From 832efe56cecc3c2bce73b0eb18c74f305338f449 Mon Sep 17 00:00:00 2001 From: guido Date: Wed, 17 Jul 2002 07:48:56 +0000 Subject: [PATCH] Doc updated git-svn-id: https://svn.dealii.org/trunk@6248 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/deal.II/include/fe/fe.h | 75 +++++++++++++++++++++------------ 1 file changed, 49 insertions(+), 26 deletions(-) diff --git a/deal.II/deal.II/include/fe/fe.h b/deal.II/deal.II/include/fe/fe.h index 467bb0e713..98b2a7a8fa 100644 --- a/deal.II/deal.II/include/fe/fe.h +++ b/deal.II/deal.II/include/fe/fe.h @@ -152,37 +152,60 @@ class FiniteElement : public FiniteElementBase protected: /** - * Given a set of flags indicating - * what quantities are requested - * from a @p{FEValues} object, - * return which of these can be - * precomputed once and for - * all. Often, the values of - * shape function at quadrature - * points can be precomputed, for - * example, in which case the - * return value of this function - * would be the logical and of - * the input @p{flags} and - * @p{update_values}. + * Determine the values a finite + * element should compute on + * initialization of data for + * @p{FEValues}. + * + * Given a set of flags + * indicating what quantities are + * requested from a @p{FEValues} + * object, @p{update_once} and + * @p{update_each} compute which + * values must really be + * computed. Then, the + * @p{fill_*_values} functions + * are called with the result of + * these. + * + * Furthermore, values must be + * computed either on the unit + * cell or on the physical + * cell. For instance, the + * function values of @p{FE_Q} do + * only depend on the quadrature + * points on the unit + * cell. Therefore, this flags + * will be returned by + * @p{update_once}. The gradients + * require computation of the + * covariant transformation + * matrix. Therefore, + * @p{update_covariant_transformation} + * and @p{update_gradients} will + * be returned by + * @p{update_each}. + * + * For an example see the same + * function in the derived class + * @p{FE_Q}. */ virtual UpdateFlags update_once (const UpdateFlags flags) const = 0; /** - * This is the opposite to the - * above function: given a set of - * flags indicating what we want - * to know, return which of these - * need to be computed each time - * we visit a new cell. + * Complementary function for + * @p{update_once}. + * + * While @p{update_once} returns + * the values to be computed on + * the unit cell for yielding the + * required data, this function + * determines the values that + * must be recomputed on each + * cell. * - * If for the computation of one - * quantity something else is - * also required (for example, we - * often need the covariant - * transformation when gradients - * need to be computed), include - * this in the result as well. + * Refer to @p{update_once} for + * more details. */ virtual UpdateFlags update_each (const UpdateFlags flags) const = 0; -- 2.39.5