From cd4ec352e926ae766dfd2d405d80093c05124fc3 Mon Sep 17 00:00:00 2001 From: bangerth Date: Thu, 28 Oct 2010 23:53:11 +0000 Subject: [PATCH] Update documentation to mention a corner case that Seba found. git-svn-id: https://svn.dealii.org/trunk@22544 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/include/deal.II/numerics/data_out.h | 55 +++++++++++++-------- 1 file changed, 34 insertions(+), 21 deletions(-) diff --git a/deal.II/include/deal.II/numerics/data_out.h b/deal.II/include/deal.II/numerics/data_out.h index c0e627abbd..0cd4978a32 100644 --- a/deal.II/include/deal.II/numerics/data_out.h +++ b/deal.II/include/deal.II/numerics/data_out.h @@ -122,7 +122,7 @@ namespace internal const dealii::hp::QCollection q_collection; const dealii::hp::MappingCollection mapping_collection; dealii::hp::FEValues x_fe_values; - + std::vector > patch_evaluation_points; const std::vector > *cell_to_patch_index_map; @@ -377,26 +377,39 @@ class DataOut_DoFData : public DataOutInterface * and of cells is usually not * equal, the function can * determine itself which type of - * vector it is given; however, - * there is one corner case, - * namely if you compute with - * piecewise constant elements - * and have one scalar quantity, - * then there are as many cells - * as there are degrees of - * freedom, but they may be - * ordered differently. In that - * case, you can change the last - * argument of the function from - * its default value - * #type_automatic to either - * #type_dof_data or #type_cell_data, - * depending on what the vector - * represents. Apart from this - * corner case, you can leave the - * argument at its default value - * and let the function determine - * the type of the vector itself. + * vector it is given. However, + * there are corner cases where + * this automatic determination + * does not work. One example is + * if you compute with piecewise + * constant elements and have a + * scalar solution, then there + * are as many cells as there are + * degrees of freedom (though + * they may be numbered + * differently). Another + * possibility is if you have a + * 1d mesh embedded in 2d space + * and the mesh consists of a + * closed curve of cells; in this + * case, there are as many nodes + * as there are cells, and when + * using a Q1 element you will + * have as many degrees of + * freedom as there are cells. + * In these cases, you can change + * the last argument of the + * function from its default + * value #type_automatic to + * either #type_dof_data or + * #type_cell_data, depending on + * what the vector + * represents. Apart from such + * corner cases, you can leave + * the argument at its default + * value and let the function + * determine the type of the + * vector itself. * * If it is a vector holding DoF * data, the names given shall be -- 2.39.5