/**
- * 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
* <i>interpolates</i> the given function $f(x)$, i.e.,
* @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.,