WtShortLexCompare

Defined in order.hpp.

A stateful struct with binary call operator using wt_shortlex_compare or wt_shortlex_compare_no_checks, depending on the value of the constructor parameter should_check. This struct stores a copy of a weights vector and can be used as a template parameter for standard library containers or algorithms that require a comparison functor.

Warning

When the constructor parameter should_check is false, the call operator does not check that letters are valid indices into the weights vector. Use the constructor with should_check set to true (checks) to enable argument checking in the call operator.

See also

• wt_shortlex_compare(Thing const&, Thing const&, std::vector<size_t> const&)
• wt_shortlex_compare_no_checks(Thing const&, Thing const&, std::vector<size_t> const&)

Static Public Attributes
static constexpr bool	checks = true
	Constant to enable validity checks.
static constexpr bool	no_checks = false
	Constant to disable validity checks.

Public Member Functions
	WtShortLexCompare (std::vector< size_t > &&weights, bool should_check)
	Construct from weights vector rvalue reference and specify whether or not the call operator should check its arguments.
	WtShortLexCompare (std::vector< size_t > const &weights, bool should_check)
	Construct from weights vector reference and specify whether or not the call operator should check its arguments.
template<typename Thing>
bool	call_no_checks (Thing const &x, Thing const &y) const
	Call operator that does no checks.
WtShortLexCompare &	init (std::vector< size_t > &&weights, bool should_check)
	Reinitialize an existing WtShortLexCompare object.
WtShortLexCompare &	init (std::vector< size_t > const &weights, bool should_check)
	Reinitialize an existing WtShortLexCompare object.
template<typename Thing>
bool	operator() (Thing const &x, Thing const &y) const
	Call operator that compares x and y using either wt_shortlex_compare or wt_shortlex_compare_no_checks.
bool	should_check () const noexcept
	Returns the value of the constructor parameter should_check.
WtShortLexCompare &	should_check (bool val) noexcept
	Set the value of the constructor parameter should_check.
std::vector< size_t > const &	weights () const noexcept
	Returns the weights.
WtShortLexCompare &	weights (std::vector< size_t > const &val)
	Set the weights.

Constructor & Destructor Documentation

WtShortLexCompare() [1/2]

WtShortLexCompare ( std::vector< size_t > const & weights, bool should_check )

inline

Constructs a comparison object that stores a copy of the provided weights vector, where the ith index corresponds to the weight of the ith letter in the alphabet. The should_check parameter determines whether the call operator will validate that letters are valid indices.

Parameters

weights	the weights vector.
should_check	if true (checks), the call operator will check validity; if false (no_checks), it will not.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

WtShortLexCompare() [2/2]

WtShortLexCompare ( std::vector< size_t > && weights, bool should_check )

inline

Constructs a comparison object that takes ownership of the provided weights vector, where the ith index corresponds to the weight of the ith letter in the alphabet. The should_check parameter determines whether the call operator will validate that letters are valid indices.

Parameters

weights	the weights vector.
should_check	if true (checks), the call operator will check validity; if false (no_checks), it will not.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

Member Function Documentation

call_no_checks()

template<typename Thing>

bool call_no_checks ( Thing const & x, Thing const & y ) const

inlinenodiscard

This member function always uses wt_shortlex_compare_no_checks to compare x and y, regardless of the value of the constructor parameter should_check. Use this when you want to ensure validation is not performed.

Template Parameters

Thing

the type of the objects to be compared.

Parameters

x	const reference to the first object for comparison.
y	const reference to the second object for comparison.

Returns

The boolean value true if x is weighted short-lex less than y, and false otherwise.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

Complexity

See wt_shortlex_compare_no_checks(Iterator, Iterator, Iterator, Iterator, std::vector<size_t> const&)

init() [1/2]

WtShortLexCompare & init ( std::vector< size_t > && weights, bool should_check )

inline

This function reinitializes an existing WtShortLexCompare object so that it is in the same state as if it was newly constructed using the same arguments.

Parameters

weights	the weights vector.
should_check	if true (checks), the call operator will check validity; if false (no_checks), it will not.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

init() [2/2]

WtShortLexCompare & init ( std::vector< size_t > const & weights, bool should_check )

inline

This function reinitializes an existing WtShortLexCompare object so that it is in the same state as if it was newly constructed using the same arguments.

Parameters

weights	the weights vector.
should_check	if true (checks), the call operator will check validity; if false (no_checks), it will not.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

operator()()

template<typename Thing>

bool operator() ( Thing const & x, Thing const & y ) const

inlinenodiscard

Call operator that compares x and y using wt_shortlex_compare (if the constructor parameter should_check is true) or wt_shortlex_compare_no_checks (if should_check is false).

Template Parameters

Thing

the type of the objects to be compared.

Parameters

x	const reference to the first object for comparison.
y	const reference to the second object for comparison.

Returns

The boolean value true if x is weighted short-lex less than y, and false otherwise.

Exceptions

LibsemigroupsException

if the constructor parameter should_check is true and any letter is not a valid index into the weights vector.

Complexity

See

• wt_shortlex_compare(Iterator, Iterator, Iterator, Iterator, std::vector<size_t> const&);
• wt_shortlex_compare_no_checks(Iterator, Iterator, Iterator, Iterator, std::vector<size_t> const&).

Warning

If the constructor parameter should_check is false, it is not checked that the letters are valid indices into the weights vector.

should_check() [1/2]

bool should_check ( ) const

inlinenodiscardnoexcept

This function returns the current value of the constructor parameter should_check.

Returns

Whether or not the call operator is checking its arguments.

Exceptions

This function is noexcept and is guaranteed never to throw.

See also

should_check(bool)

should_check() [2/2]

WtShortLexCompare & should_check ( bool val )

inlinenoexcept

This function sets the value of should_check to val. This parameter determines whether or not the call operator is checking its arguments.

Parameters

val	the new value of should_check.

Returns

A reference to *this.

Exceptions

This function is noexcept and is guaranteed never to throw.

See also

should_check()

weights() [1/2]

std::vector< size_t > const & weights ( ) const

inlinenodiscardnoexcept

This function returns the current value of the weights used to define the comparison implemented by WtShortLexCompare.

Returns

The current weights.

Exceptions

This function is noexcept and is guaranteed never to throw.

weights() [2/2]

WtShortLexCompare & weights ( std::vector< size_t > const & val )

inline

This function can be used to redefine the weights used to define the comparison implemented by WtShortLexCompare.

Parameters

val	the new weights to use.

Returns

A reference to *this.

Exceptions

This function is noexcept and is guaranteed never to throw.

Member Data Documentation

checks

bool checks = true

staticconstexpr

This constant can be used in the constructors to indicate that checks should be performed on the arguments to the call operator.

no_checks

bool no_checks = false

staticconstexpr

This constant can be used in the constructors to indicate that no checks should be performed on the arguments to the call operator.

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The documentation for this struct was generated from the following file:

• /Users/jdm3/libsemigroups/include/libsemigroups/order.hpp