GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, AIDA Abstract Interfaces for Data Analysis Andreas Pfeiffer CERN IT/API

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 2 Outline What is AIDA History/Collaboration/Documentation Some Details Examples Ongoing work Summary

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 3 What is AIDA Abstract Interfaces for Data Analysis (AIDA) “The goals of the AIDA project are to define abstract interfaces for common physics analysis objects, such as histograms, ntuples, fitters, IO etc.The adoption of these interfaces should make it easier for developers and users to select to use different tools without having to learn new interfaces or change their code. In addition it should be possible to exchange data (objects) between AIDA compliant applications.”

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 4 Motivation Advantages The user needs to learn only one set of interfaces Same user code can be used with different AIDA-compliant analysis applications Pool experience of different developer teams LHC++, OpenScientist, JAS Different analysis tools can exchange analysis objects same storage format, use functionality from other tools Two versions of AIDA interfaces One for C++ One for Java As identical as possible

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 5 Abstract Interfaces only pure virtual methods, inheritance only from other A.I. components use other components only through their A.I. defines a kind of a “protocol” for a component Maximize flexibility and re-use of packages allow each component to develop independently re-use of existing packages to implement components reduces start-up time significantly De-couple implementation of a package from its use

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 6 AIDA Example Use same code with any AIDA-compliant analysis tool. AIDAAIDA User code (e.g. GEANT4) Analysis tool 1 Analysis tool 2

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 7 Architectural issue: Components (I) Identify components by functionality Define “protocol” using Abstract Interfaces Emphasize separation of different aspects for each component Example: Histogram statistical entity (density distribution of a physics quantity) view of a “collection of data points” (which can be a density distribution but also a detector efficiency curve) command to manipulate/store/plot/fit/... “User’s view” is different from “implementor’s (developer’s) view” separate Abstract Interfaces for both aspects

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 8 Use of Components with Abstract Interfaces User Code uses only Interface classes IHistogram1D * hist = histoFactory-> create1D(‘track quality’, 100, 0., 10.) Actual implementations are selected at run-time loading of shared libraries No change at all to user code but keep freedom to choose implementation Histo- Impl. 2 Histo-IFFitter-IF User Code Fitter- Impl. Y Histo- Impl. 1 Fitter- Impl. X

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 9 Across the languages JAida : C++ access to Java libs using C++ proxies implementing the C++ Abstract Interfaces to the Java interfaces C++UserCode AIDA-IF C++AIDA-IF Java Java Lib JAida

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 10 XML standards Started with 1D and 2D Histograms aim: easy transfer between applications Will extend to other data types other histos, fits, ntuples, … Comments/contributions welcome !

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 11 History Initial idea formed during discussion at HepVis-99 workshop at Orsay Informal AIDA discussions at CERN in 2000 AIDA workshops: January Paris/Orsay April Boston (preceding HepVis 2001) Informal meetings (e.g during Geant4 meetings and video conferences) June 2002 – CERN Interfaces have been designed by discussion and (eventual) consensus Takes some time, but result is well though out and robust

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 12 Organization - Developers No formal collaboration/author list. Some people who have contributed (ideas, code, etc). Guy Barrand, Pavel Binko, Mark Donszelmann, Wolfgang Hoschek, Tony Johnson, Emmanuel Medernach, Dino Ferrero Merlino, Lorenzo Moneta, Jakub Moscicki, Ioannis Papadopoulos, Andreas Pfeiffer, Max Sang, Victor Serbo, Max Turri Apologies to people accidentally missed

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 13 Organization – Code, Documentation AIDA – open source project CVS repository: cvs.freehep.org “anonymous” download available Web page: General information, relevant links Tutorial, users’ guide, examples Downloads and web-browsable source code Test cases (coming soon)

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 14 Current Status AIDA Version 2.2 released (December 2001) First “End User” release Three implementations of AIDA exist Anaphe/Lizard (C++) Open Scientist (C++) JAIDA/JAS (Java) + AIDA-JNI 1.0 (C++) GEANT4 adopted AIDA for analysis AIDA 3 Currently under discussion Release foreseen for Sep 2002

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 15 AIDA Interfaces Summary AIDA Factories ITuple IHistogram ICloud ITree

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 16 AIDA Design

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 17 Aida design (details) File: /data/pfeiffer/Rose/AIDA-2.2.mdl Sun Jun 30 17:18: Class Diagram: Logical View / Main Page 1

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 18 Example Program (Java) Create, fill, and view 1D and 2D histograms:

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 19 ITuple ITuple - interface to the Data “get/set” methods for double, float, int, … Information about columns: min, max, mean, rms Navigating: start(), next(), skip(int nRows) Project ITuple into 1D, 2D, 3D histogram New features for AIDA 2.3: Support for complex internal structures (subfolders) Merging and chaining of ITuples under discussion

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 20 Details - ITuple Interface to the Data:

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 21 IHistogram (1D-3D) Binned histogram: IHistogram1D, 2D, 3D “fill” methods (with/without weight) Histogram info: entries, mean, rms, axis Bin info: centre, entries, height, error Histogram arithmetic: add, multiply, divide Convenience methods, like coordinate-to-index conversion

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 22 Details – IHistogram (1D-3D) IHistogram: Common functionality for all histograms (like entries, label, dimension,) IHistogram1D IHistogram2D IHistogram3D

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 23 ICloud Unbinned collection of points: ICloud1D, 2D, 3D Can represent scatter plot, dynamically rebinnable histogram Can be converted to a binned histogram Standard “get/set” methods for entries Collection info: lower, upper, mean, rms

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 24 Details - ICloud ICloud: Common functionality for all histograms (like entries, label, dimension,) ICloud1D ICloud2D ICloud3D

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 25 IFunction and Fitting Fitting: IFunction, IFitFunction IFunction – simple interface, allows to set parameters and get function value IFitFunction – fit function to a histogram Extends IFunction Various fit control methods: step size, bounds, etc. Allows to perform fit and get results AIDA 2.2 fitting functionality fairly limited AIDA 2.3 (Under discussion) extended functionality

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 26 ITree directory-like structure (Unix directory convention) Methods like: cd, ls, mkdir, etc. AIDA analysis objects (tuples, histograms, clouds, ets.) exist within ITree directories “save/restore” functionality, hides storage details from the user Compatible with database or file storage Can support multiple file formats Mount/Unmount functionality (like unix) allows multiple stores to be seamlessly merged AIDA XML format is defined for data interchange

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 27 Details - ITree Directory-like structures: ITree

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 28 June 2002 Developers Workshop 2 Day “Users Workshop” 3 Day “Developer Workshop” Items under discussion Fitting (two proposals, from SLAC, CERN) Similar but different, differences need to be resolved Improved plotting (IPlotter) Graph (XYData) Tuple chaining, merging Small updates/extensions to API Input/Participation from people always welcome !

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 29 Ongoing work Refining Fitter and Plotter components IFitter, IOptimizer, IFitResult Iplotter, I*Styles for plotting Developer-level interfaces Code sharing More robust operation Put AIDA-based utilities in CVS Utility to test AIDA implementations User contributions Common binary storage format

GranSasso, Jul-2002 Andreas Pfeiffer, CERN/IT-API, 30 Summary Abstract Interfaces de-couple components of frameworks Weakly coupled components and frameworks have large advantages User code needs no change if changing implementation Even across “language boundaries” (JAIDA) Ease of re-use of a component Flexibility through independence of implementation Maintainability through independent evolution of components Example using Geant-4 and AIDA compliant analysis tools (see tutorial)