From 2f4773351b711d116fb0c5f614088cb49f31dc06 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Wed, 1 Jul 2009 08:58:30 +0000 Subject: [PATCH] Comment in the call to set_which_eigenpairs. Make sure constrained DoFs have non-zero diagonal entries in the matrix. git-svn-id: https://svn.dealii.org/trunk@19010 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/examples/step-36/step-36.cc | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/deal.II/examples/step-36/step-36.cc b/deal.II/examples/step-36/step-36.cc index 347b9931e9..008ee2bb21 100644 --- a/deal.II/examples/step-36/step-36.cc +++ b/deal.II/examples/step-36/step-36.cc @@ -215,6 +215,20 @@ void EigenvalueProblem::assemble_system () // vectors in an assembled state. stiffness_matrix.compress(); mass_matrix.compress(); + + // make sure that the diagonal entries of + // constrained degrees of freedom are + // non-zero to ensure that the matrix is + // actually invertible + for (unsigned int i=0; i::solve () // choose which part of the spectrum to // solve for - // eigensolver.set_which_eigenpairs (); + eigensolver.set_which_eigenpairs (EPS_SMALLEST_MAGNITUDE); // then actually solve the system, -- 2.39.5