[Libmesh-users] Question about constraining dofs

[Manav B. <bha...@gm...>]

Hi, 

    I am using DofMap::add_constrain_row() to constrain some dofs to zero: 

               libMesh::DofConstraintRow c_row;
            dof_map.add_constraint_row(*dof_it, c_row, true);

    This is implemented in an object derived from System::Constrain. Then, I call System::reinit_constraints() before assembly. 

    This has been working fine, but I have one case that is tripping the following error when I call SparseMatrix::add_matrix(). I am going to start to dig into this to figure out why this might be happening, but if there are any quick words of advice, that would be very helpful. 

    I am a bit puzzled since this is for a diagonal entry. My understanding is that constraining dofs should not remove them from the sparsity pattern. I guess I am missing something here. 

Regards,
Manav   


[1;31m[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0;39m[0;49m[0]PETSC ERROR: Argument out of range
[0]PETSC ERROR: New nonzero at (7308,7308) caused a malloc
Use MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE) to turn off this check
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.8.0, unknown 
[0]PETSC ERROR: /Users/manav/Library/Developer/Xcode/DerivedData/mast_workspace-hfyswujevmwgyugsmyueuaouvmkj/Build/Products/Debug/example_driver on a arch-darwin-c-opt named Dhcp-90-164.HPC.MsState.Edu by manav Thu Mar  1 10:42:54 2018
[0]PETSC ERROR: Configure options --prefix=/Users/manav/Documents/codes/numerical_lib/petsc/petsc/../ --CC=mpicc-openmpi-clang40 --CXX=mpicxx-openmpi-clang40 --FC=mpif90-openmpi-clang40 --with-fortran=0 --with-mpiexec=/opt/local/bin/mpiexec-openmpi-clang40 --with-shared-libraries=1 --with-x=1 --with-x-dir=/opt/X11 --with-debugging=0 --with-lapack-lib=/usr/lib/liblapack.dylib --with-blas-lib=/usr/lib/libblas.dylib --download-superlu=yes --download-superlu_dist=yes --download-suitesparse=yes --download-mumps=yes --download-scalapack=yes --download-parmetis=yes --download-metis=yes --download-hypre=yes --download-ml=yes
[0]PETSC ERROR: #1 MatSetValues_SeqAIJ() line 481 in /Users/manav/Documents/codes/numerical_lib/petsc/petsc/src/mat/impls/aij/seq/aij.c
[0]PETSC ERROR: #2 MatSetValues() line 1270 in /Users/manav/Documents/codes/numerical_lib/petsc/petsc/src/mat/interface/matrix.c