From 47b2634874a50b5b7c95331f6ec627f0413ed108 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Sun, 4 Feb 2018 15:03:36 -0700 Subject: [PATCH] Expand on the explanation of update_quadrature_points. --- include/deal.II/fe/fe_update_flags.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/include/deal.II/fe/fe_update_flags.h b/include/deal.II/fe/fe_update_flags.h index c16d468a17..1e8d77f770 100644 --- a/include/deal.II/fe/fe_update_flags.h +++ b/include/deal.II/fe/fe_update_flags.h @@ -99,7 +99,18 @@ enum UpdateFlags update_boundary_forms = 0x0010, //! Transformed quadrature points /** - * Compute the quadrature points transformed into real cell coordinates. + * Compute the quadrature points location in real cell coordinates. + * + * FEValues objects take the quadrature point locations on the + * reference cell as an argument of the constructor (via the + * Quadrature object). For most finite elements, knowing the + * location of quadrature points on the reference cell is all that + * is necessary to evaluate shape functions, evaluate the mapping, + * and other things. On the other hand, if you want to evaluate a + * right hand side function $f(\mathbf x_q)$ at quadrature point + * locations $\mathbf x_q$ on the real cell, you need to pass this + * flag to the FEValues constructor to make sure you can later + * access them. */ update_quadrature_points = 0x0020, //! Transformed quadrature weights -- 2.39.5