Test49: Geant4 Monte-Carlo Models Testing Tools
CERN Summer Student Project Report
PH-SFT Group, CERN
R. Atachiants (roman...
5 ADDITIONAL FEATURES
Figure 1: Output of the analysis tool
4 Universal DataBase for
Geant4 MC Models Testing
The second p...
7 CONCLUSIONS
5.3 Graphical User Interfaces
Figure 3: A graphical user interface for simulation
tool
Several graphical use...
REFERENCES REFERENCES
Figure 5: The post-simulation output of a simula-
tion of 10,000,000 events
to use API and graphical...
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Report: Test49 Geant4 Monte-Carlo Models Testing Tools

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Report: Test49 Geant4 Monte-Carlo Models Testing Tools

  1. 1. Test49: Geant4 Monte-Carlo Models Testing Tools CERN Summer Student Project Report PH-SFT Group, CERN R. Atachiants (roman.atachiants@gmail.com) Supervised by: M. Kosov (mikhail.kossov@cern.ch) August 25, 2009 1 Project Overview During the CERN Summer Student program, I worked in Geant4 team (PH-SFT). The project contained several different objectives: • a full conversion of all Test19 PAW-tests[3] of existing Geant4 [4] Monte Carlo models testing to ROOT environment [5] and creation of a fully automated testing system. • creation of a special DB (DataBase) for the ex- perimental data with an automatic process of comparison of the MC distributions with data. During the summer student work, the both objec- tives were accomplished and even more various im- provements has been made: auto-scaling features for the plots, graphical user interfaces for the tools, secondary nuclear fragments retrieval, etc. The cre- ated tools were designed with the flexibility and ease-of-use in mind. 2 PAW to ROOT Conversion Fist step of the project was to convert the several .kumac files counting approximately 3000 lines of code. Learning curve of the PAW and ROOT[1] environments was steeply, therefore the conversion was achieved in about 1 month. Few insights for the PAW to ROOT portin can be found on the CERN ROOT website (http://root.cern.ch/root/ HowtoConvertFromPAW.html), but it was rather insufficient for the big scale porting and mostly targeted the people who want to switch from PAW to ROOT. During the porting, experience shown that the C++ methods of ROOT are more comprehensive and therefore more verbose. First kumac macro conversion implementation showed 40% increase of the length of the simple macro port. 3 Simulation and Analysis After the conversion of all macro files to ROOT, three comprehensive tools were developed. • Experimental DB Creation Tool: a graph- ical tool has been developed for the creation of publication files (cf. 4) from ASCII data. Fig- ure 4 shows the GUI of this tool. • Simulation Tool: the goal of the tool is to take the publication file as the input and us- ing a Geant4 testing program (currently only Test19 executable) to perform a simulation on a Monte Carlo Model. The output of the test then transformed from ASCII files, cuts and rescaling for different secondaries are per- formed. The histogram data are then saved in the so-called simulation files for further analy- sis. The tool also produces a plot for the anal- ysis of the model on which the simulation was performed, as illustrated on figure 3. • Analysis Tool: the goal of the tool is to take several simulation files produced by the simu- lation tool and to draw the comparison graphs in order to compare different MC models in be- tween. The goal of the analysis is to compare the data points (spectra, experimental data) with the simulation curves. Figure 1 shows an example of the output of the tool. 1
  2. 2. 5 ADDITIONAL FEATURES Figure 1: Output of the analysis tool 4 Universal DataBase for Geant4 MC Models Testing The second part of my work at CERN was creating of a universal DB for Geant4 MC models testing. The created database consists of a collection of two types of elements: • Publication: contains an experimental data information, with the description a a function, cuts and secondaries. • Simulation: contains the simulated data (af- ter cuts) for a particular publication file. The publication and simulation files have exactly the same structure and are different only by seman- tics. The data is stored in ROOT files (TTrees) with headers in order to distinguish the items. Fig- ure 2 shows the structure of the c++ classes, cre- ated in order to represent the publication and simu- lation concepts. The header of G4TData class con- tains the projectile PDG code, target PDG code, argument (ex: T) and the MC model name which is only needed if the file is a simulation. The body of the G4TData contains a vector of G4TDataItem classes, which have the secondary fragment PDG code, cut variable (ex.: Θ, 45 degrees), the argu- ment (ex.: T) and the function (ex.: ∆S ∆E ). The records of the DB are organised in .root files, on the Linux file system, in particular the ext3 file system on Scientific Linux 5, which allows a sin- gle file of maximum 2TB. Ex-data (ASCII files) Figure 2: Representation of the Data and DataItem classes for both publications and simulations stor- age and manipulation. are in the test49/ascii directory and the publica- tions/simulations are in the test49/database direc- tory. 5 Additional Features 5.1 Automatic Scaling and Layout Management An auto-scale feature have been implemented in or- der to scale automatically the axis of plots, pro- duced by both analysis and simulation tools. The scale features supports logarithmic scaling of y-axis and linear scaling of x-axis. 5.2 Automatic Secondary Frag- ments Nuclear Mass Calcula- tions A feature for the nuclear mass calculation for secondary fragments have been implemented in the tools, the API is based on ROOT Geometry package, made by ALICE experiment, using the lastest data (NUBASE2003). August 25, 2009 2 R. Atachiants
  3. 3. 7 CONCLUSIONS 5.3 Graphical User Interfaces Figure 3: A graphical user interface for simulation tool Several graphical user interfaces have been made for the tools in order to give the possibility to use them in the simplest possible way. The GUIs have been built using ROOT widgets platform and therefore portable to different platforms (Mac OSX, Windows, Linux, ...). One can see on Figure 4 the GUI created in order to ease the use of creating publication files, and Fig- ure 3 shows a GUI for the simulation tool, where one can simply select the publication file and run the MC simulation. 5.4 Documentation and ROOT Con- tributions An extensive amount of documentation for the tool have been written, a simple User Guide can be found in the Geant4 Hadronics Wiki [2] . This User Guide shows how to get started and work with both simulation and analysis tools, and create publica- tion data files from ASCII files (both using ROOT macros or available GUIs). A contribution to ROOT also have been made, sev- eral bugs have been found during the work, submit- ted to ROOT team of PH-SFT and their correction have been initiated. Figure 4: A graphical user interface for making publication files from ASCII files 6 Results One of the main goals of the project was the PAW to ROOT conversion. The goal of this conversion were mainly to be able to run the simulations and process (analyse) bigger statistics than in old sys- tem. In order to prove that the system can han- dle big statistics, a Monte Carlo simulation using BERTINI MC Model was performed. This simula- tion produced 10,000,000 events, 52,508,486 entries and the output file of about 7.5 GB (Figure 5). 7 Conclusions In this paper my contribution to Geant4 testing fa- cility has been discussed. It has been proven that old PAW .kumac files can be completely ported to the ROOT platform and exactly the same result can be achieved. It has also been shown that the created simulation tool can produce practically un- limited results, in order of 2 TB statistics, limited purely by the file system. The simulation and anal- ysis tools that have been created also have been designed with the extensibility and ease-of-use in mind. The extensibility is achieved by using the abstract classes, data access layers and wrappers. The ease-of-use is achieved by building a very easy August 25, 2009 3 R. Atachiants
  4. 4. REFERENCES REFERENCES Figure 5: The post-simulation output of a simula- tion of 10,000,000 events to use API and graphical user interfaces. The experimental DB and different tools are implemented in ROOT classes, compiled in libG4ModelTester.so extension library for ROOT and placed in tests/test49 directory of Geant4 test- ing facility. References [1] The ROOT Users Guide. CERN, 2006. [2] R. Atachiants. http://geant4hadronics.wikispaces.com/ geant4+test49+documentation. Geant4 Test19 Documentation. [3] CERN. http://wwwasd.web.cern.ch/wwwasd/paw. PAW − Physics Analysis Workstation. [4] CERN. http://www.geant4.org/geant4. Geant4 Website. [5] Rademakers F. Introduction to root. CERN Summer Student Lecture. August 25, 2009 4 R. Atachiants

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