The `Event` class

The Event class is nothing more than a collection of containers

Event class layout
Container type	Name	Description
Header	header	Contains simple information like run number, run tag, event number and UTC time.
EventSummary	evSummary	Contains some aggregated variables to roughly describe the event.
DAQ	daq	Contains variables describing the status of the AMS DAQ system for the event.
TofBase	tofBase	Contains basic Tof variables that are accessed most frequently
TofPlus	tofPlus	Contains additional Tof variables that are accessed less frequently
TofBaseStandalone	tofBaseSt	Contains basic Tof variables that are accessed most frequently (no-tracker reconstruction)
TofPlusStandalone	tofPlusSt	Contains additional Tof variables that are accessed less frequently (no-tracker reconstruction)
EcalBase	ecalBase	Contains basic Ecal variables that are accessed most frequently
EcalPlus	ecalPlus	Contains additional Ecal variables that are accessed less frequently
TrTrackBase	trTrackBase	Contains basic Track variables that are accessed most frequently
TrTrackPlus	trTrackPlus	Contains additional Track variables that are accessed less frequently
TrdKBase	trdKBase	Contains basic TRD variables that are accessed most frequently
TrdKBaseStandalone	trdKBaseSt	Contains basic TRD variables that are accessed most frequently (no-tracker reconstruction)
RichBase	richBase	Contains basic RICH variables that are accessed most frequently
RichPlus	richPlus	Contains additional RICH variables that are accessed less frequently
UnbExtHitBase	extHitBase	Contains basic variables for unbiased external hits
MCTruthBase	mcTruthBase	Contains basic MC truth variables that are accessed most frequently
MCTruthPlus	mcTruthPlus	Contains additional MC truth variables that are accessed less frequently

The Event class acts as an interface to group and access containers with information from the various subdetectors. This should be provided by the chain class as a transient view of the event information.

Note

Containers are actually made up from two classes. The first one is the one holding all the variables, while the second one adds the “read-on-demand” behavior to the container.

When navigating the doxygen documentation remember to go check the XXXData class, where “XXX” is the container Class, and you’ll find the description for all the container variables.

The event `Category`

To avoid going through every event every single time you can perform a fast event filtering by looking at the event Category mask in the Header container.

Note

To check if an event belongs in a given set of categories you can use the Header::CheckMask method.

Categories can be combined into a single mask, to check many of them at once

// this mask will check for charge=1 according to both tracker and tof
NAIA::Category cat = NAIA::Category::Charge1_Trk | NAIA::Category::Charge1_Tof;

  for (NAIA::Event &event : chain) {
    // check charge with TOF and Tracker
    if (!event.header->CheckMask(cat))
      continue;

CheckMask will check that all categories are present in the event. If you want to perform the check in or rather than and you can use the MathAnyBit free function

// this mask will check for charge=1 according to both tracker or tof
NAIA::Category cat = NAIA::Category::Charge1_Trk | NAIA::Category::Charge1_Tof;

  for (NAIA::Event &event : chain) {
    // check charge with TOF or Tracker
    if (!NAIA::MatchAnyBit(event.header->Mask(), cat))
      continue;

(n.b: the CheckMask method uses the MatchAllBits free function)

The Event class

The event Category

The `Event` class

The event `Category`