Adapter types¶
This page contains the documentation for adapters for the SchreierSims
class.
-
using libsemigroups::SchreierSims::Action = typename TTraits::Action¶
Alias for
TTraits::Action
.See Action for further details.
-
using libsemigroups::SchreierSims::Degree = typename TTraits::Degree¶
Adapter for the degree of an element.
Defined in
adapters.hpp
.Specialisations of this struct should be stateless trivially default constructible with a call operator of signature
size_t operator()(TElementType const& x) const
(possiblynoexcept
,inline
and/orconstexpr
also).The return value of the call operator ought to indicate the degree of a
TElementType
instance which may or may not depend on the parameterx
. The degree of a permutation, for instance, would be the the number of points it acts on, the degree of a matrix is its dimension, and so on. This is used, for example, by SchreierSimsTraits in some member functions to determine whether it is known a priori that a permutation does not belong to the object, because it acts on too many points.- Used by:
- Example
template <> struct Degree<BMat8> { constexpr inline size_t operator()(BMat8 const&) const noexcept { return 8; } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
TSfinae – this template parameter can be used for SFINAE.
-
using libsemigroups::SchreierSims::EqualTo = typename TTraits::EqualTo¶
Adapter for testing equality.
Defined in
adapters.hpp
.This type should be a stateless trivially default constructible with a call operator of signature
bool operator()(TValueType const&, TValueType const&)
(possiblynoexcept
,inline
and/orconstexpr
also) for use with, for example, std::unordered_map.- Template Parameters
TValueType – the type of objects to compare.
TSfinae – this template parameter can be used for SFINAE.
-
using libsemigroups::SchreierSims::Inverse = typename TTraits::Inverse¶
Adapter for the inverse of an element.
Defined in
adapters.hpp
.Specialisations of this struct should be stateless trivially default constructible with a call operator of signature
TPointType operator()(TElementType const& x) const
(possiblynoexcept
,inline
and/orconstexpr
also).The call operator should return the inverse of the element
x
under the assumption thatx
has an inverse (in the sense of groups). For example, ifx
is a permutation, then this would return its inverse. Ifx
is a permutation matrix of type BMat8, then this operator would return its transpose.The second template parameter exists for SFINAE.
- Used by:
- Example
template <> struct Inverse<BMat8> { inline BMat8 operator()(BMat8 const& x) const noexcept { LIBSEMIGROUPS_ASSERT(x * x.transpose() == x.one()); return x.transpose(); } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
-
using libsemigroups::SchreierSims::One = typename TTraits::One¶
Adapter for the identity element of the given type.
Specialisations of this struct should be stateless trivially default constructible with two call operator of signatures:
TElementType operator()(size_t n) const
(possiblynoexcept
,inline
and/orconstexpr
also) returning a multiplicative identity element for the categoryTElementType
and withDegree<TElementType>()(x)
equal to the parametern
. For example, ifTElementType
is a type of n x n matrices, then this should return the n x n identity matrix.TElementType operator()(T const&) const
(possiblynoexcept
,inline
and/orconstexpr
also). This could be implemented as:TElementType operator()(TElementType const& x) const noexcept { return this->operator()(Degree<TElementType>()(x)); }
- Used by:
- Example
template <typename T> struct One< T, typename std::enable_if<std::is_base_of<PTransf16, T>::value>::type> { T operator()(size_t = 0) const noexcept { return T::one(); } T operator()(T const&) const noexcept { return T::one(); } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
TSfinae – this template parameter can be used for SFINAE.
-
using libsemigroups::SchreierSims::Product = typename TTraits::Product¶
Adapter for the product of two elements.
Defined in
adapters.hpp
.Specialisations of this struct should be stateless trivially default constructible with a call operator of signature
void operator()(TElementType& xy, TElementType const& x, TElementType const& y, size_t = 0)
(possiblynoexcept
,inline
and/orconstexpr
also).The call operator should change
xy
in-place to be the product ofx
andy
. The 4th parameter is optional and it can be used as an index for static thread local storage, that might be required for forming the product ofx
andy
. The purpose of the 1st parameter is to avoid repeated allocations of memory to hold temporary products that are discarded soon after they are created.- Used by:
- Example
template <> struct Product<size_t> { void operator()(size_t& xy, size_t x, size_t y, size_t = 0) const noexcept { xy = x * y; } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
TSfinae – this template parameter can be used for SFINAE.
-
using libsemigroups::SchreierSims::Swap = typename TTraits::Swap¶
Adapter for swapping.
Defined in
adapters.hpp
.This type should be a stateless trivially default constructible with a call operator of signature
void operator()(TValueType const&, TValueType const&)
(possiblynoexcept
,inline
and/orconstexpr
also) which swaps its arguments.- Template Parameters
TValueType – the type of objects to compare.
TSfinae – this template parameter can be used for SFINAE.