From 0cd69acc465312438c06adcace6186198985c3d4 Mon Sep 17 00:00:00 2001 From: Vachan Potluri Date: Fri, 28 May 2021 11:10:42 +0530 Subject: [PATCH] Add documentation about shape function ordering --- include/deal.II/fe/fe_dgq.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/include/deal.II/fe/fe_dgq.h b/include/deal.II/fe/fe_dgq.h index ca99e86c0e..acf320c6c5 100644 --- a/include/deal.II/fe/fe_dgq.h +++ b/include/deal.II/fe/fe_dgq.h @@ -435,8 +435,14 @@ public: /** * Implementation of scalar, discontinuous tensor product elements based on * Legendre polynomials, described by the tensor product of the polynomial - * space Polynomials::Legendre. As opposed to the basic FE_DGQ element, these - * elements are not interpolatory and no support points are defined. + * space Polynomials::Legendre. The tensor product is achieved using + * TensorProductPolynomials and the ordering of shape functions, like in + * TensorProductPolynomials, is lexicographic. For instance, the ordering in 2d + * is $P_0(x)P_0(y),\ P_1(x)P_0(y),\ \ldots,\ P_n(x)P_0(y),\ P_0(x)P_1(y),\ + * \ldots,\ P_n(x)P_1(y),\ \ldots,\ P_0(x)P_n(y),\ \ldots,\ P_n(x)P_n(y)$ when + * degree=n where $\{P_i\}_{i=0}^{n}$ are the one-dimensional Lagrange + * polynomials defined on $[0,1]$. As opposed to the basic FE_DGQ element, + * these elements are not interpolatory and no support points are defined. * * See the base class documentation in FE_DGQ for details. */ -- 2.39.5