From: Matthias Maier Date: Fri, 15 Sep 2017 15:50:02 +0000 (-0500) Subject: add a note X-Git-Tag: v9.0.0-rc1~1055^2~3 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7595820f1b8afd3eaad060958c0e1d7241bf984;p=dealii.git add a note --- diff --git a/include/deal.II/fe/fe.h b/include/deal.II/fe/fe.h index d9deb79c06..a5a28e3c9c 100644 --- a/include/deal.II/fe/fe.h +++ b/include/deal.II/fe/fe.h @@ -2046,10 +2046,11 @@ public: /** - * Given the values of a function $f(\mathbf x)$ at the (generalized) support - * points, this function then computes what the nodal values of the element - * are, i.e., $\Psi_i[f]$, where $\Psi_i$ are the node functionals of - * the element (see also @ref GlossNodes "Node values or node functionals"). + * Given the values of a function $f(\mathbf x)$ at the (generalized) + * support points of the reference cell, this function then computes what + * the nodal values of the element are, i.e., $\Psi_i[f]$, where $\Psi_i$ + * are the node functionals of the element + * (see also @ref GlossNodes "Node values or node functionals"). * The values $\Psi_i[f]$ are then the expansion coefficients * for the shape functions of the finite element function that * interpolates the given function $f(x)$, i.e., @@ -2106,6 +2107,11 @@ public: * @param[out] nodal_values An array of size @p dofs_per_cell that contains * the node functionals of the element applied to the given function. * + * @note It is safe to call this function for (transformed) values on the + * real cell only for elements with trivial MappingType. For all other + * elements (for example for H(curl), or H(div) conforming elements) + * vector values have to be transformed to the reference cell first. + * * @note Given what the function is supposed to do, the function clearly * can only work for elements that actually implement (generalized) support * points. Elements that do not have generalized support points -- e.g.,