MadGraph5_aMC@NLO

How to generate .root file in MG5

Asked by Saumyen Kundu

Hi,

How can I generate .root files in MG5 (version = 2.6.3.2)? I installed ExRootAnalysis. But I don't understand what does it do. I'm still getting only .lhe output.
Though I got a warning while installing ExRootAnalysis as in below:

-----------------------------------
>> Compiling src/ExRootXDRReader.cc
src/ExRootXDRReader.cc: In member function ‘void ExRootXDRReader::ReadRaw(void*, int)’:
src/ExRootXDRReader.cc:64:10: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
     fread(value, 1, size + rndup, fFile);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
------------------------------------

Is his the reason I'm not getting .root output or it's something else? Or, ExRootAnalysis doesn't generate .root output at all?
It will be very grateful if it's solved.

Regards,

Saumyen

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Saumyen Kundu
Solved:
Last query:
Last reply:
Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

In order to have MG5 to call ExRootAnalysis, you have to set analysis = ExRootAnalysis at the first question asked.
Did you do that?

Otherwise, is ExRootAnalysis compiled correctly (without a crash?) For more information about such warning, you will need to contact ExRootAnalysis author actually, I can not help on that.

Cheers,

Olivier

Revision history for this message
Saumyen Kundu (saumyen.k) said : 		#2

Hi Olivier,

Yeah, I had set analysis=ExRootAnalysis. But I was thinking MG5 will generate a .root file automatically alongwith the .lhe file. But later I could generate the .root file with the command "./ExRootLHEFConverter file.lhe file.root".

And to say about the compilation, only the 'ExRootXDRReader' had some problem as I quoted the warning message earlier. Does that pose any problem anywhere?

I have another question regarding this just to know. What actually happens when we call ExRootAnalysis in MG5. I mean if we convert a .lhe file which was generated with analysis=OFF, what will happen?

Thanking you for your time and valued inputs,

Saumyen

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

This warning sounds quite safe to ignore but I'm not a C++ expert.

>I have another question regarding this just to know. What actually happens when we call ExRootAnalysis in MG5. I mean if we convert a .lhe file which was generated with analysis=OFF, what will happen?

In principle, we simply just run ./ExRootLHEFConverter file.lhe file.root

I will check if I can reproduce your issue on some of my (virtual) machine and fix it if I reproduce it.

Thanks,

Olivier

Revision history for this message
Saumyen Kundu (saumyen.k) said : 		#4

Hi

Thank you Olivier for the inputs, thank you so much.

Saumyen