Reproducibility

Typedefs
using	Gudhi::random::Random_generator = std::mt19937_64

Functions
GUDHI_RANDOM_DLL_API Random_generator &	Gudhi::random::get_default_random ()
	Returns a thread-local default random number generator instance.
void	Gudhi::random::set_seed (Random_generator::result_type seed)
	Sets the seed for the default random engine.
template<typename Type, typename CustomRandomGenerator = Random_generator&>
Type	Gudhi::random::get_uniform (const Type &min, const Type &max, CustomRandomGenerator &&rng=get_default_random())
	Generates a random number in the range [min, max].
template<typename Type, typename CustomRandomGenerator = Random_generator&>
std::vector< Type >	Gudhi::random::get_uniform_range (std::size_t nbr, const Type &min, const Type &max, CustomRandomGenerator &&rng=get_default_random())
	Generates a vector of N random numbers in the range [min, max].

Detailed Description

Some of the GUDHI functionnalities are using randomness. Here is a list of classes and methods that are using internally Gudhi::random::get_default_random (and are thus affected by Gudhi::random::set_seed):

• Gudhi::subsampling::choose_n_farthest_points
• Gudhi::subsampling::pick_n_random_points
• Gudhi::Persistence_representations::Sliced_Wasserstein
• Gudhi::cover_complex::Cover_complex

In order to reproduce the results, a specific GUDHI random generator is available, and one can set its seed:

#include <gudhi/random.h>
 
// Set the seed for the default generator that is used internally in GUDHI
Gudhi::random::set_seed(42);

Typedef Documentation

Random_generator

using Gudhi::random::Random_generator = std::mt19937_64

The default random number generator type returned by get_default_random

Function Documentation

get_default_random()

Random_generator & Gudhi::random::get_default_random ( )

inline

Returns a thread-local default random number generator instance.

Returns

A reference to the thread-local default random instance.

get_uniform()

template<typename Type, typename CustomRandomGenerator = Random_generator&>

Type Gudhi::random::get_uniform	(	const Type &	min,
		const Type &	max,
		CustomRandomGenerator &&	rng = get_default_random() )

Generates a random number in the range [min, max].

Template Parameters

Type	The type of the random number (must be integral or floating-point).
CustomRandomGenerator	The type of the random generator. Default is Random_generator.

Parameters

min	The minimum value (inclusive).
max	The maximum value (inclusive for integral types, but exclusive for floating-point types).
rng	A random generator. Use the default one if not set.

Returns

A random number of type Type in the range [min, max].

get_uniform_range()

template<typename Type, typename CustomRandomGenerator = Random_generator&>

std::vector< Type > Gudhi::random::get_uniform_range	(	std::size_t	nbr,
		const Type &	min,
		const Type &	max,
		CustomRandomGenerator &&	rng = get_default_random() )

Generates a vector of N random numbers in the range [min, max].

Template Parameters

Type	The type of the random numbers (must be integral or floating-point).
CustomRandomGenerator	The type of the random generator. Default is Random_generator.

Parameters

nbr	The number of random numbers to generate.
min	The minimum value (inclusive).
max	The maximum value (inclusive for integral types, but exclusive for floating-point types).
rng	A random generator. Use the default one if not set.

Returns

A vector of random numbers of type Type in the range [min, max].

Examples

Random_bitmap_cubical_complex.cpp.

set_seed()

void Gudhi::random::set_seed

(

Random_generator::result_type

seed

)

Sets the seed for the default random engine.

Parameters

seed	The new seed value.