An interaction model which recreates a social media feed to dictate interactions. More...

Inheritance diagram for Social_Media_no_followers:

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Collaboration diagram for Social_Media_no_followers:

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Classes
struct	default_media_user
	Class that implements the behavior of a user on the social media. More...

class	event_container
	Container for media_events with various restrictions More...

struct	media_event
	A data structure to represent a tweet, facebook post, or any other social media event. More...

struct	media_user
	Base class for the behavior of users on the social media. More...

Public Member Functions
void	load_events (const std::string &fname, const dynet::datetime &start_time, float time_conversion, const std::map< std::string, unsigned int > &agent_mask=std::map< std::string, unsigned int >())
	Parses the content of a json file and loads the information into Social_Media_no_followers::list_of_events. More...

virtual media_event *	create_post (unsigned int knowledge_index, unsigned int id)
	Creates a post event and adds it to Social_Media_no_followers::list_of_events. More...

virtual media_event *	create_response (unsigned int id, media_event *parent)
	Creates a response event based on the parent event and adds it to Social_Media_no_followers::list_of_events. More...

virtual media_event *	create_quote (unsigned int id, media_event *parent)
	Creates a quote event based on the parent event and adds it to Social_Media_no_followers::list_of_events. More...

virtual media_event *	create_reply (unsigned int id, media_event *parent)
	Creates a reply event based on the parent event and adds it to Social_Media_no_followers::list_of_events. More...

virtual media_event *	create_repost (unsigned int id, media_event *parent)
	Creates a quote event based on the parent event and adds it to Social_Media_no_followers::list_of_events. More...

virtual void	finalize_event (media_event *_event)
	Allows each model to intercept the created event. More...

void	check_list_order () const
	Checks the list of events to make sure the time stamps are sorted in descending order. More...

Social_Media_no_followers::media_user &	user (unsigned int index)

	Social_Media_no_followers (const std::string &_media_name, InteractionItem::item_keys event_key, const dynet::ParameterMap &parameters, Construct &_construct)
	Base constructor for any social media model. More...

virtual	~Social_Media_no_followers ()
	All pointers in Social_Media_with_followers::users are deallocated.

virtual media_user *	get_default_media_user (const Node &node)
	Gets the default media user for a social media class. More...

void	think (void) override
	Agents read events in their feed and create messages based on the read events. More...

void	initialize (void) override
	Loads users using Social_Media_no_followers::load_user and adds Knowledge_Parser to Construct::message_parsers if one is not present. More...

void	communicate (const InteractionMessage &msg) override
	Parses messages that contain the Social_Media_no_followers::event key in their attributes. If the event contains the attribute, media_user::(read, reply, quote, and repost) are called from the receiver's index in Social_Media_no_followers::users More...

void	cleanup (void) override
	Feeds are updated, list_of_events::removed_events are cleared, and events are erased from list_of_events that have have become inactive. More...

virtual void	append_message (media_event *_event, InteractionMessage &msg)
	Appends the array of InteractionItems based on the submitted event and the intended receiver of the message. More...

virtual InteractionItem	convert_to_InteractionItem (media_event *_event, unsigned int sender_index, unsigned int receiver_index) const
	Copies some or all information from the submitted event based on the sender's and receiver's node attributes. More...

virtual int	get_feed_priority (const media_event &_event, unsigned int user)
	Returns 10 if the user is mentioned by the event or if the event is a reply to an event authored by the user. Returns 100 otherwise. More...

virtual void	update_event_scores ()
	Goes through all events and updates media_event::score to media_event::child_size * media_event::time_stamp. More...

virtual void	random_event_swapping (unsigned int user_index)
	Randomly swaps 10% of events in the user's feed. More...

virtual void	update_feeds (float new_events_timestamp)
	Updates each user's feeds. More...

template<typename function >
auto	get_events (function filter)

Public Member Functions inherited from Model
	Model (Construct &_construct)
	Constructor for all models in Construct. More...

virtual	~Model (void)
	Virtual Deconstructor. More...

virtual void	initialize (void)
	Function called once before any simulation cycles begin. More...

virtual void	think (void)
	First function called in a simulation cycle. More...

virtual void	update (void)
	Function called after the think functions in a simulation cycle. More...

virtual bool	intercept (InteractionItem &item, unsigned int sender, unsigned int receiver, const CommunicationMedium *medium)
	Allows for models to effect change to items created by other models. More...

virtual void	communicate (const InteractionMessage &msg)
	Function called after the update functions in a simulation cycle. More...

virtual void	cleanup (void)
	Function called after the Model::communicate functions in a simulation cycle. More...

void	add_base_model_to_model_manager (const std::string &base_model_name)
	Adds a derived model under the name of the base model and disables the model manager from calling its functions.

Public Attributes
event_container	list_of_events
	The list of all current events in this social media. New events should be added to the front of this list.

const Nodeset &	agents = ns_manager.get_nodeset(nodeset_names::agents)

const Nodeset &	knowledge = ns_manager.get_nodeset(nodeset_names::knowledge)

const CommunicationMedium	medium
	The medium used for all messages created by this model.

const InteractionItem::item_keys	event_key
	The item key added to all messages created by this model.

std::vector< std::vector< media_event * > >	users_feed
	Each user's feed of events with the first dimension corresponding to each user. More...

std::vector< unsigned int >	read_count

float	age
	The maximum time a post can exist without its tree being added to.

float	dt
	The time duration between time steps.

float	time = 0.0f
	The current time period.

std::string	media_name
	The prefix for some of the node attributes names parsed by the media_user class.

Graph< bool > &	knowledge_net = graph_manager.load_required(graph_names::knowledge, agents, knowledge)
	Pointer to the graph with name "knowledge network".

const Graph< bool > *	active_agents = graph_manager.load_optional(graph_names::active, true, agents, sparse, ns_manager.get_nodeset(nodeset_names::time), sparse)
	Pointer to the graph with name "agent active time network".

std::vector< media_user * >	users
	The list of users. More...

std::function< bool(media_event &)>	current_timestep = [this](media_event& _event) { return _event.time_stamp > time - 0.5f * dt; }

std::function< bool(media_event &)>	previous_timestep = [this](media_event& _event) { return _event.time_stamp > time - 1.5f * dt; }

std::function< bool(media_event &)>	active = [this](media_event& _event) { return _event.last_used > time - age; }

std::function< void(Social_Media_no_followers *, unsigned int)>	feed_update_output

std::function< void(Social_Media_no_followers *)>	cleanup_output

Public Attributes inherited from Model
Construct &	construct

GraphManager &	graph_manager

NodesetManager &	ns_manager

Random &	random

bool	valid
	If member is false, the model's functions are not called.

Detailed Description

An interaction model which recreates a social media feed to dictate interactions.

This model uses the media_event data structure to represent and track the event tree/cascade. Agents create events which are stored in Social_Media_no_followers::list_of_events. These events can be created sponateously or in response to reading an event. What actions are taken depends on how classes derived from media_user implement the virtual functions. Future developers may wish to modify the underlying structure of this model. For that reason, a set of virtual functions have been implemented for modifying how feeds are updated, and how InteractionMessagess are created based on read events.

Updating feeds is handled by Social_Media_no_followers::update_feeds and dictate how the feeds are ordered. New events are added to the feed and old/read event are removed. An event is old when Social_Media_no_followers::time * Social_Media_no_followers::dt - media_event::last_used > Social_Media_no_followers::age. New events are grouped by user by events that mention that user or responds to them. The other group contains all other events. Both groups are sorted by their score which is equal to media_event::time_stamp * media_event::child_size(). The groups are then combined for each user with mentions and responses first. Finally 10% of the entire feed is stochastically swapped to sprinkle new content into the front of a users feed.

All information that is to be conveyed in messages is handled by Social_Media_no_followers::append_message. Because additional information may added to events than what is currently developed, this will allow developers to add the additional information in the messages being passed around based on the event being read. This function only appends the message items and does not create the message that will be added to the message queue. The message sender is the author of the event being read, and is not always the case that the event submitted to the function is the same event being read. In the case where the events differ, the author of that event should be added as an alter in the InteractionItem.

Social_Media_no_followers::media_user represents the agents operating on this social media. The base class provides a template for how the Social_Media asks how a user should respond to information. Classes derived from Social_Media_no_followers::media_user such as Social_Media_no_followers::default_media_user details the behavior of agents. Agents can be asked how many events they wish to read via Social_Media_no_followers::media_user::get_read_count(). Similarily an agent can be asked by Social_Media_no_followers whether they wish to reply to an event they're reading via Social_Media_no_followers::media_user::reply(). Customs users can be created by replacing Social_Media_no_followers::load_user.

Constructor & Destructor Documentation

◆ Social_Media_no_followers()

Social_Media_no_followers::Social_Media_no_followers	(	const std::string &	_media_name,
		InteractionItem::item_keys	event_key,
		const dynet::ParameterMap &	parameters,
		Construct &	_construct
	)

Base constructor for any social media model.

This class does not define the model's name. Instead derived classes must do so when initializing the Model constructor.

Parameters

_media_name	The name of the social media and is stored in Social_Media_with_followers::media_name. This affects the node attributes that are searched for in defining a Social_Media_no_followers::default_media_user.
parameters	A parameter map that should contain the keys "interval time duration" and "maximum post inactivity" as floats.
_construct	The construct pointer that is passed to the Model constructor.
event_key	The item key that the social media uses to identify an InteractionItem that contains one of its feed indexes.

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Member Function Documentation

◆ append_message()

void Social_Media_no_followers::append_message	(	media_event *	_event,
		InteractionMessage &	msg
	)

virtual

Appends the array of InteractionItems based on the submitted event and the intended receiver of the message.

summary> Gathers the set of events that an agent should read based on what event they just read.

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◆ check_list_order()

void Social_Media_no_followers::check_list_order ( ) const

Checks the list of events to make sure the time stamps are sorted in descending order.

To avoid floating point percision conflicts an event's time stamp is compared with the next event's time stamp - dt*.5.

summary>

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◆ cleanup()

void Social_Media_no_followers::cleanup ( void )

overridevirtual

Feeds are updated, list_of_events::removed_events are cleared, and events are erased from list_of_events that have have become inactive.

Reimplemented from Model.

Reimplemented in Social_Media_with_followers.

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◆ communicate()

void Social_Media_no_followers::communicate ( const InteractionMessage & msg )

overridevirtual

Parses messages that contain the Social_Media_no_followers::event key in their attributes. If the event contains the attribute, media_user::(read, reply, quote, and repost) are called from the receiver's index in Social_Media_no_followers::users

Reimplemented from Model.

Reimplemented in Social_Media_with_followers.

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◆ convert_to_InteractionItem()

InteractionItem Social_Media_no_followers::convert_to_InteractionItem	(	media_event *	_event,
		unsigned int	sender_index,
		unsigned int	receiver_index
	)		const

virtual

Copies some or all information from the submitted event based on the sender's and receiver's node attributes.

If the event's user is the receiver, an empty item is returned. If the receiver's node attribute "can receive knowledge" is false, all knowledge and knowledge trust information is removed. If the receiver's node attribute "can receive knowledge trust" is false, all knowledge trust information is removed. If the receiver can receive both knowledge and knowledge trust, but the event's user does not equal the sender, the sender index is added to InteractionItem::indexes under the key InteractionItem::item_keys::alter.

Returns: An InteractionItem with content copied from the submitted event with some, none, or all information filtered.

Reimplemented in SM_nf_emotions, and SM_wf_emotions.

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◆ create_post()

virtual media_event * Social_Media_no_followers::create_post	(	unsigned int	knowledge_index,
		unsigned int	id
	)

inlinevirtual

Creates a post event and adds it to Social_Media_no_followers::list_of_events.

Set required member values such as type, id, time_stamp, last_used, and sets the knowledge information.

Parameters

knowledge_index	Uses InteractionItem::set_knowledge_item to set the knowledge index of the event.
id	Agent index of the event's author.

Returns: Returns the newly created event.

Example

int main()
{
    Social_Media_no_followers& media;
 
    unsigned int agent_index = 4;
    unsigned int knowledge_index = 5;
    float knowledge_trust = 0.3;
 
    new_event = media.create_post(knowledge_index, agent_index);
    new_event.set_knowledge_trust_item(knowledge_index, knowledge_trust);
}

Complexity

Constant

Iterator validity

No changes. list_of_events.begin returns a different iterator value.

Exception Safety

No-throw guarantee: this member function never throws exceptions.

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◆ create_quote()

virtual media_event * Social_Media_no_followers::create_quote	(	unsigned int	id,
		media_event *	parent
	)

inlinevirtual

Creates a quote event based on the parent event and adds it to Social_Media_no_followers::list_of_events.

Uses Social_Media_no_followers::create_response to create the event, sets the event's type to media_event::event_type::quote, and adds the newly created event to the parent's quotes.

Parameters

parent	Pointer to the parent event for this response.
id	Agent index of the event's author.

Returns: Returns the newly created event.

Example

int main()
{
    Social_Media_no_followers& media;
 
    unsigned int agent_index = 4;
    media_event* parent;
    float knowledge_trust = 0.3;
 
    new_event = media.create_quote(knowledge_index, parent);
    new_event.set_knowledge_trust_item(knowledge_index, knowledge_trust);
}

Complexity

Constant

Iterator validity

No changes. list_of_events.begin returns a different iterator value.

Exception Safety

No-throw guarantee: this member function never throws exceptions.

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◆ create_reply()

virtual media_event * Social_Media_no_followers::create_reply	(	unsigned int	id,
		media_event *	parent
	)

inlinevirtual

Creates a reply event based on the parent event and adds it to Social_Media_no_followers::list_of_events.

Uses Social_Media_no_followers::create_response to create the event, sets the event's type to media_event::event_type::quote, and adds the newly created event to the parent's quotes.

Parameters

parent	Pointer to the parent event for this response.
id	Agent index of the event's author.

Returns: Returns the newly created event.

Example

int main()
{
    Social_Media_no_followers& media;
 
    unsigned int agent_index = 4;
    media_event* parent;
    float knowledge_trust = 0.3;
 
    new_event = media.create_quote(knowledge_index, parent);
    new_event.set_knowledge_trust_item(knowledge_index, knowledge_trust);
}

Complexity

Constant

Iterator validity

No changes. list_of_events.begin returns a different iterator value.

Exception Safety

No-throw guarantee: this member function never throws exceptions.

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◆ create_repost()

virtual media_event * Social_Media_no_followers::create_repost	(	unsigned int	id,
		media_event *	parent
	)

inlinevirtual

Creates a quote event based on the parent event and adds it to Social_Media_no_followers::list_of_events.

Uses Social_Media_no_followers::create_response to create the event, sets the event's type to media_event::event_type::quote, and adds the newly created event to the parent's quotes.

Parameters

parent	Pointer to the parent event for this response.
id	Agent index of the event's author.

Returns: Returns the newly created event.

Example

int main()
{
    Social_Media_no_followers& media;
 
    unsigned int agent_index = 4;
    media_event* parent;
    float knowledge_trust = 0.3;
 
    new_event = media.create_quote(knowledge_index, parent);
    new_event.set_knowledge_trust_item(knowledge_index, knowledge_trust);
}

Complexity

Constant

Iterator validity

No changes. list_of_events.begin returns a different iterator value.

Exception Safety

No-throw guarantee: this member function never throws exceptions.

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◆ create_response()

virtual media_event * Social_Media_no_followers::create_response	(	unsigned int	id,
		media_event *	parent
	)

inlinevirtual

Creates a response event based on the parent event and adds it to Social_Media_no_followers::list_of_events.

Set required member values such as id, time_stamp, last_used, and sets the knowledge information. The event type is expected to be set by the calling function. Additionally, handles linking the created event to the parent event. The calling function is expected to link the parent event to the created event by placing the created event in the appropriate data structure in the parent event. The last_used value is also updated for each event in the root event's tree.

Parameters

parent	Pointer to the parent event for this response.
id	Agent index of the event's author.

Returns: Returns the newly created event.

Example

int main()
{
    Social_Media_no_followers& media;
 
    unsigned int agent_index = 4;
    media_event* parent;
 
    new_event = media.create_response(agent_index, parent);
    new_event.type = media_event::event_type::reply;
    parent->replies.insert(new_event);
}

Complexity

Linear with number of event's in the root event's tree.

Iterator validity

No changes. list_of_events.begin returns a different iterator value.

Exception Safety

No-throw guarantee: this member function never throws exceptions.

Reimplemented in Reddit.

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◆ finalize_event()

virtual void Social_Media_no_followers::finalize_event ( media_event * _event )

inlinevirtual

Allows each model to intercept the created event.

Models may add, remove, or modify content in the event or completely stop its creation all together. This function should be called on every event created after the event has been populated with information. By default, this function is called at the end of Social_Media_no_followers::default_media_user::enrich_event.

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◆ get_default_media_user()

virtual media_user * Social_Media_no_followers::get_default_media_user ( const Node & node )

inlinevirtual

Gets the default media user for a social media class.

Reimplemented in SM_nf_emotions, SM_wf_emotions, Reddit, and Social_Media_with_followers.

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◆ get_feed_priority()

int Social_Media_no_followers::get_feed_priority	(	const media_event &	_event,
		unsigned int	user
	)

virtual

Returns 10 if the user is mentioned by the event or if the event is a reply to an event authored by the user. Returns 100 otherwise.

Reimplemented in SM_wf_emotions, Reddit, and Social_Media_with_followers.

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◆ initialize()

void Social_Media_no_followers::initialize ( void )

overridevirtual

Loads users using Social_Media_no_followers::load_user and adds Knowledge_Parser to Construct::message_parsers if one is not present.

Reimplemented from Model.

Reimplemented in Facebook_wf, and Twitter_wf.

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◆ load_events()

void Social_Media_no_followers::load_events	(	const std::string &	fname,
		const dynet::datetime &	start_time,
		float	time_conversion,
		const std::map< std::string, unsigned int > &	agent_mask = `std::map<std::string, unsigned int>()`
	)

inline

Parses the content of a json file and loads the information into Social_Media_no_followers::list_of_events.

The json is assumed to be in the Twitter API v2 format. Construct specific information such as knowledge is parsed in the "entities" element in each event. Ex. "entities": {"mentions": ["mentioned_user"], "attributes": ["knowledge"], "indexes": {"knowledge":4}} After all events are loaded, update_feeds is called with "start_time" as its argument.

Parameters

fname	Name of the json file to be loaded and may contain the full path to the file.
start_time	The time that corresponds to the initialization time step which is one time step before time node at index 0.
time_conversion	The conversion between seconds and Social_Media_no_followers::dt. Example if Social_Media_no_followers::dt equals 2 hours, time_conversion should equal 7200.
agent_mask	An optional parameter that is used to assign indexes for authors. When used, the agent_mask is searched for the key equal to "author_id" value in each corrsponding json element. The index corresponding index for that key is then used as the index for the loaded event's user. Otherwise, the agent nodeset is searched for a node matching the "author_id" value and that node's index is used for the event's user.

Exception Safety

All events in the json file must have an "id" field. A #dynet::could_not_find_property_key is thrown if the field is not found. Events that do not contain "created_at" or "author_id" are discarded.

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◆ random_event_swapping()

void Social_Media_no_followers::random_event_swapping ( unsigned int user_index )

virtual

Randomly swaps 10% of events in the user's feed.

Reimplemented in Reddit.

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◆ think()

void Social_Media_no_followers::think ( void )

overridevirtual

Agents read events in their feed and create messages based on the read events.

Reimplemented from Model.

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◆ update_event_scores()

void Social_Media_no_followers::update_event_scores ( )

virtual

Goes through all events and updates media_event::score to media_event::child_size * media_event::time_stamp.

Reimplemented in Reddit.

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◆ update_feeds()

void Social_Media_no_followers::update_feeds ( float new_events_timestamp )

virtual

Updates each user's feeds.

For each user, only feed items after the index contained in the user's corresponding element in read_count are kept in their feed. Additionally new events created in this time step are added to their feed. Events are then grouped by using Social_Media_no_followers::get_feed_priority. Events with a similar integer return from this function are grouped with any negative value return being discarded. Each group is then sorted using Social_Media_no_followers::update_event_scores. These groups are then ordered into the feed with the lowest priority values being first to be read. Finally 10% of events are randomly swapped using Social_Media_no_followers::random_event_swapping.

Parameters

new_events_timestamp Any events with time stamp greater than this value are treated as new events and added to each user's feeds.

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Member Data Documentation

◆ agents

const Nodeset& Social_Media_no_followers::agents = ns_manager.get_nodeset(nodeset_names::agents)

summary>

◆ users

std::vector<media_user*> Social_Media_no_followers::users

The list of users.

summary>

◆ users_feed

std::vector<std::vector<media_event*> > Social_Media_no_followers::users_feed

Each user's feed of events with the first dimension corresponding to each user.

summary>

Classes

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Social_Media_no_followers()

Member Function Documentation

◆ append_message()

◆ check_list_order()

◆ cleanup()

◆ communicate()

◆ convert_to_InteractionItem()

◆ create_post()

◆ create_quote()

◆ create_reply()

◆ create_repost()

◆ create_response()

◆ finalize_event()

◆ get_default_media_user()

◆ get_feed_priority()

◆ initialize()

◆ load_events()

◆ random_event_swapping()

◆ think()

◆ update_event_scores()

◆ update_feeds()

Member Data Documentation

◆ agents

◆ users

◆ users_feed