Differences

This shows you the differences between two versions of the page.

--- community:hepsim:dev_fast [2016/04/28 15:23]
asc
+++ community:hepsim:dev_fast [2016/07/18 14:29] (current)
asc
@@ Line 1: / Line 1: @@
 [[community:hepsim:|<< back to HepSim manual]]
-====== Creating fast detector simulations ======
 ===== Creating Delphes files  =====
@@ Line 14: / Line 14: @@
 Here are the steps to perform a  fast detector simulation using ProMC files from the HepSim repository:
-) Download [[http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.2.0.tar.gz | Delphes-3.2.0.tar.gz]] (or higher) and compile it as:
+) Download [[http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.3.0.tar.gz | Delphes-3.3.0.tar.gz]] (or higher) and compile it as:
 <code bash>
 wget http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.2.0.tar.gz
-tar -zvxf Delphes-3.2.0.tar.gz
+tar -zvxf Delphes-3.3.0.tar.gz
-cd Delphes-3.2.0
+cd Delphes-3.3.0
 ./configure
 make
@@ Line 43: / Line 43: @@
 </code>
 The conversion typically takes 30 seconds.
+===== On the fly reconstruction =====
+HepSim can be used to create ROOT (Delphes) files fast simulation program on the fly.
+The latter approach allows to make changes to  the detector geometry by the end-users and, at the the same time, perform an analysis.
+The output ROOT file only includes histograms defined by the user (but you can also add custom ROOT tree).
+To do this, use the [[http://atlaswww.hep.anl.gov/asc/hepsim/soft/FastHepSim.tgz| FastHepSim package]]
+that includes [[http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.2.0.tar.gz | Delphes-3.2.0]] and ProMC 1.5, as well as an example analysis program.
+You can find a description of the [[https://atlaswww.hep.anl.gov/asc/wikidoc/doku.php?id=vlhc:hcal|current HCAL studies]] that use such an approach.
+Follow these steps:
+<code bash>
+wget http://atlaswww.hep.anl.gov/asc/hepsim/soft/FastHepSim.tgz
+tar -zvxf FastHepSim.tgz
+cd FastHepSim/libraries/
+./install.sh
+</code>
+This installs "FastHepSim" which includes Delphes, ProMC and hs-tools to work with HepSim. Then setup the environment
+<code bash>
+cd .. # go to the root directory
+source setup.sh
+</code>
+Next, go to the analysis example:
+<code bash>
+cd analysis
+make
+</code>
+This compiles the analysis program (analysis.cc) that fills jetPT and muonPT histograms.
+Now we need to bring  data from [[http://atlaswww.hep.anl.gov/hepsim/| HepSim]] and put them somewhere. For this example,
+we will copy data to the "data" directory:
+<code bash>
+hs-get http://mc.hep.anl.gov/asc/hepsim/events/pp/100tev/higgs_ttbar_mg5 data 2 3
+</code>
+This copies 3 files in 2 threads and put them to the directory "data". Now we are ready to run over these 3 files:
+<code bash>
+./Make_input data  # creates inputdata.txt
+./analysis delphes_card_FCC_basic_notau.tcl histo.root inputdata.txt
+</code>
+The first command creates a file "inputdata.txt" with input data. Then the program "analysis" reads the configuration file, data and generates "histo.root"
+with output histograms. This example uses "delphes_card_FCC_basic_notau.tcl" Delphes configuration file describing a basic FCC detector geometry.
+Note that we have removed  tau tagging since we run over slimmed events with missing mothers of particles.
+If you want to access other objects (photons, electrons, b-jets),
+use [[https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/Arrays | Delphes definitions of arrays]] inside the source code "analysis.cc".
+You can put external files into the src/ directory where it will be found by Makefile.
+If you still want to look at the event structure in the form of ROOT tree, run the usual Delphes command:
+<code bash>
+../libraries/Delphes/DelphesProMC  delphes_card_FCC_basic_notau.tcl  output.root data/mg5_Httbar_100tev_001.promc
+</code>
+where output.root will contain all reconstructed objects. In this case, add "TreeWriter" after "ScalarHT".
+If the input file contains complete (non-slimmed) record, one can add "tau" reconstruction ("TauTagging" line).
+Try also more sophisticated detector-geometry cards:
+  * examples/delphes_card_Snowmass_NoPileUp.tcl - similar to Snowmass 2013. It has CA (fat) jets and B-tagging
+  * examples/delphes_card_ATLASLIKE.tcl         - similar to ATLAS detector (comes with Delphes)
+Note that "TreeWriter" module should be enabled when creating ROOT files, and disabled when using analysis mode.
+====== A note for ANL cluster  ======
+For ANL cluster, you do not need to install Delphes. Simply run the reconstruction as:
+<code bash>
+source /share/sl6/set_asc.sh
+$DELPHES/DelphesProMC delphes_card_FCC_notau.tcl mg5_ttbar_100tev_001.root mg5_ttbar_100tev_001.promc
+</code>
+The cards are located in $DELPHES/examples.
+If you want to run over multiple ProMC files without manual download, use this command:
+<code bash>
+java -cp hepsim.jar hepsim.Exec DelphesProMC delphes.tcl output.root [URL] [Nfiles]
+</code>
+where [URL] is HepSim location of files and  [Nfiles] is the number of files for processing.
+The output ROOT will be located inside the "hepsim_output" directory.
+Here is a small example:
+<code bash>
+java -cp hepsim.jar hepsim.Exec DelphesProMC delphes.tcl output.root  http://mc.hep.anl.gov/asc/hepsim/events/pp/100tev/higgs_ttbar_mg5 5
+</code>
+which processes 5 files from [[http://atlaswww.hep.anl.gov/hepsim/info.php?item=2|Higgs to TTbar sample]].
+Skip "5" at the end to process all files.
+====== Record slimming ======
+Particle records from the generators based on  LO/NLO+parton showers calculations
+(PYTHIA, HERWIG, MADGRAPH) are often "slimmed" to reduce file sizes. In the case when
+records are slimmed, the following algorithm is used:
+<code python>
+(status=1 && pT>0.3 GeV ) or   # keep final states with pT>0.3 GeV
+(PID=5 || PID=6)  or           # keep b or top quark
+(PID>22 && PID<38)  or         # keep exotics and Higgs
+(PID>10 && PID<17)  or         # keep all leptons and neutrinos
+</code>
+where PID is absolute value of particle codes. Leptons ane neutrinos are also affected by the slimming pT cut.
+Note: for 100 TeV collisions, the pT cut is increased from 0.3 to 0.4 GeV.
+For NLO calculations with a few partons + PDF weights, the complete event records are stored.
+In the case when the slimming is applied, file sizes are reduced by x2 -  x3. In some situation, slimming
+can affect detector simulation. For example, you should turn of tau reconstruction in Delphes when slimming is used.

ATLAS Support Center

User Tools

Site Tools

Differences

Page Tools