From d54f53aae8fb583ad7193ae4c672b72b9380cee0 Mon Sep 17 00:00:00 2001 From: Martin Kronbichler Date: Tue, 22 Nov 2016 13:30:27 +0100 Subject: [PATCH] Augment description about ghosted vectors --- include/deal.II/matrix_free/matrix_free.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/include/deal.II/matrix_free/matrix_free.h b/include/deal.II/matrix_free/matrix_free.h index 06bd6dccd0..d2e1e9c4a1 100644 --- a/include/deal.II/matrix_free/matrix_free.h +++ b/include/deal.II/matrix_free/matrix_free.h @@ -505,6 +505,16 @@ public: * set accordingly. For vector-valued problems with several DoFHandlers * underlying this class, the parameter @p vector_component defines which * component is to be used. + * + * For the vectors used with MatrixFree and in FEEvaluation, a vector needs + * to hold all @ref GlossLocallyActiveDof "locally active DoFs" and also + * some of the @ref GlossLocallyRelevantDof "locally relevant DoFs". The + * selection of DoFs is such that one can read all degrees of freedom on all + * locally relevant elements (locally active) plus the degrees of freedom + * that contraints expand into from the locally owned cells. However, not + * all locally relevant DoFs are stored because most of them would never be + * accessed in matrix-vector products and result in too much data sent + * around which impacts the performance. */ template void initialize_dof_vector(VectorType &vec, @@ -517,6 +527,16 @@ public: * set accordingly. For vector-valued problems with several DoFHandlers * underlying this class, the parameter @p vector_component defines which * component is to be used. + * + * For the vectors used with MatrixFree and in FEEvaluation, a vector needs + * to hold all @ref GlossLocallyActiveDof "locally active DoFs" and also + * some of the @ref GlossLocallyRelevantDof "locally relevant DoFs". The + * selection of DoFs is such that one can read all degrees of freedom on all + * locally relevant elements (locally active) plus the degrees of freedom + * that contraints expand into from the locally owned cells. However, not + * all locally relevant DoFs are stored because most of them would never be + * accessed in matrix-vector products and result in too much data sent + * around which impacts the performance. */ template void initialize_dof_vector(LinearAlgebra::distributed::Vector &vec, -- 2.39.5