Dune Core Modules (2.8.0)

typeindex.hh
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1// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2// vi: set et ts=4 sw=2 sts=2:
3#ifndef DUNE_GEOMETRY_TYPEINDEX_HH
4#define DUNE_GEOMETRY_TYPEINDEX_HH
5
12#include <cstddef>
13
14#include <dune/common/indices.hh>
15#include <dune/common/hybridutilities.hh>
16
17#include "type.hh"
18
19namespace Dune
20{
23 {
30 inline static constexpr std::size_t regular_size(std::size_t dim)
31 {
32 // The following expression is derived from the expression for
33 // GlobalGeometryTypeIndex::regular_offset(). Subtracting
34 // regular_offset(dim+1)-regular_offset(dim) we get:
35 //
36 // ((1 << dim+1) >> 1) - ((1 << dim) >> 1)
37 //
38 // We always have
39 //
40 // dim >= 0,
41 //
42 // so
43 //
44 // (1 << dim+1) >= 2 and (1 << dim+2) % 2 == 0.
45 //
46 // So if we apply a single right-shift to that, we will never lose any
47 // set bits, thus
48 //
49 // ((1 << dim+1) >> 1) == (1 << dim)
50 return (1 << dim) - ((1 << dim) >> 1);
51 }
52
53 public:
59 inline static constexpr std::size_t size(std::size_t dim)
60 {
61 // one for "none"
62 return regular_size(dim) + 1;
63 }
64
71 inline static constexpr std::size_t index(const GeometryType &gt)
72 {
73 return gt.isNone() ? regular_size(gt.dim()) : (gt.id() >> 1);
74 }
75
77 inline static constexpr GeometryType type(std::size_t dim, std::size_t index) {
78 return (index == regular_size(dim)) ?
80 // the cast to unsigned makes sure this is interpreted as the topology
81 // ID constructor
82 GeometryType(static_cast< unsigned int >(index << 1), dim);
83 }
84 };
85
88 {
96 inline static constexpr std::size_t regular_offset(std::size_t dim)
97 {
98 // The number of regular geometry types in a given dimension is
99 // 2^(dim-1). For dim==0 this would yield 1/2 geometry types (which is
100 // obviously bogus, dim==0 has one regular geometry type, the point).
101 // The following expression relies on 1 >> 1 == 0 to treat dim==0
102 // specially.
103 return (1 << dim) >> 1;
104 }
105
106 public:
111 inline static constexpr std::size_t offset(std::size_t dim)
112 {
113 // dim times "none"
114 return regular_offset(dim) + dim;
115 }
116
123 inline static constexpr std::size_t size(std::size_t maxdim)
124 {
125 return offset(maxdim+1);
126 }
127
136 inline static constexpr std::size_t index(const GeometryType &gt)
137 {
138 return offset(gt.dim()) + LocalGeometryTypeIndex::index(gt);
139 }
140 };
141
142 namespace Impl {
143
144 // Map a dynamic GeometryType to a static integral_constant<GeometryType::Id, ...>
145 template<int dim, class F>
146 static auto toGeometryTypeIdConstant(const GeometryType& gt, F&& f) {
147 // Transform LocalGeometryTypeIndex to GeometryType::Id
148 auto callWithId = [&](auto index) {
149 static constexpr auto id = LocalGeometryTypeIndex::type(dim, decltype(index)::value).toId();
150 return f(std::integral_constant<GeometryType::Id, id>{});
151 };
152 // switchCases needs a fallback to determine the return type.
153 auto fallBack = [&]() { return callWithId(Dune::Indices::_0); };
154 // Iterate over all _regular_ GeometryType indices for given dimension
155 auto allIndices = std::make_index_sequence<LocalGeometryTypeIndex::size(dim)-1>{};
156 return Dune::Hybrid::switchCases(allIndices, LocalGeometryTypeIndex::index(gt), callWithId, fallBack);
157 }
158
159 } // namespace Impl
160} // namespace Dune
161
162#endif // DUNE_GEOMETRY_TYPEINDEX_HH
Unique label for each type of entities that can occur in DUNE grids.
Definition: type.hh:123
constexpr Id toId() const
Create an Id representation of this GeometryType.
Definition: type.hh:219
Compute indices for geometry types, taking the dimension into account.
Definition: typeindex.hh:88
static constexpr std::size_t index(const GeometryType &gt)
Compute the index for the given geometry type over all dimensions.
Definition: typeindex.hh:136
static constexpr std::size_t offset(std::size_t dim)
Compute the starting index for a given dimension including irregular geometry types.
Definition: typeindex.hh:111
static constexpr std::size_t size(std::size_t maxdim)
Compute total number of geometry types up to and including the given dimension.
Definition: typeindex.hh:123
Compute per-dimension indices for geometry types.
Definition: typeindex.hh:23
static constexpr std::size_t size(std::size_t dim)
Compute total number of geometry types for the given dimension.
Definition: typeindex.hh:59
static constexpr GeometryType type(std::size_t dim, std::size_t index)
compute the geometry type for the given local index and dimension
Definition: typeindex.hh:77
static constexpr std::size_t index(const GeometryType &gt)
Compute the index for the given geometry type within its dimension.
Definition: typeindex.hh:71
constexpr index_constant< 0 > _0
Compile time index with value 0.
Definition: indices.hh:51
bool gt(const T &first, const T &second, typename EpsilonType< T >::Type epsilon)
test if first greater than second
Definition: float_cmp.cc:156
constexpr GeometryType none(unsigned int dim)
Returns a GeometryType representing a singular of dimension dim.
Definition: type.hh:479
constexpr decltype(auto) switchCases(const Cases &cases, const Value &value, Branches &&branches, ElseBranch &&elseBranch)
Switch statement.
Definition: hybridutilities.hh:459
Dune namespace.
Definition: alignedallocator.hh:11
A unique label for each type of element that can occur in a grid.
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