dynamic.doc

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`Dynamic' Analysis Mode

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The C code in dynamic.C and the script run_dynamic constitute a typical set of files for running in 'dynamic' mode. The script run_dynamic shows the full compilation+link sequence required to build the executable.

The advantages of the "dynamic" mode are:

• The code is compiled, so execution is fast.

• Since the libraries are requested at run time, the executable is rather small (< 100 kbytes in the example). This is ideal if you do not want to fill up your disk space with unnecessary stuff.

• The default ROOT versions are distributed only with "shared" libraries, this is the natural way of using ROOT.

There are also some disadvantages:

• To run tests on small files and many times, an interpreted mode, like CINT or Python are more convenient.

• Since the executable is dynamic, you can not run it on another Linux machine, unless you are sure that the required run-time libraries exist (test if there are missing libraries with: "ldd dynamic.exe") and that they are compatible (this can be an issue with different ROOT versions: the best way to test it is by just running it). This can also be particularly a problem if you are going to submit your analysis to a batch queue.

Some AMS specific issues follow:

• We can add several Root files with the AMSChain::Add("file") method. The AMSChain class inherits all the methods of the TChain class, but simplifies the life by hiding some AMS internal operations. Example:
  AMSChain* ams = new AMSChain;
  ams->Add("../files/test.root");
  ams->Add("rfio:my_castor_file.root");
  
  

• The analysis is performed on AMSEventR objects:
  
  "AMSEventR* pev = ams.GetEvent()"
  
  
  "AMSEventR* pev = ams.GetEvent(entry_number)"
  
  
  "AMSEventR* pev = ams.GetEvent(run_number, event_number)"
  
  If you prefer not to do pointer coding like "pev->whatever", you can add:
  "AMSEventR &ev = *pev;"
  
  and use "ev.whatever" from that point on.

• In order to access in a simple way all relevant pieces of information many useful definitions, via pointers and vectors, are implemented. For example, the number of hits in ECAL is given by::
  
  cout << "#Ehits: " << ev.nEcalHit() << endl;
  
  or, alternatively:
  cout << "#Ehits: " << pev->nEcalHit() << endl;
  
  The "i" Hit in ECAL belongs to the class EcalHitR, and it may be accessed either as:
  
  EcalHitR hit = ev.EcalHit(i);
  
  or via the pointers:
  
  EcalHitR* phit = pev->pEcalHit(i);
  
  A reference to the ith element is obtained as:
  EcalHitR* phit = &ev.EcalHit(i);
  
  The full list of AMS classes and attributes can be found HERE . For instance, in EcalHitR the first member is "Status", which can be accessed either as:
  
  int stat = ev.EcalHit(i).Status;
  
  
  or:
  int stat = pev->pEcalHit(i)->Status;
  
  
  

#!/bin/sh

file="dynamic.C"
exe="dynamic.exe"

system=`uname`

# Use all libs
#all_libs=1
# Use just libAMSRoot
unset all_libs

AMSLIBS="../lib/libAMSRoot.so"
if [ "$system" = "Darwin" ]; then
      AMSLIBCMD="-dylib_file /lib/libAMSRoot.so:$PWD/../lib/libAMSRoot.so $PWD/../lib/libAMSRoot.so"
      ROOTLIBS="`${ROOTSYS}/bin/root-config --glibs` -lASImage -lMinuit"
      EXTRALIBS="-ldl"
      CXXOPTS="-Wno-deprecated -bind_at_load"
else
      AMSLIBCMD="-Xlinker -R../lib -L../lib -lAMSRoot"
      ROOTLIBS="-Xlinker -R${ROOTSYS}/lib `${ROOTSYS}/bin/root-config --glibs` -lASImage -lMinuit"
      EXTRALIBS="-ldl -lcrypt"
      CXXOPTS="-Wno-deprecated"
fi

machine=`uname -m`
if [ "$machine" = "x86_64" ]; then
      CXXOPTS="${CXXOPTS} -fPIC -m32"
fi


AMSINCS="-I../lib/AMSRoot"
if [ -n "$all_libs" ]; then
  old_dir=${PWD}
  cd ../lib
  for dir in `ls -d */` ; do
      dir=${dir/\//}
      if [ "${dir}" != "CVS" -a "${dir}" != "AMSRoot" ]; then
            AMSINCS="${AMSINCS} -I../lib/${dir}"
            AMSLIBS="${AMSLIBS} ../lib/lib${dir}.so"
            AMSLIBCMD="${AMSLIBCMD} -l${dir}"
      fi      
  done
  cd ${old_dir}
fi

if [ "$system" != "Darwin" ]; then
 if [ "`/usr/bin/gcc -dumpversion`" == "2.96" ]; then
  if [ -e "/usr/local/gcc-alt-3.2.3" ]; then
      export PATH=/usr/local/gcc-alt-3.2.3/bin:$PATH
      export LD_LIBRARY_PATH=/usr/local/gcc-alt-3.2.3/lib:$LD_LIBRARY_PATH
  fi
 fi
fi

ROOTINCDIR=`${ROOTSYS}/bin/root-config --incdir`

INCS="${AMSINCS} -I${ROOTINCDIR}"

RH9add=""
if [ -e "/usr/lib/ctype.o" ]; then
 RH9add="-Wl,/usr/lib/ctype.o"
fi

echo -e "\n>>> Recreating libraries if necessary"
old_dir=$PWD
cd ../lib/ >/dev/null
make shared
if [ -n "$all_libs" ]; then
      make utils_shared
fi
cd $old_dir

echo -e "\n>>> COMPILING and LINKING: ${file}"
make -f - -s <<!
SHELL=/bin/sh

${exe}: ${file} ${AMSLIBS}
        g++ ${CXXOPTS} ${INCS} -o ${exe} ${file} ${AMSLIBCMD} ${ROOTLIBS} ${EXTRALIBS} ${RH9add}
!

echo -e "\n>>> EXECUTING: ${exe}"
if [ "$system" = "Darwin" ]; then
      export DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:../lib
fi
${exe}

#include <root.h>
#include "TRint.h"
#include "TFile.h"
#include "TH1F.h"
int main(){

      // Do not use this when linking with static libraries
      TRint* app = new TRint("AMS Root Application", 0, 0);

      AMSChain* ams = new AMSChain;
      ams->Add("../files/test.root");
      //ams->Add("http://pcamsf0.cern.ch/f2dah1/MC/AMS02/2004A/protons/el.pl1.10200/738197524.0000001.root");
      //ams->Add("rfio:/castor/cern.ch/ams/MC/AMS02/2004A/protons/el.pl1.10200/738197524.0000001.root");

      TFile* hfile = new TFile ("amstest.root", "RECREATE"); 

      AMSEventList* list = new AMSEventList;

      TH1F* hrig = new TH1F ("hrig", "Momentum (GeV)", 50, -10., 10.);
      
      AMSEventR* pev = NULL;
      while (pev=ams->GetEvent()) {
            for (int i=0; i<pev->nParticle(); i++) {
                  ParticleR* part = pev->pParticle(i);
                  hrig->Fill(part->Momentum);
                  if (pev->nVertex()>0) {
                          list->Add(pev); // Add to list of selected events
                          pev->Fill(); // write it into output ROOT file
                  }
            }
      }

      hrig->Draw();
      hfile->Write();
      list->Write("select.list");

      printf("We have processed %d events\n", (int)ams->GetEntries());
      printf("Histograms saved in '%s'\n", hfile->GetName());

      // Do not use this when linking with static libraries
      app->Run();
}

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