tgen::permutation::value

Permutation value. More...

Inheritance diagram for tgen::permutation::value:

Public Member Functions
	value (const std::vector< int > &vec)
	Creates a permutation value from a std::vector.
int	size () const
	Returns the size of the permutation value.
const int &	operator[] (int idx) const
	Returns the image at some position of the permutation.
int	parity () const
	Parity of the permutation.
value &	sort ()
	Sorts the permutation in non-decreasing order.
value &	reverse ()
	Reverses the permutation.
value &	inverse ()
	Inverse of the permutation.
value &	separator (char sep)
	Sets separator for printing.
value &	print_1_based ()
	Sets that printed values are 1-based.
value &	shuffle ()
	Shuffles the permutation.
int	pick () const
	Returns a uniformly random element.
template<typename Dist>
int	pick_by_distribution (const std::vector< Dist > &distribution) const
	Returns a random element from the permutation with given probabilities.
std::vector< int >	to_std () const
	Converts the permutation to a std::vector.
std::vector< int >	to_std_1_based () const
	Converts the permutation to a 1-based std::vector.
Public Member Functions inherited from tgen::gen_value_base< value >
bool	operator< (const value &rhs) const

Friends
std::ostream &	operator<< (std::ostream &out, const value &val)
	Prints the permutation to an output stream.

Detailed Description

Permutation value.

It can be printed through std::cout.

Definition at line 2236 of file tgen.h.

Constructor & Destructor Documentation

value()

tgen::permutation::value::value ( const std::vector< int > & vec )

inline

Creates a permutation value from a std::vector.

Parameters

vec	The std::vector representing the permutation.

Examples

// Creates and prints a permutation from a std::vector.
std::vector<int> v = {0, 1, 2};
tgen::permutation::value val(v);
std::cout << val << std::endl; // Prints "0 1 2".
 
// Also works with conversions, and std::initializer_list<T>.
val = {1, 0};
std::cout << val.print_1_based() << std::endl; // Prints "2 1".

Definition at line 2244 of file tgen.h.

Member Function Documentation

inverse()

value & tgen::permutation::value::inverse ( )

inline

Inverse of the permutation.

The inverse of the permutation p is another pi such that pi[p[i]] = p[pi[i]] = i.

Time complexity

O(n).

Examples

// Prints inverse of permutation.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.inverse() << std::endl; // Prints "1 2 0".

Definition at line 2304 of file tgen.h.

operator[]()

const int & tgen::permutation::value::operator[] ( int idx ) const

inline

Returns the image at some position of the permutation.

Parameters

idx	Index to be accessed.

Returns

The element at index idx.

Examples

// Prints a position of a permutation.
tgen::permutation::value val = {2, 0, 1};
std::cout << val[1] << std::endl; // Prints "0".

Definition at line 2265 of file tgen.h.

parity()

int tgen::permutation::value::parity ( ) const

inline

Parity of the permutation.

Returns

+1 if the permutation is even, or -1 if the permutation is odd.

Examples

// Prints parity of permutation.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.parity() << std::endl; // Prints "1".

Definition at line 2273 of file tgen.h.

pick()

int tgen::permutation::value::pick ( ) const

inline

Returns a uniformly random element.

Returns

A uniformly random element from the permutation.

Time complexity

O(1).

Examples

tgen::permutation::value val = {2, 0, 1};
std::cout << val.pick() << std::endl;

Definition at line 2337 of file tgen.h.

pick_by_distribution()

template<typename Dist>

int tgen::permutation::value::pick_by_distribution ( const std::vector< Dist > & distribution ) const

inline

Returns a random element from the permutation with given probabilities.

Parameters

distribution

Probability distribution.

Returns

A random element from the permutation, chosen with probability proportional to distribution.

Warning

For integral Dist, assumes that the sum of distribution fits in type unsigned __int128.

Time complexity

O(1).

Examples

tgen::permutation::value val = {2, 0, 1};
std::cout << val.pick_by_distribution({1, 2, 3}) << std::endl;

Definition at line 2342 of file tgen.h.

print_1_based()

value & tgen::permutation::value::print_1_based ( )

inline

Sets that printed values are 1-based.

This only affects streaming (std::cout and friends). Stored values, operator[], and to_std() stay 0-based. For a 1-based std::vector, use to_std_1_based().

Time complexity

O(1).

Examples

// Prints a 1-based permutation; to_std() remains 0-based.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.print_1_based() << std::endl; // Prints "3 1 2".
auto zero_based = val.to_std();           // {2, 0, 1}
auto one_based = val.to_std_1_based();    // {3, 1, 2}

Definition at line 2322 of file tgen.h.

reverse()

value & tgen::permutation::value::reverse ( )

inline

Reverses the permutation.

Time complexity

O(n).

Examples

// Reverses and prints a permutation.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.reverse() << std::endl; // Prints "1 0 2".

Definition at line 2297 of file tgen.h.

separator()

value & tgen::permutation::value::separator ( char sep )

inline

Sets separator for printing.

Time complexity

O(1).

Examples

// Prints a permutation, separated by commas.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.separator(',') << std::endl; // Prints "2,0,1".

Definition at line 2314 of file tgen.h.

shuffle()

value & tgen::permutation::value::shuffle ( )

inline

Shuffles the permutation.

Time complexity

O(n).

Examples

tgen::permutation::value val = {2, 0, 1};
std::cout << val.shuffle() << std::endl;

Definition at line 2329 of file tgen.h.

size()

int tgen::permutation::value::size ( ) const

inline

Returns the size of the permutation value.

Returns

The size (number of elements) of the permutation value.

Examples

// Prints the size of a permutation.
tgen::permutation::value val = {0, 1, 2};
std::cout << val.size() << std::endl; // Prints "3".

Definition at line 2262 of file tgen.h.

sort()

value & tgen::permutation::value::sort ( )

inline

Sorts the permutation in non-decreasing order.

Time complexity

O(n).

Examples

// Sorts and prints a permutation.
tgen::permutation::value val = {2, 0, 1};
std::cout << val.sort() << std::endl; // Prints "0 1 2".

Definition at line 2289 of file tgen.h.

to_std()

std::vector< int > tgen::permutation::value::to_std ( ) const

inline

Converts the permutation to a std::vector.

Returns 0-based values. Unaffected by print_1_based(). For a 1-based export, use to_std_1_based().

Returns

A std::vector representing the permutation.

Examples

// Convoluted way to reverse a permutation.
std::vector<int> v = {2, 0, 1};
v = tgen::permutation::value(v).reverse().to_std();
// v = {1, 0, 2}.

Definition at line 2365 of file tgen.h.

to_std_1_based()

std::vector< int > tgen::permutation::value::to_std_1_based ( ) const

inline

Converts the permutation to a 1-based std::vector.

Each element is increased by one. Unaffected by print_1_based().

Returns

A 1-based std::vector representing the permutation.

Examples

auto one_based = tgen::permutation::value({2, 0, 1}).to_std_1_based();
// one_based = {3, 1, 2}.

Definition at line 2369 of file tgen.h.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & out, const value & val )

friend

Prints the permutation to an output stream.

The entries are printed with one space as a separator by default, and with no end of line.

Examples

// Prints a permutation.
std::cout << tgen::permutation::value({2, 0, 1}) << std::endl; // Prints "2 0 1".

Definition at line 2354 of file tgen.h.

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

• /home/runner/work/tgen/tgen/single_include/tgen.h
• permutation.dox