Adapter member types¶
This page contains information about the adapter member types of the FroidurePin
class.
-
using libsemigroups::FroidurePin::Complexity = typename TTraits::Complexity¶
Adapter for the complexity of multiplication.
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 approximate complexity of multiplying two instances of
TElementType
, which may or may not depend on the parameterx
. This is used, for example, by FroidurePin in some member functions to determine whether it is better to multiply elements or to follow a path in the Cayley graph.The second template parameter exists for SFINAE.
- Used by:
- Example
template <> struct Complexity<KBE> { constexpr size_t operator()(KBE const&) const noexcept { return LIMIT_MAX; } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
-
using libsemigroups::FroidurePin::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::FroidurePin::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::FroidurePin::Hash = typename TTraits::Hash¶
Adapter for hashing.
Defined in
adapters.hpp
.This type should be a stateless trivially default constructible with a call operator of signature
size_t operator()(TValueType const&)
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::FroidurePin::IncreaseDegree = typename TTraits::IncreaseDegree¶
Adapter for increasing 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
void operator()(TElementType& x, size_t n) const
(possiblynoexcept
,inline
and/orconstexpr
also).The call operator should change the first argument in-place so that if
m = Degree<TElementType>()(x)
, then after the call toIncreaseDegree<TElementType>()(x, n)
,Degree<TElementType>()(x)
returnsm + n
. This only makes sense for certain types of elements, such as permutations, transformations, or matrices, and not for other types of object. In the latter case, the call operator should simply do nothing. This is used, for example, in the member function FroidurePin::closure, when one of the generators being added has degree larger than the existing generators.The second template parameter exists for SFINAE.
- Used by:
- Example
template <typename TIntegralType> struct IncreaseDegree< TIntegralType, typename std::enable_if<std::is_integral<TIntegralType>::value>::type> { void operator()(TIntegralType&, size_t) const noexcept { } };
- Template Parameters
TElementType – the type of the elements of a semigroup.
-
using libsemigroups::FroidurePin::Less = typename TTraits::Less¶
Adapter for comparisons.
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) which defines a linear order on the objects of type TValueType- Used by:
- Template Parameters
TValueType – the type of objects to compare.
TSfinae – this template parameter can be used for SFINAE.
-
using libsemigroups::FroidurePin::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::FroidurePin::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::FroidurePin::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.