const double inner_radius = 0.5, outer_radius = 1.0;
GridGenerator::hyper_shell(
triangulation, center, inner_radius, outer_radius, 10);
- // By default, the triangulation assumes that all boundaries are
- // straight lines, and all cells are bi-linear quads or tri-linear
- // hexes, and that they are defined by the cells of the coarse grid
- // (which we just created). Unless we do something special, when new
- // points need to be introduced the domain is assumed to be
- // delineated by the straight lines of the coarse mesh, and new
- // points will simply be in the middle of the surrounding ones.
- // Here, however, we know that the domain is curved, and we would
- // like to have the Triangulation place new points according to the
- // underlying geometry. Fortunately, some good soul implemented an
- // object which describes a spherical domain, of which the ring is a
- // section; it only needs the center of the ring and automatically
- // figures out how to instruct the Triangulation where to place the
- // new points. The way this works in deal.II is that you tag parts
- // of the triangulation you want to be curved with a number that is
+ // By default, the triangulation assumes that all boundaries are straight
+ // lines, and all cells are bi-linear quads or tri-linear hexes, and that
+ // they are defined by the cells of the coarse grid (which we just
+ // created). Unless we do something special, when new points need to be
+ // introduced the domain is assumed to be delineated by the straight
+ // lines of the coarse mesh, and new points will simply be in the middle
+ // of the surrounding ones. Here, however, we know that the domain is
+ // curved, and we would like to have the Triangulation place new points
+ // according to the underlying geometry. Fortunately, some good soul
+ // implemented an object which describes a spherical domain, of which the
+ // ring is a section; it only needs the center of the ring and
+ // automatically figures out how to instruct the Triangulation where to
+ // place the new points. The way this works in deal.II is that you tag
+ // parts of the triangulation you want to be curved with a number that is
// usually referred to as "manifold indicator" and then tell the
- // triangulation to use a particular "manifold object" for all
- // places with this manifold indicator. How exactly this works is
- // not important at this point (you can read up on it in step-53 and
- // @ref manifold). The functions in GridGenerator handle this for us in most
- // circumstances: they attach the correct manifold to a domain so that when
- // the triangulation is refined new cells are placed in the correct
+ // triangulation to use a particular "manifold object" for all places
+ // with this manifold indicator. How exactly this works is not important
+ // at this point (you can read up on it in step-53 and @ref manifold).
+ // The functions in GridGenerator handle this for us in most
+ // circumstances: they attach the correct manifold to a domain so that
+ // when the triangulation is refined new cells are placed in the correct
// places. In the present case GridGenerator::hyper_shell attaches a
// SphericalManifold to all cells: this causes cells to be refined with
- // calculations in spherical coordinates (so new cells have edges that are
- // either radial or lie along concentric circles around the origin).
+ // calculations in spherical coordinates (so new cells have edges that
+ // are either radial or lie along concentric circles around the origin).
//
- // By default (i.e., for a Triangulation created by hand or without a call
- // to a GridGenerator function like GridGenerator::hyper_shell or
- // GridGenerator::hyper_ball), all cells and
- // faces of the Triangulation have their manifold_id set to
- // numbers::invalid_manifold_id, which is the default if you want a
- // manifold that produces straight edges, but you can change this
- // number for individual cells and faces. In that case, the curved
- // manifold thus associated with number zero will not apply to those
- // parts with a non-zero manifold indicator, but other manifold
- // description objects can be associated with those non-zero
- // indicators. If no manifold description is associated with a
- // particular manifold indicator, a manifold that produces straight
- // edges is implied. (Manifold indicators are a slightly complicated
- // topic; if you're confused about what exactly is happening here,
- // you may want to look at the @ref GlossManifoldIndicator "glossary
- // entry on this topic".) Since the default chosen by
- // GridGenerator::hyper_shell is reasonable we leave things alone.
+ // By default (i.e., for a Triangulation created by hand or without a
+ // call to a GridGenerator function like GridGenerator::hyper_shell or
+ // GridGenerator::hyper_ball), all cells and faces of the Triangulation
+ // have their manifold_id set to numbers::invalid_manifold_id, which is
+ // the default if you want a manifold that produces straight edges, but
+ // you can change this number for individual cells and faces. In that
+ // case, the curved manifold thus associated with number zero will not
+ // apply to those parts with a non-zero manifold indicator, but other
+ // manifold description objects can be associated with those non-zero
+ // indicators. If no manifold description is associated with a particular
+ // manifold indicator, a manifold that produces straight edges is
+ // implied. (Manifold indicators are a slightly complicated topic; if
+ // you're confused about what exactly is happening here, you may want to
+ // look at the @ref GlossManifoldIndicator "glossary entry on this
+ // topic".) Since the default chosen by GridGenerator::hyper_shell is
+ // reasonable we leave things alone.
//
// In order to demonstrate how to write a loop over all cells, we will
// refine the grid in five steps towards the inner circle of the domain:
projects / dealii.git / commitdiff