Hi Roy, after constraining the matrices I get the correct eigenvalues and wavefunctions -- thank you for helping me solve the problem.
There is one last thing I wanted to ask. When I run the code now (with the constrains), despite obtaining the correct results I get the following error message: [0]PETSC ERROR: --------------------- Error Message ------------------------------------ [0]PETSC ERROR: Detected zero pivot in LU factorization: see http://www.mcs.anl.gov/petsc/documentation/faq.html#ZeroPivot! [0]PETSC ERROR: Empty row in matrix: row in original ordering 1223 in permuted ordering 20! [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: Petsc Release Version 3.3.0, Patch 3, Wed Aug 29 11:26:24 CDT 2012 [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: ./femvib on a arch-linu named peter-VirtualBox by peter Thu Jan 24 09:25:57 2013 [0]PETSC ERROR: Libraries linked from /home/peter/petsc-3.3-p3/arch-linux2-c-debug/lib [0]PETSC ERROR: Configure run at Fri Nov 23 19:14:06 2012 [0]PETSC ERROR: Configure options --download-f2cblaslapack=1 [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: MatLUFactorSymbolic_SeqAIJ() line 334 in src/mat/impls/aij/seq/aijfact.c [0]PETSC ERROR: MatLUFactorSymbolic() line 2750 in src/mat/interface/matrix.c [0]PETSC ERROR: PCSetUp_LU() line 135 in src/ksp/pc/impls/factor/lu/lu.c [0]PETSC ERROR: PCSetUp() line 832 in src/ksp/pc/interface/precon.c [0]PETSC ERROR: KSPSetUp() line 278 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: PCSetUp_Redundant() line 176 in src/ksp/pc/impls/redundant/redundant.c [0]PETSC ERROR: PCSetUp() line 832 in src/ksp/pc/interface/precon.c [0]PETSC ERROR: KSPSetUp() line 278 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: STSetUp_Shift() line 94 in src/st/impls/shift/shift.c [0]PETSC ERROR: STSetUp() line 280 in src/st/interface/stsolve.c [0]PETSC ERROR: EPSSetUp() line 204 in src/eps/interface/setup.c [0]PETSC ERROR: EPSSolve() line 109 in src/eps/interface/solve.c [0]PETSC ERROR: SlepcAbs() line 486 in "unknowndirectory/"src/solvers/slepc_eigen_solver.C application called MPI_Abort(comm=0x84000000, 71) - process 0 According to the PETSC documentation zero pivot does not always mean the matrix is singular and since I am getting the correct results I am ignoring the error. Could my ignorance in this case cause a serious problem in the future I should be aware of? thank you again best Peter Zajac Computational Science Research Center San Diego On Wed, Jan 23, 2013 at 11:33 AM, Roy Stogner <[email protected]>wrote: > > On Wed, 23 Jan 2013, Peter Zajac wrote: > > I am not applying the constraint matrices inside the assemble_mass() >> function. How exactly should I do that? >> > > See the constrain_element_* calls in the example codes. They're > usually important in the context of hanging node constraints, but the > periodic boundary constraints work the same way. (and any > DirichletBoundaries work nearly the same way, if you're currently > using penalty Dirichlet BCs and want to switch) > --- > Roy > ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
