CLEO Event Bookkeeping10/19/00 Jon J Thaler

Motivation:Maintaining relationships between elements of twosets of objects is a common analysis task.

Examples:Tracks hits. Event hypotheses Vertices tracks. kinematic entities.

Data analysis is the identification of increasingly complex relationships within the data.

Lattice

Documentation (almost up to date:)http://web.hep.uiuc.edu/home/jjt/Lattice/Lattice.html

CLEO Event Bookkeeping10/19/00 Jon J Thaler

The problem:Everyone “rolls his own” code.• Redundant.• Buggy.

Possible simplification:Manage this bookkeeping with a single shareable package. • Write and debug once.• Users can concentrate on analysis.

CLEO’s solution:Make object relationships an object (Lattice). Properties:• Addition and removal of connections between objects. • Association of data with each connection (“link data”).• Complete set of data access methods.

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Specifications:

• Flexibleº Any two sets of data can be connected.º Link data is user definable.º Lattices don’t interact.

Objects can belong to multiple Lattices.

• Minimal impact on existing code.º No performance penalty.º Little rewriting of working code:

Data must have an Identifier type. (CLEO data already had this.)

Gives type safety (LeftID ≠ RightID, usually).

CLEO Event Bookkeeping10/19/00 Jon J Thaler

The goal:• Establish and maintain connections between lists of data.

• Links hold information that describes the connection.

• Retrieve data in easy to use format.

• Specify connectivity constraints.

ID = 12

M

.

.

.

ID = 12

N

.

.

.

Links Right nodesLeft nodes

Lattice

User data User data

User data

User data

User data

.

.

. IDs do not need to be int

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Examples

Tracks Hits

2

1

2

3

1

8

2

Many One One Many

Track finding with hit sharing allowed

Notallowed

Clustering with classes of cluster membership.Overlaps allowed.

Clusters Hits

1

2

1

8

2

Many Many Many One

class 1

class 2

class 1

Clustering with classes of cluster membership.No overlaps allowed.

Hits

1

2

1

8

2

Many One Many One

class 1

class 2

class 1

class 2

Clusters

Track finding with hit sharing not allowed

Tracks Hits

2

1

2

3

1

8

2

Many One One One

Numbering is arbitrary.Lines might cross.

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Issues:• Simple interface.

Users only want to see one kind of container (STL vectors).

• Unobtrusive.Impose no functional requirements on data classes, so new Lattices can be added without requiring code modification or affecting program behavior.

• Persistence over write/read cycle.Lattice uses identifiers, not pointers to data.

• Performance.Optimized for data access, at the expense of slower data insertion. This is hidden from the user; could be modified.

• Adaptability.Generic implementation. A CLEO specific interface (i.e., to our data structures) is achieved by inheritance.

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Construction and remodeling:Construct: (It’s a class template, so some instantiation is required.)

pLattice = new Lattice<LeftData,RightData,LinkData>(Connectivity);

You specify data types, link data, and the allowed connectivity.

Remodel: (null pointer returned on failure)

Make a new link: (your LinkData will be copied to it)

Link* pLink = pLattice->connect(LeftID, RightID, LinkData&);

Connect data through an existing link:Link* pLink = pLattice->connect(LeftID, Link&, RightID);

Add datum to an existing link: Link* pLink = connect(Link&, RightID);

You are responsible for maintaining LinkData

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Data access functions:const vector<LeftID>* vLeft = pLattice->vLeftGivenLeft (LeftID);const vector<RightID>* vRight = pLattice->vRightGivenLeft(LeftID); const vector<Link*>* pLinks = linksGivenLeft(LeftID); const vector<LeftID>& vLeftID = pLink->vLeftID(); void connectLinks (LeftID, RightID, vector<Link*>&);void shareLinksLeft(LeftID, LeftID, vector<Link*>&);

Verbose nomenclature - I don’t know that LeftID and RightID are different types.

Too expensive to maintain.You supply vector; I fill it.

LinkData& ld = pLink->linkData();Gives you write access to a link’s data.

linksGivenLeft

connectLinks shareLinksLeft

vLeftGivenLeft vRightGivenLeft

vLeftID

“It’s your data.” (GWB)

CLEO Event Bookkeeping10/19/00 Jon J Thaler

Status:

• An integral part of the CLEO software environmentfor nearly two years (stable code, except when I “fix” something).

• Being adapted (or considered) by two other experiments.

• Not “plug and play,” but close.