From: Wolfgang Bangerth Date: Wed, 17 Sep 2014 14:42:44 +0000 (-0500) Subject: Allow querying whether a DoF is located on a vertex, line, etc. X-Git-Tag: v8.2.0-rc1~116^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=abc2290e680ef18cfc84b631451cebfcf84886d3;p=dealii.git Allow querying whether a DoF is located on a vertex, line, etc. --- diff --git a/doc/news/changes.h b/doc/news/changes.h index 4b6a158742..0665d082ae 100644 --- a/doc/news/changes.h +++ b/doc/news/changes.h @@ -307,6 +307,13 @@ inconvenience this causes.

Specific improvements

    +
  1. New: The new function FiniteElement::get_associated_geometry_primitive() allows to + query whether a given degree of freedom is associated with a vertex, line, + quad, or hex. +
    + (Wolfgang Bangerth, 2014/09/26) +
    2. +
  2. Fixed: The vector and array versions of Utilities::MPI::sum() and Utilities::MPI::max() produced segmentation faults with some MPI implementations if the input and output arguments were the same. This is now fixed. diff --git a/include/deal.II/base/geometry_info.h b/include/deal.II/base/geometry_info.h index c1eb5547f3..2694688cd6 100644 --- a/include/deal.II/base/geometry_info.h +++ b/include/deal.II/base/geometry_info.h @@ -1,6 +1,6 @@ // --------------------------------------------------------------------- // -// Copyright (C) 1998 - 2013 by the deal.II authors +// Copyright (C) 1998 - 2014 by the deal.II authors // // This file is part of the deal.II library. // @@ -24,6 +24,73 @@ DEAL_II_NAMESPACE_OPEN +/** + * A class that can represent the kinds of objects a triangulation is + * made up of: vertices, lines, quads and hexes. + * + * The class is rather primitive: it only stores a single integer + * that represents the dimensionality of the object represented. + * In other words, this class is useful primarily as a way to + * pass around an object whose data type explains what it does + * (unlike just passing around an integer), and for providing + * symbolic names for these objects such as GeometryPrimitive::vertex + * instead of an integer zero. + * + * Since the ability to identify such objects with the integral + * dimension of the object represented, this class provides + * conversion operators to and from unsigned integers. + * + * @author Wolfgang Bangerth, 2014 + */ +class GeometryPrimitive +{ +public: + /** + * An enumeration providing symbolic names for the + * objects that can be represented by this class. + * The numeric values of these symbolic names equal + * the geometric dimensionality of the represented + * objects to make conversion from and to integer + * variables simpler. + */ + enum Object + { + vertex = 0, + line = 1, + quad = 2, + hex = 3 + }; + + /** + * Constructor. Initialize the object with the + * given argument representing a vertex, line, etc. + */ + GeometryPrimitive (const Object object); + + /** + * Constructor. Initialize the object with an + * integer that should represent the dimensionality of + * the geometric object in question. This will usually be + * a number between zero (a vertex) and three (a hexahedron). + */ + GeometryPrimitive (const unsigned int object_dimension); + + /** + * Return the integral dimension of the object + * currently represented, i.e. zero for a vertex, + * one for a line, etc. + */ + operator unsigned int () const; + +private: + /** + * The object currently represented. + */ + Object object; +}; + + + /** * A class that provides possible choices for isotropic and @@ -2316,6 +2383,30 @@ d_linear_shape_function_gradient (const Point<3> &xi, /* -------------- inline functions ------------- */ + +inline +GeometryPrimitive::GeometryPrimitive (const Object object) + : + object (object) +{} + + + +inline +GeometryPrimitive::GeometryPrimitive (const unsigned int object_dimension) + : + object (static_cast(object_dimension)) +{} + + +inline +GeometryPrimitive::operator unsigned int () const +{ + return static_cast(object); +} + + + namespace internal { diff --git a/include/deal.II/fe/fe.h b/include/deal.II/fe/fe.h index c664461caf..a6e658469f 100644 --- a/include/deal.II/fe/fe.h +++ b/include/deal.II/fe/fe.h @@ -1499,6 +1499,56 @@ public: bool has_generalized_face_support_points () const; + /** + * For a given degree of freedom, return whether it is logically + * associated with a vertex, line, quad or hex. + * + * For instance, for continuous finite elements this coincides with + * the lowest dimensional object the support point of the degree of + * freedom lies on. To give an example, for $Q_1$ elements in 3d, + * every degree of freedom is defined by a shape function that we + * get by interpolating using support points that lie on the + * vertices of the cell. The support of these points of course + * extends to all edges connected to this vertex, as well + * as the adjacent faces and the cell interior, but we say that + * logically the degree of freedom is associated with the vertex as + * this is the lowest-dimensional object it is associated with. + * Likewise, for $Q_2$ elements in 3d, the degrees of freedom + * with support points at edge midpoints would yield a value of + * GeometryPrimitive::line from this function, whereas those on + * the centers of faces in 3d would return GeometryPrimitive::quad. + * + * To make this more formal, the kind of object returned by + * this function represents the object so that the support of the + * shape function corresponding to the degree of freedom, (i.e., that + * part of the domain where the function "lives") is the union + * of all of the cells sharing this object. To return to the example + * above, for $Q_2$ in 3d, the shape function with support point at + * an edge midpoint has support on all cells that share the edge and + * not only the cells that share the adjacent faces, and consequently + * the function will return GeometryPrimitive::line. + * + * On the other hand, for discontinuous elements of type $DGQ_2$, + * a degree of freedom associated with an interpolation polynomial + * that has its support point physically located at a line bounding + * a cell, but is nonzero only on one cell. Consequently, it is + * logically associated with the interior of that cell (i.e., with a + * GeometryPrimitive::quad in 2d and a GeometryPrimitive::hex in 3d). + * + * @param[in] cell_dof_index The index of a shape function or + * degree of freedom. This index must be in the range + * [0,dofs_per_cell). + * + * @note The integer value of the object returned by this function + * equals the dimensionality of the object it describes, and can + * consequently be used in generic programming paradigms. For + * example, if a degree of freedom is associated with a vertex, + * then this function returns GeometryPrimitive::vertex, which has + * a numeric value of zero (the dimensionality of a vertex). + */ + GeometryPrimitive + get_associated_geometry_primitive (const unsigned int cell_dof_index) const; + /** * Interpolate a set of scalar values, computed in the generalized support * points. @@ -2283,6 +2333,28 @@ FiniteElement::is_primitive (const unsigned int i) const +template +inline +GeometryPrimitive +FiniteElement::get_associated_geometry_primitive (const unsigned int cell_dof_index) const +{ + Assert (cell_dof_index < this->dofs_per_cell, + ExcIndexRange (cell_dof_index, 0, this->dofs_per_cell)); + + // just go through the usual cases, taking into account how DoFs + // are enumerated on the reference cell + if (cell_dof_index < this->first_line_index) + return GeometryPrimitive::vertex; + else if (cell_dof_index < this->first_quad_index) + return GeometryPrimitive::line; + else if (cell_dof_index < this->first_hex_index) + return GeometryPrimitive::quad; + else + return GeometryPrimitive::hex; +} + + + DEAL_II_NAMESPACE_CLOSE #endif diff --git a/tests/fe/get_dof_association.cc b/tests/fe/get_dof_association.cc new file mode 100644 index 0000000000..df67185406 --- /dev/null +++ b/tests/fe/get_dof_association.cc @@ -0,0 +1,72 @@ +// --------------------------------------------------------------------- +// $Id$ +// +// Copyright (C) 1998 - 2014 by the deal.II authors +// +// This file is part of the deal.II library. +// +// The deal.II library is free software; you can use it, redistribute +// it, and/or modify it under the terms of the GNU Lesser General +// Public License as published by the Free Software Foundation; either +// version 2.1 of the License, or (at your option) any later version. +// The full text of the license can be found in the file LICENSE at +// the top level of the deal.II distribution. +// +// --------------------------------------------------------------------- + +// test FiniteElement::get_dof_association() with a couple of elements + + +#include "../tests.h" +#include +#include + +#include +#include + + +template +void test (const FiniteElement &fe) +{ + deallog << fe.get_name() << std::endl; + + for (unsigned int i=0; i(2)); + test(FE_Q<2>(2)); + test(FE_Q<3>(2)); + + test(FE_Nedelec<2>(0)); + test(FE_Nedelec<3>(0)); + + test(FE_Nedelec<2>(1)); + test(FE_Nedelec<3>(1)); +} diff --git a/tests/fe/get_dof_association.output b/tests/fe/get_dof_association.output new file mode 100644 index 0000000000..01f8372964 --- /dev/null +++ b/tests/fe/get_dof_association.output @@ -0,0 +1,15 @@ + +DEAL::FE_Q<1>(2) +DEAL::vvl +DEAL::FE_Q<2>(2) +DEAL::vvvvllllq +DEAL::FE_Q<3>(2) +DEAL::vvvvvvvvllllllllllllqqqqqqh +DEAL::FE_Nedelec<2>(0) +DEAL::llll +DEAL::FE_Nedelec<3>(0) +DEAL::llllllllllll +DEAL::FE_Nedelec<2>(1) +DEAL::llllllllqqqq +DEAL::FE_Nedelec<3>(1) +DEAL::llllllllllllllllllllllllqqqqqqqqqqqqqqqqqqqqqqqqhhhhhh