lal::generate::rand_projective_arrangements Class Reference

Uniformly random selection of projective arrangements of a rooted tree. More...

#include <rand_projective_arrangements.hpp>

Public Member Functions
	rand_projective_arrangements (const graphs::rooted_tree &rT, const uint64_t seed=0) noexcept
	Constructor with tree.
	rand_projective_arrangements (const rand_projective_arrangements &Gen) noexcept=default
	Default copy constructor.
	rand_projective_arrangements (rand_projective_arrangements &&Gen) noexcept=default
	Default move constructor.
	~rand_projective_arrangements ()=default
	Default destructor.
linear_arrangement	get_arrangement () noexcept
	Make a random projective arrangement of a rooted tree.
linear_arrangement	yield_arrangement () noexcept
	Returns a random projective arrangement.

Private Attributes
const graphs::rooted_tree &	m_rT
	The rooted tree of which we are making projective arrangements uniformly at random.
detail::array< detail::array< node > >	m_rdata
	The random data for all vertices.
std::mt19937	m_gen
	Random number generator.

Detailed Description

Uniformly random selection of projective arrangements of a rooted tree.

This class does not take into account the symmetries between arrangements produced by swapping leaves of the tree connected to the same parent. That is, the arrangements are select from the can be seen as arrangements of labelled trees. Therefore, this class will select u.a.r. one of the \(n!\) arrangements for a star tree of \(n\) vertices.

See Types of arrangements for the definition of projective arrangements.

An example of usage of this class is

// given a rooted tree T
lal::generate::rand_projective_arrgements Gen(T);
for (int i = 0; i < 100; ++i) {
    const lal::linear_arrangement& arr = Gen.get_arrangement();
    // ...
}

Equivalently,

// given a rooted tree T
lal::generate::rand_projective_arrangements Gen(T);
for (int i = 0; i < 100; ++i) {
    const lal::linear_arrangement& arr = Gen.yield_arrangement();
    // ...
}

Constructor & Destructor Documentation

rand_projective_arrangements() [1/3]

lal::generate::rand_projective_arrangements::rand_projective_arrangements ( const graphs::rooted_tree & rT, const uint64_t seed = 0 )

noexcept

Constructor with tree.

Parameters

rT	Input rooted tree
seed	The seed used for the random generator. If the seed is 0 then a random seed is generated and used.

Precondition

The object t must be a rooted tree (see lal::graphs::rooted_tree::is_rooted_tree).

rand_projective_arrangements() [2/3]

lal::generate::rand_projective_arrangements::rand_projective_arrangements ( const rand_projective_arrangements & Gen )

defaultnoexcept

Default copy constructor.

Parameters

Gen	Random projective arrangement generator.

rand_projective_arrangements() [3/3]

lal::generate::rand_projective_arrangements::rand_projective_arrangements ( rand_projective_arrangements && Gen )

defaultnoexcept

Default move constructor.

Parameters

Gen	Random projective arrangement generator.

Member Function Documentation

get_arrangement()

linear_arrangement lal::generate::rand_projective_arrangements::get_arrangement ( )

nodiscardnoexcept

Make a random projective arrangement of a rooted tree.

Returns

A projective arrangement chosen uniformly at random chosen amongst all projective arrangements of t.

Member Data Documentation

m_rdata

detail::array<detail::array<node> > lal::generate::rand_projective_arrangements::m_rdata

private

The random data for all vertices.

This is a member of the class to avoid its initialisation at every call to get_arrangement.

---

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

• lal/generate/rand_projective_arrangements.hpp