this class does not give synced random results derived classes might do. More...

#include <random.hpp>

Inheritance diagram for randomness::rng:

Public Types
using	result_type = uint32_t

Public Member Functions
	rng ()

uint32_t	next_random ()
	Provides the next random draw. More...

virtual	~rng ()

unsigned int	get_random_calls () const
	Provides the number of random calls to the rng in this context. More...

int	get_random_int (int min, int max)

bool	get_random_bool (double probability)
	This helper method returns true with the probability supplied as a parameter. More...

double	get_random_double ()
	This helper method returns a floating-point number in the range [0,1[. More...

template<typename T >
T::difference_type	get_random_element (T first, T last)
	This helper method selects a random element from a container of floating-point numbers. More...

uint32_t	operator() ()

virtual bool	is_networked () const
	Is this random source networked? If it is it's very important we do actually use this random source to stay in-sync. More...

Static Public Member Functions
static rng &	default_instance ()

Protected Member Functions
virtual uint32_t	next_random_impl ()=0

Protected Attributes
unsigned int	random_calls_

Private Types
using	base = std::numeric_limits< uint32_t >

Private Member Functions
int	get_random_int_in_range_zero_to (int max)
	Does the hard work of get_random_int. More...

Detailed Description

this class does not give synced random results derived classes might do.

Definition at line 27 of file random.hpp.

Member Typedef Documentation

◆ base

using randomness::rng::base = std::numeric_limits<uint32_t>

private

Definition at line 29 of file random.hpp.

◆ result_type

using randomness::rng::result_type = uint32_t

Definition at line 78 of file random.hpp.

Constructor & Destructor Documentation

◆ rng()

randomness::rng::rng ( )

Definition at line 62 of file random.cpp.

◆ ~rng()

randomness::rng::~rng ( )

virtual

Definition at line 68 of file random.cpp.

Member Function Documentation

◆ default_instance()

rng & randomness::rng::default_instance ( )

static

Definition at line 73 of file random.cpp.

Referenced by unit_animation_component::choose_animation(), choose_track(), ai::default_recruitment::recruitment::get_best_leader_from_ratio_scores(), leave_synced_context::leave_synced_context(), unit_animation::matches(), editor::editor_action_shuffle_area::perform_without_undo(), pick_one(), display::reinit_flags_for_team(), play_controller::select_music(), gui2::tip_of_the_day::shuffle(), and soundsource::positional_source::update().

◆ get_random_bool()

bool randomness::rng::get_random_bool ( double probability )

This helper method returns true with the probability supplied as a parameter.

Parameters

probability The probability of returning true, from 0 to 1.

Definition at line 136 of file random.cpp.

References get_random_double().

◆ get_random_calls()

unsigned int randomness::rng::get_random_calls ( ) const

Provides the number of random calls to the rng in this context.

Note that this may be different from the number of random calls to the underlying rng, and to the random_calls number in save files!

Definition at line 79 of file random.cpp.

References random_calls_.

◆ get_random_double()

double randomness::rng::get_random_double ( )

This helper method returns a floating-point number in the range [0,1[.

Definition at line 111 of file random.cpp.

References next_random().

Referenced by ai::default_recruitment::recruitment::do_randomness(), get_random_bool(), and get_random_element().

◆ get_random_element()

template<typename T >

T::difference_type randomness::rng::get_random_element	(	T	first,
		T	last
	)

This helper method selects a random element from a container of floating-point numbers.

Every number has a probability to be selected equal to the number itself (e.g. a number of 0.1 is selected with a probability of 0.1). The sum of numbers should be one.

Parameters

first	Iterator to the beginning of the container
last	Iterator to the end of the container

Returns: The index of the selected number

Definition at line 111 of file random.hpp.

References get_random_double().

◆ get_random_int()

int randomness::rng::get_random_int	(	int	min,
		int	max
	)

inline

This helper method provides a random int from the underlying generator,

using results of next_random in a manner guaranteed to be cross platform. The result will be random in range [min,max] inclusive.

Parameters

min	The minimum value produced.
max	The maximum value produced.

Definition at line 51 of file random.hpp.

References get_random_int_in_range_zero_to().

Referenced by unit_animation_component::choose_animation(), choose_track(), wfl::operator_expression::dice_roll(), generate_gender(), unit::generate_traits(), ai::default_recruitment::recruitment::get_random_pattern_type_if_exists(), ai::helper_advance_unit(), pick_one(), display::reinit_flags_for_team(), play_controller::select_music(), saved_game::set_random_seed(), and soundsource::positional_source::update().

◆ get_random_int_in_range_zero_to()

int randomness::rng::get_random_int_in_range_zero_to ( int max )

private

Does the hard work of get_random_int.

This code is based on the boost implementation of uniform_smallint.

The result will be random in range [0,max] inclusive.

Parameters

max	The maximum value produced.

http://www.boost.org/doc/libs/1_55_0/boost/random/uniform_smallint.hpp Using that code would be ideal, except that boost, and C++11, do not guarantee that it will work the same way on all platforms, or that the results may not be different in future versions of the library. The simplified version I have written should work the same on all platforms, which is the most important thing for us. The existence of "modulo bias" seems less important when we have moved to std::mt19937, since it guarantees that there are no "bad bits" and has a very large range.

If a standard cross platform version becomes available then this should be replaced.

Definition at line 105 of file random.cpp.

References next_random().

Referenced by get_random_int().

◆ is_networked()

virtual bool randomness::rng::is_networked ( ) const

inlinevirtual

Is this random source networked? If it is it's very important we do actually use this random source to stay in-sync.

Reimplemented in randomness::synced_rng.

Definition at line 89 of file random.hpp.

◆ next_random()

uint32_t randomness::rng::next_random ( )

Provides the next random draw.

This is raw PRG output.

Definition at line 84 of file random.cpp.

References next_random_impl(), and random_calls_.

Referenced by get_random_double(), get_random_int_in_range_zero_to(), context_free_grammar_generator::init_seed(), lua_mathx::intf_random(), markov_generate_name(), operator()(), and tod_manager::resolve_random().

◆ next_random_impl()

virtual uint32_t randomness::rng::next_random_impl ( )

protectedpure virtual

Implemented in randomness::synced_rng, randomness::rng_proxy, and randomness::rng_deterministic.

Referenced by next_random().

◆ operator()()

uint32_t randomness::rng::operator() ( )

inline

Definition at line 81 of file random.hpp.

References next_random().

Member Data Documentation

◆ random_calls_

unsigned int randomness::rng::random_calls_

protected

Definition at line 93 of file random.hpp.

Referenced by get_random_calls(), and next_random().

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

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Private Types

Private Member Functions

Detailed Description

Member Typedef Documentation

◆ base

◆ result_type

Constructor & Destructor Documentation

◆ rng()

◆ ~rng()

Member Function Documentation

◆ default_instance()

◆ get_random_bool()

◆ get_random_calls()

◆ get_random_double()

◆ get_random_element()

◆ get_random_int()

◆ get_random_int_in_range_zero_to()

◆ is_networked()

◆ next_random()

◆ next_random_impl()

◆ operator()()

Member Data Documentation

◆ random_calls_