1. CEDAR Combined E-science Data Analysis Resource http://www. cedar. ac
JetWeb
HepData
A collaborative project between UCL (London) and IPPP (Durham)
Funded by PPARC E-Science call in 2003 (independent of the IPPP) – basically providing funding for 2 RAs ( ).
Main purpose is to integrate and modernize: JetWeb (UCL) and HepData (Durham) to provide data archival and presentation with validation of MCs to experimental data.
Plus: development tools/environment : HepForge
Extra: CEDAR tools being used to tune MCs`
People involved:
UCL: James Monk, Jon Butterworth, Ben Waugh, Emily Nurse……
Durham: Andy Buckley, Mike Whalley, James Stirling
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2. Why do we need CEDAR/Problems?
Analysis of the complex events from LHC will require:
MC simulations to be precisely tuned and validated over the full kinematic range
JetWeb (UCL –developed at HERA)
allows validation of MCs against a wide range of experimental data.
‘number crunching’ part - HZTool – written in Fortran
contains individual routines for each data set/analysis,
but modern analyses and MCs use C++ !
HepData (Durham – Reaction database)
~30 year archive of published ‘cross section’ data
could directly provide the input real data to JetWeb
but its Data Base Management System is not suitable
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3. HepData upgrade Old HepData database - Hierarchical -DBMS – Fortran!.
(actually HDBMS suits the data well)
Most modern DBMS are Relational – eq MySQL,Oracle,…
New HepData version – to use MySQL
Features:
Handles data with a Java object model
Object-relational mapping via Hibernate(DB) and Castor(external HepML/XML).
New front-end via Java servlets/Tapestry.
Data plotting/export via (J)AIDA.
User input (more direct): HepML/Web Form – authentication?
Migration of old data is underway:
Hdbms <Fortran> flat files <Python> hepml <Castor/Java/Hibernate> New DB
Objects – paper,
datasets, axes, bins
points,errors, etc.
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4. New HepData Structure MySQL hibernate xml castor Java Java Servlets
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5. JetWeb upgrade distributions + comparisons with real data.
System for running MC generators + database of calculated
distributions + comparisons with real data.
Work on the upgrade primarily at UCL:
Replace HZTool/HZSteer
with Rivet/RivetGun
Interface with HepData and
the new Java data model
Modernize the front end web
interface
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6. JetWeb screenshots
OLD
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7. Hztool upgrade: Rivet/RivetGun Robust Independent Validation of Experiment and Theory
Rivet is essentially a C++ replacement for the Fortran HZTool.
Performs an analysis on a set of particles from a simulated collision.
Combination of tools, analysis handler and analyses.
Outputs histograms for comparison to data from HepData and for inclusion in JetWeb.
Release v0.9 on 29/6/2007
RivetGun interfaces Rivet to the MCs, thereby isolating the generator steering from Rivet and allowing selection of the parameters and running the Rivet analyses.
At present supports FHerwig, FPythia, AlpGen, Sherpa, Herwig++ and Pythia8.
$rivetgun-static –g FPythia –n 5000 –a HEPEX
-beam1 PROTON –mom1 980
-beam2 ANTIPROTON –mom2 980
-P fpythia.params –l RivetGun:WARN
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8. HepForge
Online development environment for free HEP projects (mainly for CEDAR, but supported)
For those who want to provide quality multi-use software for HEP.
HepForge provides the user with:
Subversion version control (SVN)
Trac issue tracker/wiki/SVN browser
Mailman mailing lists
Downloads management…..
We don’t provide large volume storage or CPU resources though!
Currently about 40 projects, 80 users.
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9. HepForge
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10. Tuning with Rivet (next step from CEDAR- Professor)
As so often happens, MC parameters are highly correlated, so no point in tuning one parameter at a time…
High-dimensional parameter space, n>~10
Data from LEP, RHIC, HERA, Tevatron.
Delphi tuning: fit MC results to quadratic in n variables:
Being reimplemented with Rivet machinery.
Andy Buckley + Hendrick Hoeth (Wuppertal) + Frank Krauss & Dresden group
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11. Tuning with Rivet
n-dimensional hypercube specifying sample ranges in each parameter
generate N random n-vectors in the hypercube
run RivetGun/Rivet on each set of vectors to produce N Rivet output files, each of which describes B bins.
for each bin b fit polynomial function to the N generated values, using SVD
Use real data from HepData to compute GoF such as
Minimise individual functions as:
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12. CEDAR - Summary
The HZTool C++ replacement, the Rivet/RivetGun system, now provides a unified mechanism to re-generate experimental analysis distributions with various MC generators.
HepData archive DBMS is being updated and is now used as the data source for Rivet and JetWeb.
JetWeb generates and archives Rivet distributions and compares with data from HepData through a user web interface.
HepForge accounts are available for suitable projects (current list include, Herwig++, Sherpa, LHAPDF… ~40 in total
Rivet will be combined with the Professor tuning system to automatically tune generators based on Rivet/Hepata mechanisms.
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