Transcript presentation

SEAL: Common Core Libraries and
Services for LHC Applications
CHEP’03, March 24-28, 2003
La Jolla, California
J. Generowicz/CERN, M. Marino/LBNL,
P. Mato/CERN, L. Moneta/CERN, S. Roiser/CERN,
L. Tuura/Northeastern U.
Contents
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History: The blueprint RTAG
Project Aims
Current Work Areas:
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Foundation Libraries
Math Libraries
Plugin Management
LCG Dictionary
Scripting services
Project Status
Summary
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The Blueprint RTAG
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The mandate of the RTAG was to define the architectural ‘blueprint’
for LCG applications:
– Define the main architectural domains (‘collaborating frameworks’) of LHC
experiments and identify their principal components.
– Define the architectural relationships between these ‘frameworks’ and
components, including Grid aspects, identify the main requirements for
their inter-communication, and suggest possible first implementations.
– Identify the high-level milestones for each domain and provide a first
estimate of the effort needed.
– Derive a set of requirements for the LCG
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Any piece of software developed by any LCG common project must
conform to a coherent overall architectural vision
The end goal is the integration of LCG and non-LCG software to build
coherent applications
The blueprint will be established in terms of a set of requirements,
suggested approaches and guidelines, and recommendations
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Architecture requirements
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Long lifetime: technology evolution
Languages: C++ today; allow multi-language and evolution
Distributed applications
TGV and airplane work
Modularity of components
Component communication via public interfaces
Interchangeability of implementations
Integration into coherent framework
Design for end-user’s convenience more than the developer’s
Re-use existing implementations
Software quality at least as good as any LHC experiment
Meet performance, quality requirements of trigger/DAQ software
Platforms
Trigger/DAQ environment
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Architectural Elements
Interface model
– Abstract interfaces, versioning,
guidelines,…
Component model
Design guidelines
– Dependencies
– Exception handling
– Interface to external components
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Other
Frameworks
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Applications
Visualization
Framework
– Communication via public interfaces (no
hidden channels)
– Plug-ins (run-time loading)
– Live-time management (reference
counting)
– Configuration
Simulation
Framework
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Software Structure
Reconstruction
Framework
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Basic Framework
Foundation
Libraries
Optional Libraries
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Architectural Elements (2)
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Object Dictionary
– The ability to query a class about its internal structure
(Introspection)
– Essential for data browsing, rapid prototyping, persistency, etc.
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Object Whiteboard
– Uniform access to
application-defined
objects (equivalent to
the Gaudi transient
stores)
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EDG API
PVSS
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Database
Python
JPE
PyROOT
PyGaudi
Java
Classes
Root
Classes
Gaudi
Frame
work
Component Bus
– Integration of components
providing a wide variety
of functionality
XML
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math
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GUI
GUI
shell
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The Blueprint RTAG Recommendations
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RTAG establishes a user/provider relationship between
LCG software an ROOT
– LGC software will not be based on ROOT, it will use ROOT where
adequate
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Start common project on core tools and services
 SEAL Project
Start common project on physics interfaces
Start RTAG on analysis, including distributed aspects
Tool/technology recommendations
– CLHEP, CINT, Python, Qt, AIDA, …
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Develop a clear process for adopting third party software
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SEAL Overview
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SEAL aims to
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Provide the software infrastructure, basic frameworks, libraries
and tools that are common among the LHC experiments
Select, integrate, develop and support foundation and utility class
libraries
Develop a coherent set of basic framework services to facilitate
the integration of LCG and non - LCG software
Scope
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Foundation Class Libraries
» Basic types (STL, Boost, CLHEP, …), utility libraries, system
isolation libraries, domain specific foundation libraries
Basic Framework Services
» Component model, reflection, plugin management, incident
(event) management, distributed computing, grid, scripting
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Domain Coverage
EvtGen
Algorithms
Engine
Event
Generation
Fitter
Detector
Simulation
Scripting
NTuple
Reconstruction
GUI
Analysis
Interactive
Services
Modeler
Geometry
Calibration
Event Model
FileCatalog
StoreMgr
Dictionary
Whiteboard
Persistency
Scheduler
PluginMgr
Core Services
Monitor
Grid
Services
Foundation and Utility Libraries
ROOT
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GEANT4
FLUKA
MySQL
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DataGrid
Python
Qt
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Assumptions, constraints, risks
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Do not re-invent wheel
– Most of the core software to be delivered by SEAL exists - more
or less - in experiments’ core software
» We will re-use as much as possible existing software
» Most of the work will be in re- packaging existing pieces of
software
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If wheel squeaks…
– Develop / adapt / generalize in order to achieve the necessary
level of coherency and conformance to the architectural vision
already established
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Adopt a Seal
– In order to use SEAL, projects will need to replace their own
software elements with SEAL functionally equivalent ones. This will
certainly imply some period of instability for the experiment
applications
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Work Packages
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Foundation and Utility Libraries
Math Libraries
Component Model and Plug-in Manager
LCG Object Dictionary
Basic Framework Services
Scripting Services
Grid Services
Education and Documentation
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Foundation and Utility Libraries
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Low level, fairly independent class libraries complementary
to Boost and STL from existing code in classLib (CMS),
Gaudi (ATLAS/LHCb), HepUtilities, etc.
Broad range of unrelated functionalities which makes
sense to re-use across LCG projects
Developed or adapted as the need arises
– Inventory of existing utility classes
» http://cern.ch/seal/components.html
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Current Status
– Release 0.1.1 provides few classes used by POOL
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Math Libraries
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The Math Libraries project (F. James et al.) is becoming a
work package of the SEAL project. Started to define the
work plan
Provides experiments with math and statistics libraries to
be used in analysis, reconstruction, simulation.
Current activities
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Evaluation of GSL (India). To be finished by 15 April 2003
Implementation of Minuit in C++
CLHEP participation and support
GSL support
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Component Model and Plug-in Manager
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In the LCG architecture a plug-in is a logical module that encapsulates
the concrete implementation of a given service.
The plug-in manager is responsible for loading, activating, deactivating
and unloading plug-ins at run-time
Current activities
– Develop/adapt a basic set of mechanisms and base classes to manage
creation of objects (factories), lifetime, multiplicity and scope, component
communication and interface discovery
– Ideas and code re-use from Iguana (CMS) and Gaudi (LHCb/ATLAS).
Plug-in
Database
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Plug-In
Plug-In
Cache
Plug-In
Cache
Cache
Module
Module
Module
Module
Module
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Object
Object
Factory
Factory
Attached
Unattached
Object
Factory
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LCG Object Dictionary
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Areas of work
– Reflection Packages (Reflection, ReflectionBuilder)
– Dictionary generation from header files using gcc_xml technology
(DictionaryGenerator)
– Python-binding to Reflection
– Gateway CINT -> LCG Dictionary
– Generation of .h files and dictionary from higher level language
(e.g. XML)
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Concentrating in Reflection packages and dictionary
generation from header files
– Main goal: Full support of C++ without any class instrumentation
– Parsing XML file from gccxml and producing “usable” dictionaries
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LCG Object Dictionary: Usage
.adl
.xml
.h
Population
ROOTCINT
GCC-XML
CINT generated
code
Dict generating
code
ROOT I/O
in
(1)
CINT
Dict
LCG to CINT
Dict gateway
Conversion
Streamer
ADL/GOD
LCG
Dictionary
(2)
out
Other
Clients:
(python,
GUI, etc.)
Reflection
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Dictionary generation from header files
.xml
.xml
.h
gccxml
.h
.h
.h
(python script)
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par
ser
selection file
filter gendict
+
exten
_dict.cpp
make
.so
lcgdict
#include files
Uses gccxml (0.4.1) to parse header-files (extension to gcccompiler), generates intermediate XML file with dictionary
information
XML file parsed by a python script which generates dictionary
building C++ code (for “selected classes”)
Compiled to shared library and loaded at run-time to create
dictionary in memory
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Framework Basic Services
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Develop a set of basic services to be used by LCG
applications for message reporting, exception handling,
component configuration, “event” management, etc.
– Starting with the most basic ones
– Extended later with potentially common services identified in other
projects
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Framework level base classes and interfaces
– Provide a number of base classes to facilitate the task of building
applications
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Develop object “whiteboard”
– Access to application-defined objects (event data objects, for
example) will be supported throughout the system.
– Study interaction with persistency, visualization and other services
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Scripting Services
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The Blueprint RTAG proposes interoperability between
ROOTCINT and Python
– Possibility to access application-defined objects from both of
these environments
– Python bindings for ROOT (PyROOT)
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Python bindings to standard services and utility libraries
developed in SEAL
Current activities
– Evaluate existing Python binding options: SWIG, Boost.Python, SIP,
raw Python API, etc.
– Started with PyROOT (C++) and PyGSL (C) as examples in the
evaluation process. They are candidates to become “real” products
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Project Status and Summary
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The SEAL project started last November
– To provide the software infrastructure, basic frameworks, libraries and
tools that are common among the LCG projects and LHC experiments
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First pre-release (v0.1) end of February
– Various packages: SealKernel, Reflection, ReflectionBuilder,
DictionaryGenerator
– Used by POOL release v0.4
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Second pre-release (v0.2) expected in 1 week
– Evolution of the existing packages and additional ones: SealSystem,
PyROOT, …
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First complete release (v1.0) scheduled end of June
– Sufficient functionality to be used by other LCG projects and LHC
experiment’s Frameworks
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For more information: http://cern.ch/seal
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