System for consistent seeding of random number generators. More...

#include <RandomNumberSeedService.h>

Inheritance diagram for fire::RandomNumberSeedService:

Collaboration diagram for fire::RandomNumberSeedService:

Public Member Functions
	RandomNumberSeedService (const fire::config::Parameters &parameters)
	Create the random number seed service conditions object. More...

virtual void	onNewRun (RunHeader &header) final override
	Configure the seed service when a new run starts. More...

uint64_t	getSeed (const std::string &name) const
	Access a given seed by name. More...

std::vector< std::string >	getSeedNames () const
	Get a list of all the known seeds. More...

uint64_t	getRootSeed () const
	Access the root seed. More...

virtual std::pair< const ConditionsObject *, ConditionsIntervalOfValidity >	getCondition (const EventHeader &context) final override
	Get the seed service as a conditions object. More...

virtual void	release (const ConditionsObject *co) final override
	This object is both the provider of the seed service and the conditions object itself, so it does nothing when asked to release the object. More...

void	stream (std::ostream &s) const
	Stream the configuration of this object to the input ostream. More...

Public Member Functions inherited from fire::ConditionsObject
	ConditionsObject (const std::string &name) noexcept
	Define the name of the condition.

virtual	~ConditionsObject ()=default
	Default destructor. More...

std::string	getName () const
	Get the name of this object. More...

Public Member Functions inherited from fire::ConditionsProvider
	ConditionsProvider (const fire::config::Parameters &ps)
	Configure the registered provider. More...

virtual	~ConditionsProvider ()=default
	default destructor, virtual so derived types can be destructed

virtual void	onProcessStart ()
	Callback for the ConditionsProvider to take any necessary action when the processing of events starts.

virtual void	onProcessEnd ()
	Callback for the ConditionsProvider to take any necessary action when the processing of events finishes, such as closing database connections.

const std::string &	getConditionObjectName () const
	Get the condition object available from this provider.

const std::string &	getTagName () const
	Access the tag name.

virtual void	attach (Conditions *c) final
	Attach the central conditions system to this provider.

Static Public Attributes
static const std::string	CONDITIONS_OBJECT_NAME
	Conditions object name. More...

Private Attributes
bool	initialized_ {false}
	whether the root seed has been initialized

int	mode_ {0}
	what mode of root seed are we using

uint64_t	root_ {0}
	what the root seed actually is

std::map< std::string, uint64_t >	seeds_
	cache of seeds by name

Friends
std::ostream &	operator<< (std::ostream &s, const RandomNumberSeedService &o)
	Output streaming operator. More...

Additional Inherited Members
Public Types inherited from fire::ConditionsProvider
using	Factory = factory::Factory< ConditionsProvider, std::shared_ptr< ConditionsProvider >, const config::Parameters & >
	The factory type that can create this class. More...

Protected Member Functions inherited from fire::ConditionsProvider
std::pair< const ConditionsObject *, ConditionsIntervalOfValidity >	requestParentCondition (const std::string &name, const EventHeader &context)
	Request another condition needed to construct this condition. More...

Protected Attributes inherited from fire::ConditionsProvider
logging::logger	theLog_
	The logger for this ConditionsProvider.

Detailed Description

System for consistent seeding of random number generators.

The system can be configured in a number of different ways. In general, seeds are constructed based on a root seed. That root seed can be constructed in a number of ways, chosen in the python configuration. (a) The root seed can be the run number of the first run observed by the service ("Run") (b) The root seed can be based on the current time ("Time") (c) The root seed can be provided in the python configuration ("External")

Individual seeds are then constructed using the root seed and a simple hash based on the name of the seed.

Seeds can also be specified in the python file (using the 'override' function), in which case no autoseeding will be performed.

Constructor & Destructor Documentation

◆ RandomNumberSeedService()

fire::RandomNumberSeedService::RandomNumberSeedService ( const fire::config::Parameters & parameters )

Create the random number seed service conditions object.

This is where we decide what seed mode we will be running in.

Parameters

[in]	name	the name of this provider
[in]	tagname	the name of the tag generation of this condition
[in]	parameters	configuration parameters from python
[in]	process	reference to the running process object

Member Function Documentation

◆ getCondition()

std::pair< const ConditionsObject *, ConditionsIntervalOfValidity > fire::RandomNumberSeedService::getCondition ( const EventHeader & context )

finaloverridevirtual

Get the seed service as a conditions object.

This object is both the provider of the seed service and the conditions object itself, so after checking if it has been initialized, we return a refernce to ourselves with the unlimited interval of validity.

Parameters

[in] context EventHeader for the event context

Returns: reference to ourselves and unlimited interval of validity

Implements fire::ConditionsProvider.

◆ getRootSeed()

uint64_t fire::RandomNumberSeedService::getRootSeed ( ) const

inline

Access the root seed.

Returns: root seed that is used to derive all other seeds

◆ getSeed()

uint64_t fire::RandomNumberSeedService::getSeed ( const std::string & name ) const

Access a given seed by name.

Checks the cache for the input name. If the input name is not in the cache, it generates the seed for that name by combining the root seed with a hash of the name.

Parameters

[in] name Name of seed

Returns: seed derived from root seed using the input name

◆ getSeedNames()

std::vector< std::string > fire::RandomNumberSeedService::getSeedNames ( ) const

Get a list of all the known seeds.

Returns: vector of seed names that have already been requested (in cache)

◆ onNewRun()

void fire::RandomNumberSeedService::onNewRun ( RunHeader & header )

finaloverridevirtual

Configure the seed service when a new run starts.

If we are using the run number as the root seed, then we get the run number and set the root seed to it.

No matter what, we put the root seed into the RunHeader to be persisted into the output file.

Parameters

[in,out] header RunHeader for the new run that is starting

Reimplemented from fire::ConditionsProvider.

◆ release()

virtual void fire::RandomNumberSeedService::release ( const ConditionsObject * co )

inlinefinaloverridevirtual

This object is both the provider of the seed service and the conditions object itself, so it does nothing when asked to release the object.

Parameters

[in] co ConditionsObject to release, unused

Reimplemented from fire::ConditionsProvider.

◆ stream()

void fire::RandomNumberSeedService::stream ( std::ostream & s ) const

Stream the configuration of this object to the input ostream.

Parameters

[in,out] s output stream to print this object to

Friends And Related Function Documentation

◆ operator<<

std::ostream & operator<<	(	std::ostream &	s,
		const RandomNumberSeedService &	o
	)

friend

Output streaming operator.

See also: fire::RandomNumberSeedService::stream

Parameters

[in]	s	output stream to print to
[in]	o	seed service to print

Returns: modified output stream

Member Data Documentation

◆ CONDITIONS_OBJECT_NAME

const std::string fire::RandomNumberSeedService::CONDITIONS_OBJECT_NAME

static

Initial value:

=

"RandomNumberSeedService"

Conditions object name.

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

include/fire/RandomNumberSeedService.h
src/fire/RandomNumberSeedService.cxx

Public Member Functions

Static Public Attributes

Private Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ RandomNumberSeedService()

Member Function Documentation

◆ getCondition()

◆ getRootSeed()

◆ getSeed()

◆ getSeedNames()

◆ onNewRun()

◆ release()

◆ stream()

Friends And Related Function Documentation

◆ operator<<

Member Data Documentation

◆ CONDITIONS_OBJECT_NAME