From: Wolfgang Bangerth Date: Mon, 18 Nov 2019 17:32:16 +0000 (-0700) Subject: Clarify documentation. X-Git-Tag: v9.2.0-rc1~870^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=942b43dcabc4335f48e3f820e4b68cd0ec465df2;p=dealii.git Clarify documentation. --- diff --git a/include/deal.II/fe/fe_values.h b/include/deal.II/fe/fe_values.h index da9b132a57..2b0e292ced 100644 --- a/include/deal.II/fe/fe_values.h +++ b/include/deal.II/fe/fe_values.h @@ -3113,10 +3113,16 @@ public: get_inverse_jacobians() const; /** - * For a face, return the outward normal vector to the cell at the - * ith quadrature point. - * - * For a cell of codimension one, return the normal vector. There are of + * Return the normal vector at a quadrature point. If you call this + * function for a face (i.e., when using a FEFaceValues or FESubfaceValues + * object), then this function returns the outward normal vector to + * the cell at the ith quadrature point of the face. + * + * In contrast, if you call this function for a cell of codimension one + * (i.e., when using a `FEValues` object with + * `spacedim>dim`), then this function returns the normal vector to the + * cell -- in other words, an approximation to the normal vector to the + * manifold in which the triangulation is embedded. There are of * course two normal directions to a manifold in that case, and this * function returns the "up" direction as induced by the numbering of the * vertices. @@ -3129,9 +3135,9 @@ public: normal_vector(const unsigned int i) const; /** - * Return the normal vectors at the quadrature points. For a face, these are - * the outward normal vectors to the cell. For a cell of codimension one, - * the orientation is given by the numbering of vertices. + * Return the normal vectors at all quadrature points represented by + * this object. See the normal_vector() function for what the normal + * vectors represent. * * @dealiiRequiresUpdateFlags{update_normal_vectors} * @@ -3143,9 +3149,9 @@ public: get_all_normal_vectors() const; /** - * Return the normal vectors at the quadrature points. For a face, these are - * the outward normal vectors to the cell. For a cell of codimension one, - * the orientation is given by the numbering of vertices. + * Return the normal vectors at all quadrature points represented by + * this object. See the normal_vector() function for what the normal + * vectors represent. * * @dealiiRequiresUpdateFlags{update_normal_vectors} */