrote:
Dear all,
I installed PETSC 3.1-p8 library. I am trying compile the fortran code
link to Petsc but there is message saying about target file as follow:
****
*petsc-3.1-p8-openmpi/conf/rules:120: *** target file
On Tue, Jun 2, 2015 at 12:26 PM, Italo Tasso it...@tasso.com.br wrote:
I made a code to solve the Navier-Stokes equations, incompressible,
non-linear, all coupled, finite differences, staggered grid.
I am running the code with:
-ts_monitor -snes_monitor -ksp_monitor_true_residual
Run for one time-step with -ts_view so we can see exactly what solver
options you are using.
Then run with the additional options -ksp_pc_side right
-ts_max_snes_failures -1
On Jun 2, 2015, at 12:26 PM, Italo Tasso it...@tasso.com.br wrote:
I made a code to solve the
37 matches
Mail list logo
