1. Vincenzo Innocente CERN/EP/CMC
CARF
an Analysis&Reconstruction Framework for CMS
Vincenzo Innocente
CERN/EP/CMC

2. CARF Development Philosophy
Tailored to CMS analysis and reconstruction
Serves present ORCA applications
priorities driven development
backward compatibility, legacy code and data!
Bottom-up (concreteabstract) development in synergy with other sub-systems
It is also a prototype of 2005 software
offers more than one solution to a single problem
NOT a generic “one size fit all” application framework
15 November 2018
Vincenzo Innocente CARF Fundamentals

3. CARF layered Structure
Core mechanisms
and “data structures” G3
Generic
Application
TestBeam H2
T9/X5
Raw
Data
Raw
Data
Raw
Data
Generic Clients
15 November 2018
Vincenzo Innocente CARF Fundamentals

4. Framework Basic Dynamics
No central ordering of actions, no explicit control of data flow: only implicit dependencies
External dependencies managed through an Event Driven Notification to “subscribers”
Internal dependencies through an Action on Demand mechanism
15 November 2018
Vincenzo Innocente CARF Fundamentals

5. Framework Main Services
Define the events to be dispatched and links them to the their actual source
Allow the selection among available resources (user plug-in’s)
Manage the “not yet removed” sequential components
15 November 2018
Vincenzo Innocente CARF Fundamentals

6. Framework Ancillary Services
User Interface
Error Report (Exception management)
Logging facilities
Timing facility (statistics gathering)
Utility library
Notably Objy utilities, wrappers and generic persistent capable classes
15 November 2018
Vincenzo Innocente CARF Fundamentals

7. Framework middle layer
A CARF Application is characterized by the events it dispatches
Implementation of generic clients to specific services (events)
simplified API
uniform detailed design
uniform use of ancillary services
Requires synergy with detectors’ sub-systems
15 November 2018
Vincenzo Innocente CARF Fundamentals

8. L1 Trigger Simulation Track Reconstruction “Physics” reconstruction
Use Cases
L1 Trigger Simulation
Track Reconstruction
“Physics” reconstruction

9. Vincenzo Innocente CARF Fundamentals
L1 Trigger Simulation
detectors
Front-end
trigger logic
Local trigger
Global trigger
Final trigger decision
15 November 2018
Vincenzo Innocente CARF Fundamentals

10. Vincenzo Innocente CARF Fundamentals
L1 Trigger Simulation
Accurate simulation of real electronics
In the real experiment only “final decision data” are propagated forward
Also required
Monitoring of single trigger units
Comparison of L1 trigger w.r.t. full reconstruction
ability to simulate just a part of the system
“save” computing intensive intermediate results
15 November 2018
Vincenzo Innocente CARF Fundamentals

11. Vincenzo Innocente CARF Fundamentals
Track Reconstruction
For each “detector element”
there are local measurements
of trajectory state-vector
(just position or more complex)
Local measurements are affected
by the detector element state
(calibrations, alignments)
Pattern recognition “navigates”
in the detector to associate
local measurements into a track
15 November 2018
Vincenzo Innocente CARF Fundamentals

12. “Physics” reconstruction
4-vector-like objects are built out of trajectories and localized energy deposits
A wide range of PID, jet, vertex etc algorithms can be applied to produce others 4-vector-like objects
Access to the “original” detector data maybe required
15 November 2018
Vincenzo Innocente CARF Fundamentals

13. Reconstruction Sources
15 November 2018
Vincenzo Innocente CARF Fundamentals

14. Reconstruction Scenario
Reproduce “Detector Status” at the moment of the interaction:
front-end electronics signals (digis)
calibrations
alignments
Perform local reconstruction as a continuation of the front-end data reduction until objects “detachable” from the detectors are not obtained
Use these objects to perform physics reconstruction and analysis
15 November 2018
Vincenzo Innocente CARF Fundamentals

15. Vincenzo Innocente CARF Fundamentals
Components
Reconstruction Algorithms
Event Objects
Other services (detector objects, parameters, etc)
Legacy not-OO data (GEANT3)
15 November 2018
Vincenzo Innocente CARF Fundamentals

16. CARF Fundamentals (inside the black box)
Detector Components
Event Driven Notification
Action on Demand
Web site:
htttp;//nicewww.cern.ch/~innocent/cmsoo/carf1298.ppt

17. Vincenzo Innocente CARF Fundamentals
Detector Components
Sim Hit
Loader
Local
Geometry
Load simulated
hits from MC
Generates Digis
from SimHits
(or loads them
from db)
Global
Geometry
Digitizer
Detector
Element
Time
Dependent
Parameters
Reconstruct
measured trajectory
state-vector from Digis
Reconstructor
15 November 2018
Vincenzo Innocente CARF Fundamentals

18. Event Driven Notification
Dispatcher
Obs1
Obs2
Obs3
Obs4
Observers
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Vincenzo Innocente CARF Fundamentals

19. Active and Lazy Observers
Dispatcher
Lazy
Obs2
obsolete
Lazy
Obs2
Lazy
Obs2
uptodate
Obsis a user object or a reconstruction algorithm which uses
services of LazyObs1 (for instance a detector object) whose status
depend on the event itself.
In turn LazyObs1 depends on LazyObs2(for instance a calibration object)
whose status also depends on the event itself.
When a new event arrives LazyObs1 and 2 get notified and they change status to “obsolete” without taking any further action.
When Obs gets notified it starts computation and will ask LazyObjs1 for a service.
At This point LazyObs1 will find itself obsolete and will try to update its status. In doing so it will ask a service to LazyObjs2 which will in turn find itself obsolete and will perform the computation to update its status.
Once updated, LazyObj2 will serve LazyObj1 which will in turn update itself
and serve Obs
Any further service requested to LazyObj1 or 2 will find the object up-to-date and only the computation (if any) to fulfill the specific service will be performed with no further update of its status.
If there is no request for service for a given event the LazyObjs stay obsolete.
Obs
Lazy
Obs1
uptodate
Lazy
Obs1
Lazy
Obs1
obsolete
15 November 2018
Vincenzo Innocente CARF Fundamentals

20. Vincenzo Innocente CARF Fundamentals
Action “on Demand”
Rec Hits
Rec Hits
Rec Hits
Detector
Element
Hits
Event
Rec T1 T1
Analysis is a “user object” where tracks (T1 and T2) built by two different algorithms (RecT1 and RecT2) are compared.
Both T1s and T2s are reconstructed out of intermediate HITS built by a common RecHits algorithm.
For each new event Analysis is notified.
It instantiates an iterator over tracks T1 which will ask Event for the T1s.
Event will not find any T1 and will ask RecT1 to reconstruct them.
RecT1 will ask Hits to Event (instantiating an iterator).
Hits are not there and Event will ask RecHits to reconstruct them.
RecHits return Hits to Event which hands over them to RecT1 which reconstructs T1s, gives them to Event which hands over them to Analysis.
Analysis will then ask Event about T2.
T2 are not there and event ask RecT2 to reconstruct them.
RecT2 ask Event for Hits, which are there, and are immediately returned to it.
T2 get reconstructed and given to Event will will hands over to analysis which will finally perform the comparison. T2
Rec T2
Analysis
15 November 2018
Vincenzo Innocente CARF Fundamentals

21. “Events” currently dispatched
Start Xing G3
Geom
Ready to build new
G3 simulated event
SimPileUp
New pile-up event
ready in Zebra memory
SetUp
SimTrigger
New trigger event
ready in Zebra memory
SetUp Observers are Objects
which depend on geometry
G3Event
New event “ready”
to be analyzed
15 November 2018
Vincenzo Innocente CARF Fundamentals

22. Vincenzo Innocente CARF Fundamentals
“RecObj” Object Model
15 November 2018
Vincenzo Innocente CARF Fundamentals

23. Object identification
A Detector object collection is identified by:
object type (or super-type)
detector element it belongs to
implicitly belongs to the “current crossing”
Required the detector to be “in place” and “operational”
15 November 2018
Vincenzo Innocente CARF Fundamentals

24. Object identification
A RecObj collection is identified by:
object type (or super-type)
name of the Reconstructor (same as RecUnit)
event it belongs to
Does not require the RecUnit to be in place or operational
15 November 2018
Vincenzo Innocente CARF Fundamentals