1. The
DANA
Analysis Framework
David Lawrence Jlab
Jan. 19, 2006 .

2. DANA uses a factory model to deliver data “on demand”

3. Factories and Data Objects
Factory: Implements an algorithm to create one type of object using input from other type(s) of object(s).
Data Object:Object produced by a factory. It may have persistence through a file.

4. Factories are accessed via the type of data they produce
vector<const DCDCHit*> cdchits;
eventLoop->Get(cdchits);
for(int i=0; i<cdchits.size(); i++){
float x = cdchits[i]->x;
float y = cdchits[i]->y; }

5. Factory Tags
Two factories producing data of the same type may be distinguished via their “tag”s
Example:
One factory may provide a list of objects that is a subset of the objects produced by another factory.

6. Factory Tags vector<const DParticle*> particles;
vector<const DParticle*> kaons;
eventLoop->Get(particles);
eventLoop->Get(kaons, “Kaon”);

7. DEventProcessor
Programs are made by deriving from the DEventProcessor class
DEventProcessor defines a set of callback methods that are called at the appropriate times during the data processing

8. DEventProcessor Callback Methods
class DEventProcessor{
public: …
virtual derror_t init(void);
virtual derror_t brun(DEventLoop *eventLoop, int runnumber);
virtual derror_t evnt(DEventLoop *eventLoop, int eventnumber);
virtual derror_t erun(void);
virtual derror_t fini(void); }

9. Multi-threading
Multi-core processors are on the near horizon. To fully leverage the next generation of CPUs, processes must be multi-threaded
Data analysis is a natural application for multi-threading where events are dispatched to processing threads.

10. Threads

11. Multi-threaded Event Processing
GlueX Pattern Finding on 2.4GHz Quad Opteron
1 thread
2 threads
3 threads
4 threads
5 threads
20 threads
357 Hz
680 Hz
994 Hz
1348 Hz
1155 Hz
1087 Hz
177 Hz
346 Hz
512 Hz
663 Hz
632 Hz
584 Hz

12. DEventSource
Event sources inherit from DEventSource which defines the API for extracting data
This way, the framework is divorced from the specific file format
New file formats (or online sources) may be added by defining a new DEventSource-based class

13. Shared Objects
DANA supports shared objects for implementing factories and DEventSource objects
Factories and Event Sources obtained from shared objects are given precedence over statically linked ones.

14. Configuration Parameters
Parameters used to control the behavior of the algorithms (e.g. minimum number of hits per track)
Kept as key/value pairs in DApplication with standard way of setting and retrieving
NOT calibration constants

15. Configuration Parameters
A configuration parameter can be used as the factory “tag” (switchyard)
string TRACKHIT_SOURCE = "MC";
dparms.SetDefaultParameter("TRK:TRACKHIT_SOURCE", TRACKHIT_SOURCE);
loop->Get(trackhits, TRACKHIT_SOURCE.c_str());

16. Object Identifiers All Data Objects have a member:
identifier_t id (identifier_t is typedef’d as int)
Identifiers are used to reference one object from another in a way that can be stored and retrieved from a file.

17. Object Identifiers
vector<const DTrackCandidate*> trackcandidates;
vector<const DTrack*> tracks;
loop->Get(trackcandidates);
loop->Get(tracks);
for(unsigned int i=0;i<tracks.size();i++){
const DTrackCandidate *trackcandidate =
GetByID(trackcandidates, tracks[i]->candidateid); … }

18. Example main() routine
#include "MyProcessor.h"
#include "DApplication.h"
int main(int narg, char *argv[]) {
// Instantiate our event processor
MyProcessor myproc;
// Instantiate an event loop object
DApplication app(narg, argv);
// Run though all events, calling our event processor's methods
app.Run(&myproc, 4);
return 0; }

19. Nightly Generated DOxygen documentation