Sorry, I do not know how the reply went to your id. I replied the usual way.
I am solving : div(grad(V)) = 0 for x in [0, L] and V(0) = V1 and V(L) = V1 I get a solution V(x) = V1 after solving with intial guess V(X) = 0 for x in (0, L) Now, what is the user defined ? is it V(X) = 0 ? or V(x) = V1 ? Is the user defined state is V(X) = V1 then it means the Jacobin is tested after doing a solve first ? But then, for a linear Poisson problem, The Jacobin should be independent of V(X). I seem to get correct solution but snes_type test (fails ?) can you give me some pointers on how to debug this ? Thanks On Wed, Apr 17, 2013 at 5:55 PM, Dharmendar Reddy <dharmareddy84 at gmail.com>wrote: > I am confused. > > I am solving : div(grad(V)) = 0 for x in [0, L] and V(0) = V1 and V(L) > = V1 > > I get a solution V(x) = V1 after solving with intial guess V(X) = 0 for x > in (0, L) > > Now, what is the user defined ? is it V(X) = 0 ? or V(x) = V1 ? > > Is the user defined state is V(X) = V1 then it means the Jacobin is tested > after doing a solve first ? > > But then, for a linear Poisson problem, The Jacobin should be independent > of V(X). I seem to get correct solution but snes_type test (fails ?) can > you give me some pointers on how to debug this ? > > Thanks > Reddy > > > > > On Wed, Apr 17, 2013 at 5:36 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote: > >> Dharmendar Reddy <dharmareddy84 at gmail.com> writes: >> >> > Hello, >> > I am solving a one dimensional (linear) Poisson equation. I >> have >> > setup a snes problem using DM object. I am using Dirichlet boundary >> > conditons at both ends of the one dimensional domain. For the test case >> i >> > use the same value for potential at both ends. >> > >> > I am using DMplex object for the mesh and dof lay out. >> > >> > If i run the solver, i get a constant potential profile as expected. >> > However, If i run the solver with snes_type test >> > It is giving an error. what could i have done wrong ? >> > Testing hand-coded Jacobian, if the ratio is >> > O(1.e-8), the hand-coded Jacobian is probably correct. >> > Run with -snes_test_display to show difference >> > of hand-coded and finite difference Jacobian. >> > Norm of matrix ratio 1.0913e-10 difference 5.85042e-10 (user-defined >> state) >> > Norm of matrix ratio 0.5 difference 5.36098 (constant state -1.0) >> > Norm of matrix ratio 0.666667 difference 10.722 (constant state 1.0) >> > [0]PETSC ERROR: --------------------- Error Message >> > ----------------------------------- >> > - >> > [0]PETSC ERROR: Object is in wrong state! >> > [0]PETSC ERROR: SNESTest aborts after Jacobian test! >> >> This is what '-snes_type test' is supposed to do. So you're fine and >> your Jacobian is fine at the initial state, but not at the constant >> value 1.0 or -1.0. (That's okay if those are non-physical states, >> otherwise your Jacobian evaluation is incorrect.) >> >> > [0]PETSC ERROR: >> > ----------------------------------------------------------------------- >> > - >> > [0]PETSC ERROR: Petsc Development GIT revision: >> > e0030536e6573667cee5340eb367e8213e67d68 >> > 9 GIT Date: 2013-04-16 21:48:15 -0500 >> > [0]PETSC ERROR: See docs/changes/index.html for recent updates. >> > [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting. >> > [0]PETSC ERROR: See docs/index.html for manual pages. >> > [0]PETSC ERROR: >> > ----------------------------------------------------------------------- >> > - >> > [0]PETSC ERROR: ./PoisTest on a mpi_rScalar_Debug named >> > login2.stampede.tacc.utexas.edu >> > by Reddy135 Wed Apr 17 17:22:02 2013 >> > [0]PETSC ERROR: Libraries linked from >> > /home1/00924/Reddy135/LocalApps/petsc/mpi_rScalar >> > _Debug/lib >> > [0]PETSC ERROR: Configure run at Tue Apr 16 22:30:58 2013 >> > [0]PETSC ERROR: Configure options --download-blacs=1 >> --download-ctetgen=1 >> > --download- >> > metis=1 --download-mumps=1 --download-parmetis=1 --download-scalapack=1 >> > --download-supe >> > rlu_dist=1 --download-triangle=1 --download-umfpack=1 >> > --with-blas-lapack-dir=/opt/apps/ >> > intel/13/composer_xe_2013.2.146/mkl/lib/intel64/ --with-debugging=1 >> > --with-mpi-dir=/opt >> > /apps/intel13/mvapich2/1.9/ --with-petsc-arch=mpi_rScalar_Debug >> > --with-petsc-dir=/home1 >> > /00924/Reddy135/LocalApps/petsc PETSC_ARCH=mpi_rScalar_Debug >> > [0]PETSC ERROR: >> > ----------------------------------------------------------------------- >> > - >> > [0]PETSC ERROR: SNESSolve_Test() line 127 in >> > /home1/00924/Reddy135/LocalApps/petsc/src/ >> > snes/impls/test/snestest.c >> > [0]PETSC ERROR: SNESSolve() line 3755 in >> > /home1/00924/Reddy135/LocalApps/petsc/src/snes >> > /interface/snes.c >> > SNESDivergedReason 0 >> > Exiting solve >> > -- >> > ----------------------------------------------------- >> > Dharmendar Reddy Palle >> > Graduate Student >> > Microelectronics Research center, >> > University of Texas at Austin, >> > 10100 Burnet Road, Bldg. 160 >> > MER 2.608F, TX 78758-4445 >> > e-mail: dharmareddy84 at gmail.com >> > Phone: +1-512-350-9082 >> > United States of America. >> > Homepage: https://webspace.utexas.edu/~dpr342 >> > > > > -- > ----------------------------------------------------- > Dharmendar Reddy Palle > Graduate Student > Microelectronics Research center, > University of Texas at Austin, > 10100 Burnet Road, Bldg. 160 > MER 2.608F, TX 78758-4445 > e-mail: dharmareddy84 at gmail.com > Phone: +1-512-350-9082 > United States of America. > Homepage: https://webspace.utexas.edu/~dpr342 > -- ----------------------------------------------------- Dharmendar Reddy Palle Graduate Student Microelectronics Research center, University of Texas at Austin, 10100 Burnet Road, Bldg. 160 MER 2.608F, TX 78758-4445 e-mail: dharmareddy84 at gmail.com Phone: +1-512-350-9082 United States of America. 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