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The D0 Monte Carlo Challenge
Gregory E. Graham
University of Maryland
(for the D0 Collaboration)
February 8, 2000 CHEP 2000
February 8, 2000 Greg Graham - CHEP 2000 2
D0 Monte Carlo Challenge Goals
• Testing the D0 GEANT Monte Carlo Program (D0GSTAR)
– Performance : CPU time, event size, memory
– Accuracy of detector simulation
• Testing the D0 Reconstruction Program (D0RECO)
– Performance : CPU time, event size, memory
– Efficiency and rejection power of reconstruction algorithms
February 8, 2000 Greg Graham - CHEP 2000 3
D0 Monte Carlo Challenge Goals
• Testing the infrastructure for running D0GSTAR and D0RECO
– remote site Monte Carlo generation
– storage testing (Sequential Access Method - SAM) (C241 - these proceedings)
– farm processing (E60 - these proceedings)
• Testing the integration of these systems with large numbers of events
– Stress testing
February 8, 2000 Greg Graham - CHEP 2000 4
D0 Monte Carlo Challenge Goals
• Evaluating the Physics Potential of the D0 Detector in Fermilab Tevatron Run II– detailed studies of different physics processes
– trigger studies
– algorithm performance
– background rejection / signal efficiency
– discovery potential
February 8, 2000 Greg Graham - CHEP 2000 5
The D0GSTAR Program
• Based on GEANT 3.21 (Fortran) with C++ wrapper– Linux and IRIX Platforms
• Input is ISAJET, PYTHIA (with QQ libraries and TAUOLA )
• Output are Hits and Digi information• Typical event size : 1.0 - 1.5 MB• Typical detector simulation time : 5 - 7 minutes
– Shown for SGI R12000 processor at 300 MHz
February 8, 2000 Greg Graham - CHEP 2000 6
D0 Monte Carlo Challenge Objectives
• Phase I : Initial Stage (Summer 1999)
– Generate 100,000 events
– Test and develop D0GSTAR, D0RECO
• Phase II : Intermediate Stage (Winter 2000)
– Generate 300,000 - 500,000 events
– Use remote sites for MC generation– Further testing and development of D0GSTAR, D0RECO
– Integration of Systems
– Initial Physics and Trigger studies
February 8, 2000 Greg Graham - CHEP 2000 7
D0 Monte Carlo Challenge Objectives
• Phase III : Final Stage (Fall 2000)– Further develop remote MC generation sites– Further testing of software systems integration– Trigger studies – Physics Studies– Double Blind tests
February 8, 2000 Greg Graham - CHEP 2000 8
D0 Monte Carlo Challenge Phase II
• How do we efficiently generate 500,000 D0GSTAR MC events ?
– This corresponds to about 55,000 CPU hours (on a 300 MHz/CPU)
• How do we store 500,000 MC events ?
– This corresponds to about 0.6 TB of data• How do we further improve our capacity for MC generation
while ensuring homogeneity of generated samples at remote sites ?
February 8, 2000 Greg Graham - CHEP 2000 9
MCC Event Generation and Storage
• Use many remote computing facilities to generate Monte Carlo– MC generation must be homogenized– Tools to collect statistics on MC generation
• Use SAM / ENSTORE system at FNAL to store event files– Currently configured to use a tape robot using
Mammoth-I tapes (18 GB/tape)
February 8, 2000 Greg Graham - CHEP 2000 10
MCC Remote Processing Sites
SAM
FNA L -M CC L yon N IK HE F P rag u e UTA O th ers ...
FNA L
February 8, 2000 Greg Graham - CHEP 2000 11
MCC Remote Processing Sites
• FNAL (Batavia, IL)– 17 processors on 48 processor SGI R12000
– 300 MHz, memory 250 MB/processor
• Lyon (IN2P3,France) – 15 dual Pentium II/III PC Farm
– 450/500 MHz, memory 250 MB/processor
• Amsterdam ( NIKHEF, Netherlands )– 6/128 processors on 128 processor SGI R10000 (now
32/128 - Thanks, Kors!)
– 250 MHz, memory 450 MB/processor
February 8, 2000 Greg Graham - CHEP 2000 12
MCC Remote Processing Sites• Prague (Czech Rep. Acad. Sciences)
– 3 Pentium III based PCs
– 450/500 MHz, memory 128/256 MB/processor
• University of Texas at Arlington– 7 dual Pentium III PCs
– 500 MHz, memory 250 MB/processor
• Further Sites in the Planning Stage– Lancaster (UK), Nijmegen, and others
– Hardware upgrades are also being planned
February 8, 2000 Greg Graham - CHEP 2000 13
MC Homogeneity• Event Generation is by isajet or pythia
– these are D0 standard tools (cvs package)– supplemented by QQ and tauola
• D0GSTAR is also standard– D0GSTAR based on 3 cvs packages– Linux and Irix platforms
• Python based tools for MC generation– Standardized input files– Random number seeds updated
automatically– Built in scripting tool for multi-job
generation
• No D0 environment necessary– Distributed as executables + libraries + input
files + tools
February 8, 2000 Greg Graham - CHEP 2000 14
Collecting the MC Data
• After generation, MC data is imported into SAM– Directly into SAM via sam store commands (possible
at FNAL site)
– Via ftp connection to SAM import site
– Via Mammoth-I tapes (plus suitcase and airplane ticket)
• Statistics for generation are now collected locally at the remote sites and compiled by hand at the central site
February 8, 2000 Greg Graham - CHEP 2000 15
Results on Generated Events
QCD DIJET events in each of 7 different Et thresholds . . . . 50K tt events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50Kb J/(ee or). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50K Z ee, , each . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10KZ bb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5KW eeach) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1K jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1K ee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1K Other Signal Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10K
Total Generated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500K
And we still continue to generate events !
Snapshot January, 2000
February 8, 2000 Greg Graham - CHEP 2000 16
Results on Generated Events
MCC production by site
FNAL . . . . . . . . . . . . . . . . . . . . . 240KLyon . . . . . . . . . . . . . . . . . . . . . . 210KNIKHEF . . . . . . . . . . . . . . . . . . . 30KPrague . . . . . . . . . . . . . . . . . . . . . 20KUTA . . . . . . . . . . . . . . . . . . . .(just starting)
Total . . . . . . . . . . . . . . . . . . . . . . 500K
Snapshot January, 2000
February 8, 2000 Greg Graham - CHEP 2000 17
MCC Event Generation Capacity• Generation Capacity
– Phase II has achieved a capacity of about 5,000 events per day at all existing remote sites
– Can expand to at least 25,000 events per day with further hardware upgrades and new centers
• Storage Capacity– Network bandwidth less than desirable (ftp), but not a
bottleneck
– 0.6 TB stored so far in SAM, also not a bottleneck
February 8, 2000 Greg Graham - CHEP 2000 18
MCC - Debugging D0• Integration issues are being addressed
– SAM was exercised extensively. Problems were uncovered and debugged in the software.
• Debugging D0RECO– Six pass minor releases in current production release
• Development of tools– micro-DST, Analyze tools
• Problems were uncovered and fixed in the MC generation tools at remote sites
• Beginning to look at D0TRIGSIM, uDSTs, etc
February 8, 2000 Greg Graham - CHEP 2000 19
What Did We Learn• Every remote site is different
– porting and verifying released code was easy– porting the MC generation tools was hard
• Python/Tk
• UNIX shells
• Customization
• Compiling statistics by hand is hard– we need a tool to do this
February 8, 2000 Greg Graham - CHEP 2000 20
Future Plans for MCC Phase III
• Develop tools to better control remote production– Presently, remote production is controlled locally
– Software is being developed to control MC generation over the network from a central server
• Develop tools to collect MC generation statistics– Software is being developed to automate collection of
MC generation statistics
February 8, 2000 Greg Graham - CHEP 2000 21
Conclusions• Integration of D0 MC production, storage, and access
was extensively tested (and debugged!) – 500 K Events generated for D0 Experiment
– 55,000 distributed CPU hours logged since 10/1/99 at 5 remote sites
– 0.6 TB of data successfully stored on SAM
• Certification of the D0RECO program is currently underway using the MCC samples
• Other projects (eg- trigger simulation) are ramping up