Event Template

event_template is the base class for all user-defined event types. It manages the mapping between ROOT branch/leaf data (stored in element_t structs) and the C++ particle collections registered by subclasses, and exposes kinematic metadata via cproperty accessors.

Class: `event_template`

Header: <templates/event_template.h>

Inheritance: tools

Properties

Property	Type	Description
`trees`	`std::vector<std::string>`	List of ROOT tree names this event reads from. Writable.
`branches`	`std::vector<std::string>`	List of ROOT branch-path filters. Writable.
`leaves`	`std::vector<std::string>`	Derived list of fully-resolved ROOT leaf paths (read-only; computed from registered particles).
`name`	`std::string`	Human-readable event-class name (used as HDF5 dataset label). Writable.
`hash`	`std::string`	18-character hex identifier for this event. Settable and gettable.
`tree`	`std::string`	The ROOT tree name under which this event was read. Gettable/Settable.
`weight`	`double`	Monte Carlo event weight. Default `0.0`.
`index`	`long`	Sequential event index within the file. Default `0`.

Public Fields

Field	Type	Description
`m_trees`	`std::map<std::string, std::string>`	Internal map of tree-key → ROOT tree name.
`m_branches`	`std::map<std::string, std::string>`	Internal map of branch-key → ROOT branch name.
`m_leaves`	`std::map<std::string, std::string>`	Resolved leaf-key → ROOT leaf path (populated by `register_particle`).
`meta_data`	`meta*`	Pointer to the dataset metadata object (set by `io` / `sampletracer`).
`filename`	`std::string`	Path of the ROOT file from which this event was read.
`data`	`event_t`	Raw event-level data struct (index, weight, hash, …).

Public Methods

Signature	Description
`template<G> void register_particle(std::map<std::string, G> object)`	Registers a particle collection: creates a prototype `G`, extracts its `type` and leaf map, and stores a pointer to object for population during `build_event`.
`template<G> void deregister_particle(std::map<std::string, G> object)`	Deletes and clears all entries in object. Call in the event destructor.
`void add_leaf(std::string key, std::string leaf = "")`	Adds an event-level ROOT leaf mapping (for event-level scalars, not per-particle).
`virtual void build(element_t* el)`	Called once per event entry. Override to create/populate particle maps from the ROOT branch data in el.
`virtual void CompileEvent()`	Called after `build`. Override to compute derived quantities (topology, secondary particles, truth matching).
`virtual event_template* clone()`	Returns a heap-allocated copy of this event. Override in subclasses. Caller owns the returned pointer.
`std::map<std::string, event_template> build_event(std::map<std::string, data_t>* evnt)`	Framework-internal: builds a map of fully populated event objects from the raw `data_t` map produced by `io`.
`std::vector<particle_template*> multi_neutrino(...)`	Runs the neutrino combinatorial solver for dilepton events. Parameters: targets (W-decay products), phi (MET φ), met (MET pt), optional mt (top mass, MeV), mw (W mass, MeV), violation, limit.
`bool operator == (event_template& p)`	Hash-equality comparison.
`void flush_particles()`	Frees all registered particle collections (called during cleanup).