From: bangerth Date: Mon, 23 Dec 2013 13:23:36 +0000 (+0000) Subject: State that these two elements are discontinuous at places where faces meet. X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4a83eebd7a168c183a8546dbd40ce94336b407e;p=dealii-svn.git State that these two elements are discontinuous at places where faces meet. git-svn-id: https://svn.dealii.org/trunk@32100 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/include/deal.II/fe/fe_face.h b/deal.II/include/deal.II/fe/fe_face.h index 5199cc13c1..af7b702cfa 100644 --- a/deal.II/include/deal.II/fe/fe_face.h +++ b/deal.II/include/deal.II/fe/fe_face.h @@ -33,15 +33,17 @@ DEAL_II_NAMESPACE_OPEN * and two, the polynomials hence correspond to the usual Lagrange polynomials * on equidistant points. * - * This finite element is the trace space of FE_RaviartThomas on the faces and + * Although the name does not give it away, the element is discontinuous + * at locations where faces of cells meet. In particular, + * this finite element is the trace space of FE_RaviartThomas on the faces and * serves in hybridized methods, e.g. in combination with the FE_DGQ * element. Its use is demonstrated in the step-51 tutorial program. * - * @note Since these are only finite elements on faces, only + * @note Since this element is defined only on faces, only * FEFaceValues and FESubfaceValues will be able to extract reasonable * values from any face polynomial. In order to make the use of - * FESystem simpler, FEValues objects will not fail using this finite - * element space, but all shape function values extracted will equal + * FESystem simpler, using a (cell) FEValues object will not fail using this finite + * element space, but all shape function values extracted will be equal * to zero. * * @ingroup fe @@ -133,18 +135,22 @@ private: /** - * A finite element, which is a Legendre on each face (i.e., FE_DGP) + * A finite element, which is a Legendre element of complete polynomials on + * each face (i.e., it is the face equivalent of what FE_DGP is on cells) * and undefined in the interior of the cells. The basis functions on * the faces are from Polynomials::Legendre. * - * This element is used in a hybridized method together with the FE_DGP - * element for the interior degrees of freedom. + * Although the name does not give it away, the element is discontinuous + * at locations where faces of cells meet. The element + * serves in hybridized methods, e.g. in combination with the FE_DGP + * element. An example of hybridizes methods can be found in the + * step-51 tutorial program. * - * @note Since these are only finite elements on faces, only + * @note Since this element is defined only on faces, only * FEFaceValues and FESubfaceValues will be able to extract reasonable * values from any face polynomial. In order to make the use of - * FESystem simpler, FEValues objects will not fail using this finite - * element space, but all shape function values extracted will equal + * FESystem simpler, using a (cell) FEValues object will not fail using this finite + * element space, but all shape function values extracted will be equal * to zero. * * @ingroup fe