Changes between Initial Version and Version 1 of OutDated/FAQ

Timestamp:

Jul 1, 2011, 10:24:57 AM (13 years ago)

Author:

cp3-support

Comment:

--

OutDated/FAQ

@@ +1 @@
+=Frequently Asked Questions=
+
+==Miscellaneous==
+
+(Q) How can I use the mother/daughter particles in the GEN branch?
+
+(A) Here is a sample code
+
+This code prints the kinematics of each central tau in the event, as well as the list of all its daughter particles.
+
+{{{
+ {
+ 
+   TIter itGen((TCollection*)GEN);
+   TRootGenParticle *part;
+
+   // creates the array of particles
+   TSimpleArray array;
+   itGen.Reset();
+   while( (part = (TRootGenParticle*) itGen.Next()) )
+     {
+       array.Add(part);
+     }
+
+   itGen.Reset();
+   while((part = (TRootGenParticle*) itGen.Next()))
+     {
+        // for tau leptons which are inside tracker:
+        if(abs(part->PID)==15 && 
+           fabs(part->Eta)<2.5 )
+          {
+             Int_t Qfille  = part->D1; // index of first daughter
+             Int_t Qfille2 = part->D2; // index of second daughter
+
+             // if the index of first daughter is valid:
+             if(Qfille < array.GetEntries() && 
+                Qfille > 0)
+               {
+                 // prints the list of daughter particles coming from this tau lepton
+                 cout << "it is a tau lepton(" << part->PID << ") with these daughters : ";
+                 for(int i=Qfille; i<=Qfille2; i++)  // beware! it is less-or-equal !
+                   {
+                     cout << array[i]->PID << ", ";
+                   }
+
+                 // prints the kinematics of the tau-lepton
+                 cout << "\t eta= " << part->Eta 
+                      << ", phi= "  << part->Phi 
+                      << ", E= "    << part->E 
+                      << " pt= "    << part->PT 
+                      << endl;
+                }
+          }
+      }
+}}}   
+         
+To try this sample code, one can copy-and-paste it in line 160 of the file Examples/src/Analysis_Ex.cc
+(Q) How can I delete information from a root file ?
+
+(A) Here is a sample code for deleting the GEN tree
+
+If you want to drop some information from the root files in order to make them lighter, here is the receipe
+It is quite easy. First open your root file in write mode, then delete the object, save the file and then close the file.
+
+{{{
+root [5]
+TFile * myfile = new TFile("test.root","UPDATE");
+.ls
+myfile->Delete("GEN;1");
+.ls
+myfile->Save();
+myfile->Close();
+// opens the file in write-mode
+// shows its contents
+// deletes tree from memory
+// deleted tree has disappeared
+// writes changes on disk
+// closes the file
+}}}
+
+(Q) "Undefined symbol" error at run time
+
+(A) Some library specific to your ROOT installation should be added
+
+On non-default installations of ROOT, such errors could happen. In particular if the _hepevt_ symbol is not defined, this reflects the use of libEGPythia6 in your ROOT installation. For instance (as an illustration, this error occured on a Mac OS X)
+{{{
+        me@mylaptop:~$ ./Delphes 
+        dyld: Symbol not found: _hepevt_
+        Referenced from: /usr/local/root/lib/libEG.dylib
+        Expected in: dynamic lookup
+}}}
+In order to solve this problem, just link the corresponding library (in this particular case, libEGPythia6 contains the definition of the _hepevt_ symbol) in the compilation command of Delphes. For this, edit the genMakefile.tcl file by adding -lEGPythia6 at the end of the LIBS line (it should be the line number 221):
+{{{
+        LIBS = $(ROOTLIBS) -lEG $(SYSLIBS) -lEGPythia6
+}}}
+Then, you should clean and recompile Delphes, and it will run smoothly:
+{{{
+        me@mylaptop:~$ make clean
+        me@mylaptop:~$ make
+        me@mylaptop:~$ ./Delphes
+}}}
+In addition, in order to find in which library a given variable is defined, it is worth knowing the command nm which lists the symbols defined in a library. For instance,
+{{{
+        me@mylaptop:~$ nm -a libEGPythia6.so | grep _hepevt_
+        003a8a70 S _hepevt_
+        me@mylaptop:~$ nm -a libEG.so | grep _hepevt_
+                 U _hepevt_ 
+}}}
+
+Here the symbol _hepevt_ is defined in libEGPythia6 (as mentioned by the S character) but not in libEG.so (as meant by the U character). For more information, refer to the manpage of nm. 
+
+(Q) I have got a strange distribution for the Phi of the jets
+
+(A) The default binning from ROOT used for plotting is not adequate
+
+When the bin size is not correct when displaying a variable, it might be that you obtain distributions with periodic pikes, like here. In particular, for the azimuthal angle Phi, you might pay attention to have, say, 5-degree wide bins:
+{{{
+        root[0] TH1F * phi = new TH1F("phi","",80,-200,200);
+        root[1] Analysis->Draw("(Jet.Phi)/acos(-1)*180. >> phi",
+                                    "Jet.Eta<1.5 && Jet.Eta>-1.5");
+        root[2] phi->GetXaxis()->SetTitle("Jet.Phi [degree]");
+}}}
+This gives a plot with the expected distribution like here or here. 
+
+Delphes options:Convertors_Only LHCO_Only Trigger_Only
+
+(Q) Delphes complains that data/DataCardDet.dat is not found.
+
+(A) The default datacard names have been changed.
+
+In recent versions of the code (>1.4beta), the default names have been changed to DetectorCard.dat. Similarly, trigger cards are now called TriggerCard.dat 
+
+(Q) May I run the convertor stage independently before running Delphes?
+
+(A) Yes, you can convert your generator-level input files
+
+Just by running the 'Convertors_Only' executable:
+{{{
+        me@mylaptop:~$ ./Convertors_Only
+        Usage: ./Convertors_Only input_file output_file
+        input_list - list of files in Ntpl, StdHep of LHEF format,
+        output_file - output file.
+        me@mylaptop:~$ ./Convertors_Only TEST.list converted.root
+}}}
+
+(Q-options2) Can I easily convert my ROOT output to LHCO?
+
+I did not create a LHCO output file when I ran Delphes (FLAG_lhco=0). Can I do this on my ROOT output file?
+(A) The LHCO output file can be easily created out-of your Delphes ROOT output file.
+
+Just by running the 'LHCO_Only' executable:
+{{{
+        me@mylaptop:~$ ./LHCO_Only
+        Usage: ./LHCO_Only input_file [runlog_file]
+        input_file - file in Delphes root format,
+        [runlog_file] - the corresponding log file (optional)
+        me@mylaptop:~$ ./LHCO_Only test.root
+}}}
+
+(Q-options1) Can I easily reprocess the trigger stage?
+
+I did not run the triggers when I ran Delphes (FLAG_trigger=0). Can I reprocess this on my output file?
+(A) There is no problem to re-run the trigger on a Delphes output-file.
+
+Just run the 'Trigger_Only' executable:
+{{{
+        me@mylaptop:~$ ./Trigger_Only
+        Usage: ./Trigger_Only input_file output_file [detector_card] [trigger_card]
+        input_file - file in Delphe root format,
+        trigger_card - Datacard containing the trigger algorithms (optional)
+        me@mylaptop:~$ ./Trigger_Only test_without_trigger.root test_with_trigger.root \ 
+                        data/mydetector.dat data/mytrigger.dat
+}}}
+
+== FROG related questions ==
+
+(Q-frog5) I do not remember how to run FROG
+
+(A) Just run the "frog" executable in Utilities/FROG
+{{{
+        me@mylaptop:~$ cd Utilities/FROG
+        me@mylaptop:~$ ./frog
+}}}
+
+(Q-frog4) frog executable is not found!
+{{{
+        me@mylaptop:~$ ./Utilities/FROG/frog
+        ./Utilities/FROG/frog: No such file or directory
+}}}
+(A) you should have compiled FROG first.
+{{{
+        me@mylaptop:~$ cd Utilities/FROG
+        me@mylaptop:~$ make
+}}}
+
+(Q-frog3) How should I know which external libraries I need for FROG ?
+
+(A) Please refer to this page on the FROG website
+
+Look at the Getting started page. You will need OpenGL, GLUT, X11-devel, Curl. 
+For instance, here are the packages you could use in some Linux installation: 
+OpenGL: 
+{{{
+    xorg-x11-Mesa-libGL-6.8.2-1.EL.33.0.2 
+    xorg-x11-Mesa-libGLU-6.8.2-1.EL.33.0.2 
+}}}
+GLUT: 
+{{{
+    freeglut-2.2.0-14 
+    freeglut-devel-2.2.0-14 
+}}}
+X11-devel: 
+{{{
+    xorg-x11-devel-6.8.2-1.EL.33.0.2 
+}}}
+CURL:
+{{{ 
+    libcurl
+}}}
+For instance, to install these on Fedora 12: try
+{{{
+sudo yum install mesa-libGL mesa-libGL-devel mesa-libGLU freeglut freeglut-devel libX11-devel libcurl
+}}}
+
+(Q-frog2) FROG complains that libcurl is missing. What should I do?
+
+(A) First, make sure the libcurl library is installed on your computer.
+
+locate it on your computer
+{{{
+        me@mylaptop:~$ locate libcurl.so
+        /usr/lib/libcurl.so
+}}}
+
+if the library is not present, take it from the internet (http://curl.haxx.se/) or via installers like "apt-get" (ubuntu systems) or "yum" (fedora systems) 
+if the libcurl.so is not found, juste make a symbolic link in Utilities/FROG/Lib:
+{{{
+        me@mylaptop:~$ cd Utilities/FROG/Lib
+        me@mylaptop:~$ ln -s /usr/lib/libcurl.so
+        me@mylaptop:~$ ls -l libcurl.so
+        lrwxrwxrwx  1 me me 21 Jan  7 15:19 libcurl.so -> /usr/lib/libcurl.so.4.0.1
+}}}
+now it should work properly
+
+For instance, to install these on Fedora 12: try
+sudo yum install libcurl
+
+(Q-frog1) (fixed) there are many lines printed at the end of the run of Delphes. Is it an error?
+{{{
+55555 D0
+ - 20000 D0
+ -  - 3000 (detId=900000000 Name=Delphes)
+ -  -  - 3000 (detId=910000000 Name=Tracker)
+ -  -  -  - 41040 (detId=9100010)
+ -  -  -  - 41040 (detId=9100020)
+ -  -  -  - 41040 (detId=9100030)
+ -  -  -  - 41040 (detId=9100040)
+...
+}}}
+(A) no, this is normal
+
+This is just the output of FROG, showing that everything is ok. You should find your *vis and *geom files when it has ended. This output is not visible anymore, since Delphes-1.3beta 
+
+Mac OS-X
+
+(Q-mac 2) Delphes is not compiling properly on Mac OS-X
+
+(A) One modification is required in the Makefile
+
+--- NOT needed anymore for Delphes V > 1.7 --- 
+In Delphes' genMakefile.tcl, you should add "-Dmacos " in the CXXFLAGS definition (line 219): 
+{{{
+CXXFLAGS += $(ROOTCFLAGS) -Dmacos -DDROP_CGAL -I. -Iinterface ...
+}}}
+Check also that for your ROOT installation you have defined the following environment variables: ROOTSYS, PATH, LD_LIBRARY_PATH and DYLD_LIBRARY_PATH (see below).
+
+
+(Q-mac 1) FROG is not compiling properly on Mac OS-X
+
+(A) One modification is required in FROG's Makefile
+
+Open Utilities/FROG/Makefile. There, you should link the libcurl library in the compilation line of libfrog: 
+{{{
+Utilities/FROG/Makefile:
+libfrog.dylib : $(OBJS)
+        $(CXX) ... $(ARCHDEPENDENT) -lcurl -lX11 -lz -lpng -o $(LIBDIR)/$@
+}}}
+Do not forget to recompile FROG from its directory (Utilities/FROG)
+{{{
+        me@mylaptop:~$ cd Utilities/FROG
+        me@mylaptop:~$ make
+}}}
+
+== ROOT basics ==
+
+(Q-root 1) I am not familiar with ROOT, how can I start?
+
+(A) Refer to our online manual
+
+You will find basic commands here. 
+
+(Q-root 2) ROOT does not seem to work properly, or Delphes complains about ROOT
+
+(A) It could be that the required environment variables are not declared
+
+ROOT will properly work only if environment variables such as ROOTSYS are properly defined. To check this, try the following command:
+   echo $ROOTSYS
+This should output the path to your ROOT installation folder (e.g. /usr/bin/root5.18). You must check and define all the following environment variables: ROOTSYS, LD_LIBRARY_PATH and PATH. In addition, for MacOSX, one must have DYLD_LIBRARY_PATH. 
+Following ROOT website, here are the correct ways to define these variables. You must know which kind of shell you are running in your terminal (the command echo $SHELL will give you the answer to this question).
+if you are running a shell from the "sh family" (e.g. a bash shell):
+{{{
+export PATH=$ROOTSYS/bin:$PATH
+export LD_LIBRARY_PATH=$ROOTSYS/lib:$LD_LIBRARY_PATH
+}}}
+In addition, for MacOS X only:
+{{{
+export DYLD_LIBRARY_PATH=$ROOTSYS/lib:$DYLD_LIBRARY_PATH
+}}}
+
+if your shell is from the "csh family":
+{{{
+setenv PATH ${ROOTSYS}/bin:${PATH}
+setenv LD_LIBRARY_PATH ${ROOTSYS}/lib:${LD_LIBRARY_PATH}
+rehash
+In addition, for MacOS X only:
+setenv DYLD_LIBRARY_PATH ${ROOTSYS}/lib:${DYLD_LIBRARY_PATH}
+}}}